Commit Graph

15515 Commits

Author SHA1 Message Date
Linus Torvalds 4d02da974e Networking fixes for 5.10-rc5, including fixes from the WiFi (mac80211),
can and bpf (including the strncpy_from_user fix).
 
 Current release - regressions:
 
  - mac80211: fix memory leak of filtered powersave frames
 
  - mac80211: free sta in sta_info_insert_finish() on errors to avoid
              sleeping in atomic context
 
  - netlabel: fix an uninitialized variable warning added in -rc4
 
 Previous release - regressions:
 
  - vsock: forward all packets to the host when no H2G is registered,
            un-breaking AWS Nitro Enclaves
 
  - net: Exempt multicast addresses from five-second neighbor lifetime
         requirement, decreasing the chances neighbor tables fill up
 
  - net/tls: fix corrupted data in recvmsg
 
  - qed: fix ILT configuration of SRC block
 
  - can: m_can: process interrupt only when not runtime suspended
 
 Previous release - always broken:
 
  - page_frag: Recover from memory pressure by not recycling pages
               allocating from the reserves
 
  - strncpy_from_user: Mask out bytes after NUL terminator
 
  - ip_tunnels: Set tunnel option flag only when tunnel metadata is
                present, always setting it confuses Open vSwitch
 
  - bpf, sockmap:
    - Fix partial copy_page_to_iter so progress can still be made
    - Fix socket memory accounting and obeying SO_RCVBUF
 
  - net: Have netpoll bring-up DSA management interface
 
  - net: bridge: add missing counters to ndo_get_stats64 callback
 
  - tcp: brr: only postpone PROBE_RTT if RTT is < current min_rtt
 
  - enetc: Workaround MDIO register access HW bug
 
  - net/ncsi: move netlink family registration to a subsystem init,
              instead of tying it to driver probe
 
  - net: ftgmac100: unregister NC-SI when removing driver to avoid crash
 
  - lan743x: prevent interrupt storm on open
 
  - lan743x: fix freeing skbs in the wrong context
 
  - net/mlx5e: Fix socket refcount leak on kTLS RX resync
 
  - net: dsa: mv88e6xxx: Avoid VLAN database corruption on 6097
 
  - fix 21 unset return codes and other mistakes on error paths,
    mostly detected by the Hulk Robot
 
 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-5.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from Jakub Kicinski:
 "Networking fixes for 5.10-rc5, including fixes from the WiFi
  (mac80211), can and bpf (including the strncpy_from_user fix).

  Current release - regressions:

   - mac80211: fix memory leak of filtered powersave frames

   - mac80211: free sta in sta_info_insert_finish() on errors to avoid
     sleeping in atomic context

   - netlabel: fix an uninitialized variable warning added in -rc4

  Previous release - regressions:

   - vsock: forward all packets to the host when no H2G is registered,
     un-breaking AWS Nitro Enclaves

   - net: Exempt multicast addresses from five-second neighbor lifetime
     requirement, decreasing the chances neighbor tables fill up

   - net/tls: fix corrupted data in recvmsg

   - qed: fix ILT configuration of SRC block

   - can: m_can: process interrupt only when not runtime suspended

  Previous release - always broken:

   - page_frag: Recover from memory pressure by not recycling pages
     allocating from the reserves

   - strncpy_from_user: Mask out bytes after NUL terminator

   - ip_tunnels: Set tunnel option flag only when tunnel metadata is
     present, always setting it confuses Open vSwitch

   - bpf, sockmap:
      - Fix partial copy_page_to_iter so progress can still be made
      - Fix socket memory accounting and obeying SO_RCVBUF

   - net: Have netpoll bring-up DSA management interface

   - net: bridge: add missing counters to ndo_get_stats64 callback

   - tcp: brr: only postpone PROBE_RTT if RTT is < current min_rtt

   - enetc: Workaround MDIO register access HW bug

   - net/ncsi: move netlink family registration to a subsystem init,
     instead of tying it to driver probe

   - net: ftgmac100: unregister NC-SI when removing driver to avoid
     crash

   - lan743x:
      - prevent interrupt storm on open
      - fix freeing skbs in the wrong context

   - net/mlx5e: Fix socket refcount leak on kTLS RX resync

   - net: dsa: mv88e6xxx: Avoid VLAN database corruption on 6097

   - fix 21 unset return codes and other mistakes on error paths, mostly
     detected by the Hulk Robot"

* tag 'net-5.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (115 commits)
  fail_function: Remove a redundant mutex unlock
  selftest/bpf: Test bpf_probe_read_user_str() strips trailing bytes after NUL
  lib/strncpy_from_user.c: Mask out bytes after NUL terminator.
  net/smc: fix direct access to ib_gid_addr->ndev in smc_ib_determine_gid()
  net/smc: fix matching of existing link groups
  ipv6: Remove dependency of ipv6_frag_thdr_truncated on ipv6 module
  libbpf: Fix VERSIONED_SYM_COUNT number parsing
  net/mlx4_core: Fix init_hca fields offset
  atm: nicstar: Unmap DMA on send error
  page_frag: Recover from memory pressure
  net: dsa: mv88e6xxx: Wait for EEPROM done after HW reset
  mlxsw: core: Use variable timeout for EMAD retries
  mlxsw: Fix firmware flashing
  net: Have netpoll bring-up DSA management interface
  atl1e: fix error return code in atl1e_probe()
  atl1c: fix error return code in atl1c_probe()
  ah6: fix error return code in ah6_input()
  net: usb: qmi_wwan: Set DTR quirk for MR400
  can: m_can: process interrupt only when not runtime suspended
  can: flexcan: flexcan_chip_start(): fix erroneous flexcan_transceiver_enable() during bus-off recovery
  ...
2020-11-19 13:33:16 -08:00
Dongli Zhang d8c19014bb page_frag: Recover from memory pressure
The ethernet driver may allocate skb (and skb->data) via napi_alloc_skb().
This ends up to page_frag_alloc() to allocate skb->data from
page_frag_cache->va.

During the memory pressure, page_frag_cache->va may be allocated as
pfmemalloc page. As a result, the skb->pfmemalloc is always true as
skb->data is from page_frag_cache->va. The skb will be dropped if the
sock (receiver) does not have SOCK_MEMALLOC. This is expected behaviour
under memory pressure.

However, once kernel is not under memory pressure any longer (suppose large
amount of memory pages are just reclaimed), the page_frag_alloc() may still
re-use the prior pfmemalloc page_frag_cache->va to allocate skb->data. As a
result, the skb->pfmemalloc is always true unless page_frag_cache->va is
re-allocated, even if the kernel is not under memory pressure any longer.

Here is how kernel runs into issue.

1. The kernel is under memory pressure and allocation of
PAGE_FRAG_CACHE_MAX_ORDER in __page_frag_cache_refill() will fail. Instead,
the pfmemalloc page is allocated for page_frag_cache->va.

2: All skb->data from page_frag_cache->va (pfmemalloc) will have
skb->pfmemalloc=true. The skb will always be dropped by sock without
SOCK_MEMALLOC. This is an expected behaviour.

3. Suppose a large amount of pages are reclaimed and kernel is not under
memory pressure any longer. We expect skb->pfmemalloc drop will not happen.

4. Unfortunately, page_frag_alloc() does not proactively re-allocate
page_frag_alloc->va and will always re-use the prior pfmemalloc page. The
skb->pfmemalloc is always true even kernel is not under memory pressure any
longer.

Fix this by freeing and re-allocating the page instead of recycling it.

References: https://lore.kernel.org/lkml/20201103193239.1807-1-dongli.zhang@oracle.com/
References: https://lore.kernel.org/linux-mm/20201105042140.5253-1-willy@infradead.org/
Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Cc: Bert Barbe <bert.barbe@oracle.com>
Cc: Rama Nichanamatlu <rama.nichanamatlu@oracle.com>
Cc: Venkat Venkatsubra <venkat.x.venkatsubra@oracle.com>
Cc: Manjunath Patil <manjunath.b.patil@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
Cc: SRINIVAS <srinivas.eeda@oracle.com>
Fixes: 79930f5892 ("net: do not deplete pfmemalloc reserve")
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20201115201029.11903-1-dongli.zhang@oracle.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-11-18 15:21:56 -08:00
Linus Torvalds a50cf15906 Merge branch 'for-5.10-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu
Pull percpu fix and cleanup from Dennis Zhou:
 "A fix for a Wshadow warning in the asm-generic percpu macros came in
  and then I tacked on the removal of flexible array initializers in the
  percpu allocator"

* 'for-5.10-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu:
  percpu: convert flexible array initializers to use struct_size()
  asm-generic: percpu: avoid Wshadow warning
2020-11-15 08:57:19 -08:00
Mike Kravetz 336bf30eb7 hugetlbfs: fix anon huge page migration race
Qian Cai reported the following BUG in [1]

  LTP: starting move_pages12
  BUG: unable to handle page fault for address: ffffffffffffffe0
  ...
  RIP: 0010:anon_vma_interval_tree_iter_first+0xa2/0x170 avc_start_pgoff at mm/interval_tree.c:63
  Call Trace:
    rmap_walk_anon+0x141/0xa30 rmap_walk_anon at mm/rmap.c:1864
    try_to_unmap+0x209/0x2d0 try_to_unmap at mm/rmap.c:1763
    migrate_pages+0x1005/0x1fb0
    move_pages_and_store_status.isra.47+0xd7/0x1a0
    __x64_sys_move_pages+0xa5c/0x1100
    do_syscall_64+0x5f/0x310
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

Hugh Dickins diagnosed this as a migration bug caused by code introduced
to use i_mmap_rwsem for pmd sharing synchronization.  Specifically, the
routine unmap_and_move_huge_page() is always passing the TTU_RMAP_LOCKED
flag to try_to_unmap() while holding i_mmap_rwsem.  This is wrong for
anon pages as the anon_vma_lock should be held in this case.  Further
analysis suggested that i_mmap_rwsem was not required to he held at all
when calling try_to_unmap for anon pages as an anon page could never be
part of a shared pmd mapping.

Discussion also revealed that the hack in hugetlb_page_mapping_lock_write
to drop page lock and acquire i_mmap_rwsem is wrong.  There is no way to
keep mapping valid while dropping page lock.

This patch does the following:

 - Do not take i_mmap_rwsem and set TTU_RMAP_LOCKED for anon pages when
   calling try_to_unmap.

 - Remove the hacky code in hugetlb_page_mapping_lock_write. The routine
   will now simply do a 'trylock' while still holding the page lock. If
   the trylock fails, it will return NULL. This could impact the
   callers:

    - migration calling code will receive -EAGAIN and retry up to the
      hard coded limit (10).

    - memory error code will treat the page as BUSY. This will force
      killing (SIGKILL) instead of SIGBUS any mapping tasks.

   Do note that this change in behavior only happens when there is a
   race. None of the standard kernel testing suites actually hit this
   race, but it is possible.

[1] https://lore.kernel.org/lkml/20200708012044.GC992@lca.pw/
[2] https://lore.kernel.org/linux-mm/alpine.LSU.2.11.2010071833100.2214@eggly.anvils/

Fixes: c0d0381ade ("hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization")
Reported-by: Qian Cai <cai@lca.pw>
Suggested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201105195058.78401-1-mike.kravetz@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-14 11:26:04 -08:00
Jason Gunthorpe 96e1fac162 mm/gup: use unpin_user_pages() in __gup_longterm_locked()
When FOLL_PIN is passed to __get_user_pages() the page list must be put
back using unpin_user_pages() otherwise the page pin reference persists
in a corrupted state.

There are two places in the unwind of __gup_longterm_locked() that put
the pages back without checking.  Normally on error this function would
return the partial page list making this the caller's responsibility,
but in these two cases the caller is not allowed to see these pages at
all.

Fixes: 3faa52c03f ("mm/gup: track FOLL_PIN pages")
Reported-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/0-v2-3ae7d9d162e2+2a7-gup_cma_fix_jgg@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-14 11:26:03 -08:00
Laurent Dufour 22e4663e91 mm/slub: fix panic in slab_alloc_node()
While doing memory hot-unplug operation on a PowerPC VM running 1024 CPUs
with 11TB of ram, I hit the following panic:

    BUG: Kernel NULL pointer dereference on read at 0x00000007
    Faulting instruction address: 0xc000000000456048
    Oops: Kernel access of bad area, sig: 11 [#2]
    LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS= 2048 NUMA pSeries
    Modules linked in: rpadlpar_io rpaphp
    CPU: 160 PID: 1 Comm: systemd Tainted: G      D           5.9.0 #1
    NIP:  c000000000456048 LR: c000000000455fd4 CTR: c00000000047b350
    REGS: c00006028d1b77a0 TRAP: 0300   Tainted: G      D            (5.9.0)
    MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 24004228  XER: 00000000
    CFAR: c00000000000f1b0 DAR: 0000000000000007 DSISR: 40000000 IRQMASK: 0
    GPR00: c000000000455fd4 c00006028d1b7a30 c000000001bec800 0000000000000000
    GPR04: 0000000000000dc0 0000000000000000 00000000000374ef c00007c53df99320
    GPR08: 000007c53c980000 0000000000000000 000007c53c980000 0000000000000000
    GPR12: 0000000000004400 c00000001e8e4400 0000000000000000 0000000000000f6a
    GPR16: 0000000000000000 c000000001c25930 c000000001d62528 00000000000000c1
    GPR20: c000000001d62538 c00006be469e9000 0000000fffffffe0 c0000000003c0ff8
    GPR24: 0000000000000018 0000000000000000 0000000000000dc0 0000000000000000
    GPR28: c00007c513755700 c000000001c236a4 c00007bc4001f800 0000000000000001
    NIP [c000000000456048] __kmalloc_node+0x108/0x790
    LR [c000000000455fd4] __kmalloc_node+0x94/0x790
    Call Trace:
      kvmalloc_node+0x58/0x110
      mem_cgroup_css_online+0x10c/0x270
      online_css+0x48/0xd0
      cgroup_apply_control_enable+0x2c4/0x470
      cgroup_mkdir+0x408/0x5f0
      kernfs_iop_mkdir+0x90/0x100
      vfs_mkdir+0x138/0x250
      do_mkdirat+0x154/0x1c0
      system_call_exception+0xf8/0x200
      system_call_common+0xf0/0x27c
    Instruction dump:
    e93e0000 e90d0030 39290008 7cc9402a e94d0030 e93e0000 7ce95214 7f89502a
    2fbc0000 419e0018 41920230 e9270010 <89290007> 7f994800 419e0220 7ee6bb78

This pointing to the following code:

    mm/slub.c:2851
            if (unlikely(!object || !node_match(page, node))) {
    c000000000456038:       00 00 bc 2f     cmpdi   cr7,r28,0
    c00000000045603c:       18 00 9e 41     beq     cr7,c000000000456054 <__kmalloc_node+0x114>
    node_match():
    mm/slub.c:2491
            if (node != NUMA_NO_NODE && page_to_nid(page) != node)
    c000000000456040:       30 02 92 41     beq     cr4,c000000000456270 <__kmalloc_node+0x330>
    page_to_nid():
    include/linux/mm.h:1294
    c000000000456044:       10 00 27 e9     ld      r9,16(r7)
    c000000000456048:       07 00 29 89     lbz     r9,7(r9)	<<<< r9 = NULL
    node_match():
    mm/slub.c:2491
    c00000000045604c:       00 48 99 7f     cmpw    cr7,r25,r9
    c000000000456050:       20 02 9e 41     beq     cr7,c000000000456270 <__kmalloc_node+0x330>

The panic occurred in slab_alloc_node() when checking for the page's node:

	object = c->freelist;
	page = c->page;
	if (unlikely(!object || !node_match(page, node))) {
		object = __slab_alloc(s, gfpflags, node, addr, c);
		stat(s, ALLOC_SLOWPATH);

The issue is that object is not NULL while page is NULL which is odd but
may happen if the cache flush happened after loading object but before
loading page.  Thus checking for the page pointer is required too.

The cache flush is done through an inter processor interrupt when a
piece of memory is off-lined.  That interrupt is triggered when a memory
hot-unplug operation is initiated and offline_pages() is calling the
slub's MEM_GOING_OFFLINE callback slab_mem_going_offline_callback()
which is calling flush_cpu_slab().  If that interrupt is caught between
the reading of c->freelist and the reading of c->page, this could lead
to such a situation.  That situation is expected and the later call to
this_cpu_cmpxchg_double() will detect the change to c->freelist and redo
the whole operation.

In commit 6159d0f5c0 ("mm/slub.c: page is always non-NULL in
node_match()") check on the page pointer has been removed assuming that
page is always valid when it is called.  It happens that this is not
true in that particular case, so check for page before calling
node_match() here.

Fixes: 6159d0f5c0 ("mm/slub.c: page is always non-NULL in node_match()")
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Scott Cheloha <cheloha@linux.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201027190406.33283-1-ldufour@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-14 11:26:03 -08:00
Nicholas Piggin 2da9f6305f mm/vmscan: fix NR_ISOLATED_FILE corruption on 64-bit
Previously the negated unsigned long would be cast back to signed long
which would have the correct negative value.  After commit 730ec8c01a
("mm/vmscan.c: change prototype for shrink_page_list"), the large
unsigned int converts to a large positive signed long.

Symptoms include CMA allocations hanging forever holding the cma_mutex
due to alloc_contig_range->...->isolate_migratepages_block waiting
forever in "while (unlikely(too_many_isolated(pgdat)))".

[akpm@linux-foundation.org: fix -stat.nr_lazyfree_fail as well, per Michal]

Fixes: 730ec8c01a ("mm/vmscan.c: change prototype for shrink_page_list")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vaneet Narang <v.narang@samsung.com>
Cc: Maninder Singh <maninder1.s@samsung.com>
Cc: Amit Sahrawat <a.sahrawat@samsung.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201029032320.1448441-1-npiggin@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-14 11:26:03 -08:00
Zi Yan d20bdd571e mm/compaction: stop isolation if too many pages are isolated and we have pages to migrate
In isolate_migratepages_block, if we have too many isolated pages and
nr_migratepages is not zero, we should try to migrate what we have
without wasting time on isolating.

In theory it's possible that multiple parallel compactions will cause
too_many_isolated() to become true even if each has isolated less than
COMPACT_CLUSTER_MAX, and loop forever in the while loop.  Bailing
immediately prevents that.

[vbabka@suse.cz: changelog addition]

Fixes: 1da2f328fa (“mm,thp,compaction,cma: allow THP migration for CMA allocations”)
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Yang Shi <shy828301@gmail.com>
Link: https://lkml.kernel.org/r/20201030183809.3616803-2-zi.yan@sent.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-14 11:26:03 -08:00
Zi Yan 38935861d8 mm/compaction: count pages and stop correctly during page isolation
In isolate_migratepages_block, when cc->alloc_contig is true, we are
able to isolate compound pages.  But nr_migratepages and nr_isolated did
not count compound pages correctly, causing us to isolate more pages
than we thought.

So count compound pages as the number of base pages they contain.
Otherwise, we might be trapped in too_many_isolated while loop, since
the actual isolated pages can go up to COMPACT_CLUSTER_MAX*512=16384,
where COMPACT_CLUSTER_MAX is 32, since we stop isolation after
cc->nr_migratepages reaches to COMPACT_CLUSTER_MAX.

In addition, after we fix the issue above, cc->nr_migratepages could
never be equal to COMPACT_CLUSTER_MAX if compound pages are isolated,
thus page isolation could not stop as we intended.  Change the isolation
stop condition to '>='.

The issue can be triggered as follows:

In a system with 16GB memory and an 8GB CMA region reserved by
hugetlb_cma, if we first allocate 10GB THPs and mlock them (so some THPs
are allocated in the CMA region and mlocked), reserving 6 1GB hugetlb
pages via /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages will
get stuck (looping in too_many_isolated function) until we kill either
task.  With the patch applied, oom will kill the application with 10GB
THPs and let hugetlb page reservation finish.

[ziy@nvidia.com: v3]

Link: https://lkml.kernel.org/r/20201030183809.3616803-1-zi.yan@sent.com
Fixes: 1da2f328fa ("cmm,thp,compaction,cma: allow THP migration for CMA allocations")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Rik van Riel <riel@surriel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201029200435.3386066-1-zi.yan@sent.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-14 11:26:03 -08:00
Jason Yan a77eedbc87 mm/truncate.c: make __invalidate_mapping_pages() static
Fix the following sparse warning:

  mm/truncate.c:531:15: warning: symbol '__invalidate_mapping_pages' was not declared. Should it be static?

Fixes: eb1d7a65f0 ("mm, fadvise: improve the expensive remote LRU cache draining after FADV_DONTNEED")
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lkml.kernel.org/r/20201015054808.2445904-1-yanaijie@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-02 12:14:19 -08:00
Shijie Luo 3f08842098 mm: mempolicy: fix potential pte_unmap_unlock pte error
When flags in queue_pages_pte_range don't have MPOL_MF_MOVE or
MPOL_MF_MOVE_ALL bits, code breaks and passing origin pte - 1 to
pte_unmap_unlock seems like not a good idea.

queue_pages_pte_range can run in MPOL_MF_MOVE_ALL mode which doesn't
migrate misplaced pages but returns with EIO when encountering such a
page.  Since commit a7f40cfe3b ("mm: mempolicy: make mbind() return
-EIO when MPOL_MF_STRICT is specified") and early break on the first pte
in the range results in pte_unmap_unlock on an underflow pte.  This can
lead to lockups later on when somebody tries to lock the pte resp.
page_table_lock again..

Fixes: a7f40cfe3b ("mm: mempolicy: make mbind() return -EIO when MPOL_MF_STRICT is specified")
Signed-off-by: Shijie Luo <luoshijie1@huawei.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Feilong Lin <linfeilong@huawei.com>
Cc: Shijie Luo <luoshijie1@huawei.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201019074853.50856-1-luoshijie1@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-02 12:14:19 -08:00
Roman Gushchin 8de15e920d mm: memcg: link page counters to root if use_hierarchy is false
Richard reported a warning which can be reproduced by running the LTP
madvise6 test (cgroup v1 in the non-hierarchical mode should be used):

  WARNING: CPU: 0 PID: 12 at mm/page_counter.c:57 page_counter_uncharge (mm/page_counter.c:57 mm/page_counter.c:50 mm/page_counter.c:156)
  Modules linked in:
  CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.9.0-rc7-22-default #77
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-48-gd9c812d-rebuilt.opensuse.org 04/01/2014
  Workqueue: events drain_local_stock
  RIP: 0010:page_counter_uncharge (mm/page_counter.c:57 mm/page_counter.c:50 mm/page_counter.c:156)
  Call Trace:
    __memcg_kmem_uncharge (mm/memcontrol.c:3022)
    drain_obj_stock (./include/linux/rcupdate.h:689 mm/memcontrol.c:3114)
    drain_local_stock (mm/memcontrol.c:2255)
    process_one_work (./arch/x86/include/asm/jump_label.h:25 ./include/linux/jump_label.h:200 ./include/trace/events/workqueue.h:108 kernel/workqueue.c:2274)
    worker_thread (./include/linux/list.h:282 kernel/workqueue.c:2416)
    kthread (kernel/kthread.c:292)
    ret_from_fork (arch/x86/entry/entry_64.S:300)

The problem occurs because in the non-hierarchical mode non-root page
counters are not linked to root page counters, so the charge is not
propagated to the root memory cgroup.

After the removal of the original memory cgroup and reparenting of the
object cgroup, the root cgroup might be uncharged by draining a objcg
stock, for example.  It leads to an eventual underflow of the charge and
triggers a warning.

Fix it by linking all page counters to corresponding root page counters
in the non-hierarchical mode.

Please note, that in the non-hierarchical mode all objcgs are always
reparented to the root memory cgroup, even if the hierarchy has more
than 1 level.  This patch doesn't change it.

The patch also doesn't affect how the hierarchical mode is working,
which is the only sane and truly supported mode now.

Thanks to Richard for reporting, debugging and providing an alternative
version of the fix!

Fixes: bf4f059954 ("mm: memcg/slab: obj_cgroup API")
Reported-by: <ltp@lists.linux.it>
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201026231326.3212225-1-guro@fb.com
Debugged-by: Richard Palethorpe <rpalethorpe@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-02 12:14:18 -08:00
zhongjiang-ali 7de2e9f195 mm: memcontrol: correct the NR_ANON_THPS counter of hierarchical memcg
memcg_page_state will get the specified number in hierarchical memcg, It
should multiply by HPAGE_PMD_NR rather than an page if the item is
NR_ANON_THPS.

[akpm@linux-foundation.org: fix printk warning]
[akpm@linux-foundation.org: use u64 cast, per Michal]

Fixes: 468c398233 ("mm: memcontrol: switch to native NR_ANON_THPS counter")
Signed-off-by: zhongjiang-ali <zhongjiang-ali@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Link: https://lkml.kernel.org/r/1603722395-72443-1-git-send-email-zhongjiang-ali@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-02 12:14:18 -08:00
Mike Kravetz 79aa925bf2 hugetlb_cgroup: fix reservation accounting
Michal Privoznik was using "free page reporting" in QEMU/virtio-balloon
with hugetlbfs and hit the warning below.  QEMU with free page hinting
uses fallocate(FALLOC_FL_PUNCH_HOLE) to discard pages that are reported
as free by a VM.  The reporting granularity is in pageblock granularity.
So when the guest reports 2M chunks, we fallocate(FALLOC_FL_PUNCH_HOLE)
one huge page in QEMU.

  WARNING: CPU: 7 PID: 6636 at mm/page_counter.c:57 page_counter_uncharge+0x4b/0x50
  Modules linked in: ...
  CPU: 7 PID: 6636 Comm: qemu-system-x86 Not tainted 5.9.0 #137
  Hardware name: Gigabyte Technology Co., Ltd. X570 AORUS PRO/X570 AORUS PRO, BIOS F21 07/31/2020
  RIP: 0010:page_counter_uncharge+0x4b/0x50
  ...
  Call Trace:
    hugetlb_cgroup_uncharge_file_region+0x4b/0x80
    region_del+0x1d3/0x300
    hugetlb_unreserve_pages+0x39/0xb0
    remove_inode_hugepages+0x1a8/0x3d0
    hugetlbfs_fallocate+0x3c4/0x5c0
    vfs_fallocate+0x146/0x290
    __x64_sys_fallocate+0x3e/0x70
    do_syscall_64+0x33/0x40
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

Investigation of the issue uncovered bugs in hugetlb cgroup reservation
accounting.  This patch addresses the found issues.

Fixes: 075a61d07a ("hugetlb_cgroup: add accounting for shared mappings")
Reported-by: Michal Privoznik <mprivozn@redhat.com>
Co-developed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Mina Almasry <almasrymina@google.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: <stable@vger.kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Link: https://lkml.kernel.org/r/20201021204426.36069-1-mike.kravetz@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-02 12:14:18 -08:00
Ralph Campbell 46b1ee38b2 mm/mremap_pages: fix static key devmap_managed_key updates
commit 6f42193fd8 ("memremap: don't use a separate devm action for
devmap_managed_enable_get") changed the static key updates such that we
now call devmap_managed_enable_put() without doing the equivalent
devmap_managed_enable_get().

devmap_managed_enable_get() is only called for MEMORY_DEVICE_PRIVATE and
MEMORY_DEVICE_FS_DAX, But memunmap_pages() get called for other pgmap
types too.  This results in the below warning when switching between
system-ram and devdax mode for devdax namespace.

   jump label: negative count!
   WARNING: CPU: 52 PID: 1335 at kernel/jump_label.c:235 static_key_slow_try_dec+0x88/0xa0
   Modules linked in:
   ....

   NIP static_key_slow_try_dec+0x88/0xa0
   LR static_key_slow_try_dec+0x84/0xa0
   Call Trace:
     static_key_slow_try_dec+0x84/0xa0
     __static_key_slow_dec_cpuslocked+0x34/0xd0
     static_key_slow_dec+0x54/0xf0
     memunmap_pages+0x36c/0x500
     devm_action_release+0x30/0x50
     release_nodes+0x2f4/0x3e0
     device_release_driver_internal+0x17c/0x280
     bus_remove_device+0x124/0x210
     device_del+0x1d4/0x530
     unregister_dev_dax+0x48/0xe0
     devm_action_release+0x30/0x50
     release_nodes+0x2f4/0x3e0
     device_release_driver_internal+0x17c/0x280
     unbind_store+0x130/0x170
     drv_attr_store+0x40/0x60
     sysfs_kf_write+0x6c/0xb0
     kernfs_fop_write+0x118/0x280
     vfs_write+0xe8/0x2a0
     ksys_write+0x84/0x140
     system_call_exception+0x120/0x270
     system_call_common+0xf0/0x27c

Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Link: https://lkml.kernel.org/r/20201023183222.13186-1-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-02 12:14:18 -08:00
Dennis Zhou 61cf93d3e1 percpu: convert flexible array initializers to use struct_size()
Use the safer macro as sparked by the long discussion in [1].

[1] https://lore.kernel.org/lkml/20200917204514.GA2880159@google.com/

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
2020-10-30 23:02:28 +00:00
Geert Uytterhoeven f78f63da91 mm/process_vm_access: Add missing #include <linux/compat.h>
With e.g. m68k/defconfig:

    mm/process_vm_access.c: In function ‘process_vm_rw’:
    mm/process_vm_access.c:277:5: error: implicit declaration of function ‘in_compat_syscall’ [-Werror=implicit-function-declaration]
      277 |     in_compat_syscall());
	  |     ^~~~~~~~~~~~~~~~~

Fix this by adding #include <linux/compat.h>.

Reported-by: noreply@ellerman.id.au
Reported-by: damian <damian.tometzki@familie-tometzki.de>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Fixes: 38dc5079da ("Fix compat regression in process_vm_rw()")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-27 12:41:29 -07:00
Jens Axboe 38dc5079da Fix compat regression in process_vm_rw()
The removal of compat_process_vm_{readv,writev} didn't change
process_vm_rw(), which always assumes it's not doing a compat syscall.

Instead of passing in 'false' unconditionally for 'compat', make it
conditional on in_compat_syscall().

[ Both Al and Christoph point out that trying to access a 64-bit process
  from a 32-bit one cannot work anyway, and is likely better prohibited,
  but that's a separate issue    - Linus ]

Fixes: c3973b401e ("mm: remove compat_process_vm_{readv,writev}")
Reported-and-tested-by: Kyle Huey <me@kylehuey.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-27 09:57:46 -07:00
Linus Torvalds c4728cfbed Refactored code for 5.10:
- Move the file range remap generic functions out of mm/filemap.c and
 fs/read_write.c and into fs/remap_range.c to reduce clutter in the first
 two files.
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Merge tag 'vfs-5.10-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull clone/dedupe/remap code refactoring from Darrick Wong:
 "Move the generic file range remap (aka reflink and dedupe) functions
  out of mm/filemap.c and fs/read_write.c and into fs/remap_range.c to
  reduce clutter in the first two files"

* tag 'vfs-5.10-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  vfs: move the generic write and copy checks out of mm
  vfs: move the remap range helpers to remap_range.c
  vfs: move generic_remap_checks out of mm
2020-10-23 11:33:41 -07:00
Linus Torvalds c4d6fe7311 XArray updates for 5.9
- Fix the test suite after introduction of the local_lock
  - Fix a bug in the IDA spotted by Coverity
  - Change the API that allows the workingset code to delete a node
  - Fix xas_reload() when dealing with entries that occupy multiple indices
  - Add a few more tests to the test suite
  - Fix an unsigned int being shifted into an unsigned long
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Merge tag 'xarray-5.9' of git://git.infradead.org/users/willy/xarray

Pull XArray updates from Matthew Wilcox:

 - Fix the test suite after introduction of the local_lock

 - Fix a bug in the IDA spotted by Coverity

 - Change the API that allows the workingset code to delete a node

 - Fix xas_reload() when dealing with entries that occupy multiple
   indices

 - Add a few more tests to the test suite

 - Fix an unsigned int being shifted into an unsigned long

* tag 'xarray-5.9' of git://git.infradead.org/users/willy/xarray:
  XArray: Fix xas_create_range for ranges above 4 billion
  radix-tree: fix the comment of radix_tree_next_slot()
  XArray: Fix xas_reload for multi-index entries
  XArray: Add private interface for workingset node deletion
  XArray: Fix xas_for_each_conflict documentation
  XArray: Test marked multiorder iterations
  XArray: Test two more things about xa_cmpxchg
  ida: Free allocated bitmap in error path
  radix tree test suite: Fix compilation
2020-10-20 14:39:37 -07:00
Linus Torvalds 4962a85696 io_uring-5.10-2020-10-20
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Merge tag 'io_uring-5.10-2020-10-20' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:
 "A mix of fixes and a few stragglers. In detail:

   - Revert the bogus __read_mostly that we discussed for the initial
     pull request.

   - Fix a merge window regression with fixed file registration error
     path handling.

   - Fix io-wq numa node affinities.

   - Series abstracting out an io_identity struct, making it both easier
     to see what the personality items are, and also easier to to adopt
     more. Use this to cover audit logging.

   - Fix for read-ahead disabled block condition in async buffered
     reads, and using single page read-ahead to unify what
     generic_file_buffer_read() path is used.

   - Series for REQ_F_COMP_LOCKED fix and removal of it (Pavel)

   - Poll fix (Pavel)"

* tag 'io_uring-5.10-2020-10-20' of git://git.kernel.dk/linux-block: (21 commits)
  io_uring: use blk_queue_nowait() to check if NOWAIT supported
  mm: use limited read-ahead to satisfy read
  mm: mark async iocb read as NOWAIT once some data has been copied
  io_uring: fix double poll mask init
  io-wq: inherit audit loginuid and sessionid
  io_uring: use percpu counters to track inflight requests
  io_uring: assign new io_identity for task if members have changed
  io_uring: store io_identity in io_uring_task
  io_uring: COW io_identity on mismatch
  io_uring: move io identity items into separate struct
  io_uring: rely solely on work flags to determine personality.
  io_uring: pass required context in as flags
  io-wq: assign NUMA node locality if appropriate
  io_uring: fix error path cleanup in io_sqe_files_register()
  Revert "io_uring: mark io_uring_fops/io_op_defs as __read_mostly"
  io_uring: fix REQ_F_COMP_LOCKED by killing it
  io_uring: dig out COMP_LOCK from deep call chain
  io_uring: don't put a poll req under spinlock
  io_uring: don't unnecessarily clear F_LINK_TIMEOUT
  io_uring: don't set COMP_LOCKED if won't put
  ...
2020-10-20 13:19:30 -07:00
Christoph Hellwig b71df8de41 mm: remove the filename in the top of file comment in vmalloc.c
No point in having the filename inside the file.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Link: https://lkml.kernel.org/r/20201002124035.1539300-3-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:10 -07:00
Christoph Hellwig f255935b97 mm: cleanup the gfp_mask handling in __vmalloc_area_node
Patch series "two small vmalloc cleanups".

This patch (of 2):

__vmalloc_area_node currently has four different gfp_t variables to
just express this simple logic:

 - use the passed in mask, plus __GFP_NOWARN and __GFP_HIGHMEM (if
   suitable) for the underlying page allocation
 - use just the reclaim flags from the passed in mask plus __GFP_ZERO
   for allocating the page array

Simplify this down to just use the pre-existing nested_gfp as-is for
the page array allocation, and just the passed in gfp_mask for the
page allocation, after conditionally ORing __GFP_HIGHMEM into it.  This
also makes the allocation warning a little more correct.

Also initialize two variables at the time of declaration while touching
this area.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Link: https://lkml.kernel.org/r/20201002124035.1539300-1-hch@lst.de
Link: https://lkml.kernel.org/r/20201002124035.1539300-2-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:10 -07:00
Christoph Hellwig 301fa9f2dd mm: remove alloc_vm_area
All users are gone now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Link: https://lkml.kernel.org/r/20201002122204.1534411-12-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:10 -07:00
Christoph Hellwig d1b6d2e1fe zsmalloc: switch from alloc_vm_area to get_vm_area
Just manually pre-fault the PTEs using apply_to_page_range.

Co-developed-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Link: https://lkml.kernel.org/r/20201002122204.1534411-6-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:10 -07:00
Christoph Hellwig eeb4a05fce mm: allow a NULL fn callback in apply_to_page_range
Besides calling the callback on each page, apply_to_page_range also has
the effect of pre-faulting all PTEs for the range.  To support callers
that only need the pre-faulting, make the callback optional.

Based on a patch from Minchan Kim <minchan@kernel.org>.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Link: https://lkml.kernel.org/r/20201002122204.1534411-5-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:10 -07:00
Christoph Hellwig 3e9a9e256b mm: add a vmap_pfn function
Add a proper helper to remap PFNs into kernel virtual space so that
drivers don't have to abuse alloc_vm_area and open coded PTE manipulation
for it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Link: https://lkml.kernel.org/r/20201002122204.1534411-4-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:10 -07:00
Christoph Hellwig b944afc9d6 mm: add a VM_MAP_PUT_PAGES flag for vmap
Add a flag so that vmap takes ownership of the passed in page array.  When
vfree is called on such an allocation it will put one reference on each
page, and free the page array itself.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Link: https://lkml.kernel.org/r/20201002122204.1534411-3-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:10 -07:00
Matthew Wilcox (Oracle) fa307474c6 mm: update the documentation for vfree
Patch series "remove alloc_vm_area", v4.

This series removes alloc_vm_area, which was left over from the big
vmalloc interface rework.  It is a rather arkane interface, basicaly the
equivalent of get_vm_area + actually faulting in all PTEs in the allocated
area.  It was originally addeds for Xen (which isn't modular to start
with), and then grew users in zsmalloc and i915 which seems to mostly
qualify as abuses of the interface, especially for i915 as a random driver
should not set up PTE bits directly.

This patch (of 11):

 * Document that you can call vfree() on an address returned from vmap()
 * Remove the note about the minimum size -- the minimum size of a vmalloc
   allocation is one page
 * Add a Context: section
 * Fix capitalisation
 * Reword the prohibition on calling from NMI context to avoid a double
   negative

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Link: https://lkml.kernel.org/r/20201002122204.1534411-1-hch@lst.de
Link: https://lkml.kernel.org/r/20201002122204.1534411-2-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:10 -07:00
Minchan Kim ecb8ac8b1f mm/madvise: introduce process_madvise() syscall: an external memory hinting API
There is usecase that System Management Software(SMS) want to give a
memory hint like MADV_[COLD|PAGEEOUT] to other processes and in the
case of Android, it is the ActivityManagerService.

The information required to make the reclaim decision is not known to the
app.  Instead, it is known to the centralized userspace
daemon(ActivityManagerService), and that daemon must be able to initiate
reclaim on its own without any app involvement.

To solve the issue, this patch introduces a new syscall
process_madvise(2).  It uses pidfd of an external process to give the
hint.  It also supports vector address range because Android app has
thousands of vmas due to zygote so it's totally waste of CPU and power if
we should call the syscall one by one for each vma.(With testing 2000-vma
syscall vs 1-vector syscall, it showed 15% performance improvement.  I
think it would be bigger in real practice because the testing ran very
cache friendly environment).

Another potential use case for the vector range is to amortize the cost
ofTLB shootdowns for multiple ranges when using MADV_DONTNEED; this could
benefit users like TCP receive zerocopy and malloc implementations.  In
future, we could find more usecases for other advises so let's make it
happens as API since we introduce a new syscall at this moment.  With
that, existing madvise(2) user could replace it with process_madvise(2)
with their own pid if they want to have batch address ranges support
feature.

ince it could affect other process's address range, only privileged
process(PTRACE_MODE_ATTACH_FSCREDS) or something else(e.g., being the same
UID) gives it the right to ptrace the process could use it successfully.
The flag argument is reserved for future use if we need to extend the API.

I think supporting all hints madvise has/will supported/support to
process_madvise is rather risky.  Because we are not sure all hints make
sense from external process and implementation for the hint may rely on
the caller being in the current context so it could be error-prone.  Thus,
I just limited hints as MADV_[COLD|PAGEOUT] in this patch.

If someone want to add other hints, we could hear the usecase and review
it for each hint.  It's safer for maintenance rather than introducing a
buggy syscall but hard to fix it later.

So finally, the API is as follows,

      ssize_t process_madvise(int pidfd, const struct iovec *iovec,
                unsigned long vlen, int advice, unsigned int flags);

    DESCRIPTION
      The process_madvise() system call is used to give advice or directions
      to the kernel about the address ranges from external process as well as
      local process. It provides the advice to address ranges of process
      described by iovec and vlen. The goal of such advice is to improve
      system or application performance.

      The pidfd selects the process referred to by the PID file descriptor
      specified in pidfd. (See pidofd_open(2) for further information)

      The pointer iovec points to an array of iovec structures, defined in
      <sys/uio.h> as:

        struct iovec {
            void *iov_base;         /* starting address */
            size_t iov_len;         /* number of bytes to be advised */
        };

      The iovec describes address ranges beginning at address(iov_base)
      and with size length of bytes(iov_len).

      The vlen represents the number of elements in iovec.

      The advice is indicated in the advice argument, which is one of the
      following at this moment if the target process specified by pidfd is
      external.

        MADV_COLD
        MADV_PAGEOUT

      Permission to provide a hint to external process is governed by a
      ptrace access mode PTRACE_MODE_ATTACH_FSCREDS check; see ptrace(2).

      The process_madvise supports every advice madvise(2) has if target
      process is in same thread group with calling process so user could
      use process_madvise(2) to extend existing madvise(2) to support
      vector address ranges.

    RETURN VALUE
      On success, process_madvise() returns the number of bytes advised.
      This return value may be less than the total number of requested
      bytes, if an error occurred. The caller should check return value
      to determine whether a partial advice occurred.

FAQ:

Q.1 - Why does any external entity have better knowledge?

Quote from Sandeep

"For Android, every application (including the special SystemServer)
are forked from Zygote.  The reason of course is to share as many
libraries and classes between the two as possible to benefit from the
preloading during boot.

After applications start, (almost) all of the APIs end up calling into
this SystemServer process over IPC (binder) and back to the
application.

In a fully running system, the SystemServer monitors every single
process periodically to calculate their PSS / RSS and also decides
which process is "important" to the user for interactivity.

So, because of how these processes start _and_ the fact that the
SystemServer is looping to monitor each process, it does tend to *know*
which address range of the application is not used / useful.

Besides, we can never rely on applications to clean things up
themselves.  We've had the "hey app1, the system is low on memory,
please trim your memory usage down" notifications for a long time[1].
They rely on applications honoring the broadcasts and very few do.

So, if we want to avoid the inevitable killing of the application and
restarting it, some way to be able to tell the OS about unimportant
memory in these applications will be useful.

- ssp

Q.2 - How to guarantee the race(i.e., object validation) between when
giving a hint from an external process and get the hint from the target
process?

process_madvise operates on the target process's address space as it
exists at the instant that process_madvise is called.  If the space
target process can run between the time the process_madvise process
inspects the target process address space and the time that
process_madvise is actually called, process_madvise may operate on
memory regions that the calling process does not expect.  It's the
responsibility of the process calling process_madvise to close this
race condition.  For example, the calling process can suspend the
target process with ptrace, SIGSTOP, or the freezer cgroup so that it
doesn't have an opportunity to change its own address space before
process_madvise is called.  Another option is to operate on memory
regions that the caller knows a priori will be unchanged in the target
process.  Yet another option is to accept the race for certain
process_madvise calls after reasoning that mistargeting will do no
harm.  The suggested API itself does not provide synchronization.  It
also apply other APIs like move_pages, process_vm_write.

The race isn't really a problem though.  Why is it so wrong to require
that callers do their own synchronization in some manner?  Nobody
objects to write(2) merely because it's possible for two processes to
open the same file and clobber each other's writes --- instead, we tell
people to use flock or something.  Think about mmap.  It never
guarantees newly allocated address space is still valid when the user
tries to access it because other threads could unmap the memory right
before.  That's where we need synchronization by using other API or
design from userside.  It shouldn't be part of API itself.  If someone
needs more fine-grained synchronization rather than process level,
there were two ideas suggested - cookie[2] and anon-fd[3].  Both are
applicable via using last reserved argument of the API but I don't
think it's necessary right now since we have already ways to prevent
the race so don't want to add additional complexity with more
fine-grained optimization model.

To make the API extend, it reserved an unsigned long as last argument
so we could support it in future if someone really needs it.

Q.3 - Why doesn't ptrace work?

Injecting an madvise in the target process using ptrace would not work
for us because such injected madvise would have to be executed by the
target process, which means that process would have to be runnable and
that creates the risk of the abovementioned race and hinting a wrong
VMA.  Furthermore, we want to act the hint in caller's context, not the
callee's, because the callee is usually limited in cpuset/cgroups or
even freezed state so they can't act by themselves quick enough, which
causes more thrashing/kill.  It doesn't work if the target process are
ptraced(e.g., strace, debugger, minidump) because a process can have at
most one ptracer.

[1] https://developer.android.com/topic/performance/memory"

[2] process_getinfo for getting the cookie which is updated whenever
    vma of process address layout are changed - Daniel Colascione -
    https://lore.kernel.org/lkml/20190520035254.57579-1-minchan@kernel.org/T/#m7694416fd179b2066a2c62b5b139b14e3894e224

[3] anonymous fd which is used for the object(i.e., address range)
    validation - Michal Hocko -
    https://lore.kernel.org/lkml/20200120112722.GY18451@dhcp22.suse.cz/

[minchan@kernel.org: fix process_madvise build break for arm64]
  Link: http://lkml.kernel.org/r/20200303145756.GA219683@google.com
[minchan@kernel.org: fix build error for mips of process_madvise]
  Link: http://lkml.kernel.org/r/20200508052517.GA197378@google.com
[akpm@linux-foundation.org: fix patch ordering issue]
[akpm@linux-foundation.org: fix arm64 whoops]
[minchan@kernel.org: make process_madvise() vlen arg have type size_t, per Florian]
[akpm@linux-foundation.org: fix i386 build]
[sfr@canb.auug.org.au: fix syscall numbering]
  Link: https://lkml.kernel.org/r/20200905142639.49fc3f1a@canb.auug.org.au
[sfr@canb.auug.org.au: madvise.c needs compat.h]
  Link: https://lkml.kernel.org/r/20200908204547.285646b4@canb.auug.org.au
[minchan@kernel.org: fix mips build]
  Link: https://lkml.kernel.org/r/20200909173655.GC2435453@google.com
[yuehaibing@huawei.com: remove duplicate header which is included twice]
  Link: https://lkml.kernel.org/r/20200915121550.30584-1-yuehaibing@huawei.com
[minchan@kernel.org: do not use helper functions for process_madvise]
  Link: https://lkml.kernel.org/r/20200921175539.GB387368@google.com
[akpm@linux-foundation.org: pidfd_get_pid() gained an argument]
[sfr@canb.auug.org.au: fix up for "iov_iter: transparently handle compat iovecs in import_iovec"]
  Link: https://lkml.kernel.org/r/20200928212542.468e1fef@canb.auug.org.au

Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <christian@brauner.io>
Cc: Daniel Colascione <dancol@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Dias <joaodias@google.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oleksandr Natalenko <oleksandr@redhat.com>
Cc: Sandeep Patil <sspatil@google.com>
Cc: SeongJae Park <sj38.park@gmail.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sonny Rao <sonnyrao@google.com>
Cc: Tim Murray <timmurray@google.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Florian Weimer <fw@deneb.enyo.de>
Cc: <linux-man@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200302193630.68771-3-minchan@kernel.org
Link: http://lkml.kernel.org/r/20200508183320.GA125527@google.com
Link: http://lkml.kernel.org/r/20200622192900.22757-4-minchan@kernel.org
Link: https://lkml.kernel.org/r/20200901000633.1920247-4-minchan@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:10 -07:00
Minchan Kim 0726b01e70 mm/madvise: pass mm to do_madvise
Patch series "introduce memory hinting API for external process", v9.

Now, we have MADV_PAGEOUT and MADV_COLD as madvise hinting API.  With
that, application could give hints to kernel what memory range are
preferred to be reclaimed.  However, in some platform(e.g., Android), the
information required to make the hinting decision is not known to the app.
Instead, it is known to a centralized userspace daemon(e.g.,
ActivityManagerService), and that daemon must be able to initiate reclaim
on its own without any app involvement.

To solve the concern, this patch introduces new syscall -
process_madvise(2).  Bascially, it's same with madvise(2) syscall but it
has some differences.

1. It needs pidfd of target process to provide the hint

2. It supports only MADV_{COLD|PAGEOUT|MERGEABLE|UNMEREABLE} at this
   moment.  Other hints in madvise will be opened when there are explicit
   requests from community to prevent unexpected bugs we couldn't support.

3. Only privileged processes can do something for other process's
   address space.

For more detail of the new API, please see "mm: introduce external memory
hinting API" description in this patchset.

This patch (of 3):

In upcoming patches, do_madvise will be called from external process
context so we shouldn't asssume "current" is always hinted process's
task_struct.

Furthermore, we must not access mm_struct via task->mm, but obtain it via
access_mm() once (in the following patch) and only use that pointer [1],
so pass it to do_madvise() as well.  Note the vma->vm_mm pointers are
safe, so we can use them further down the call stack.

And let's pass current->mm as arguments of do_madvise so it shouldn't
change existing behavior but prepare next patch to make review easy.

[vbabka@suse.cz: changelog tweak]
[minchan@kernel.org: use current->mm for io_uring]
  Link: http://lkml.kernel.org/r/20200423145215.72666-1-minchan@kernel.org
[akpm@linux-foundation.org: fix it for upstream changes]
[akpm@linux-foundation.org: whoops]
[rdunlap@infradead.org: add missing includes]

Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jann Horn <jannh@google.com>
Cc: Tim Murray <timmurray@google.com>
Cc: Daniel Colascione <dancol@google.com>
Cc: Sandeep Patil <sspatil@google.com>
Cc: Sonny Rao <sonnyrao@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: John Dias <joaodias@google.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: SeongJae Park <sj38.park@gmail.com>
Cc: Christian Brauner <christian@brauner.io>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Oleksandr Natalenko <oleksandr@redhat.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Florian Weimer <fw@deneb.enyo.de>
Cc: <linux-man@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200901000633.1920247-1-minchan@kernel.org
Link: http://lkml.kernel.org/r/20200622192900.22757-1-minchan@kernel.org
Link: http://lkml.kernel.org/r/20200302193630.68771-2-minchan@kernel.org
Link: http://lkml.kernel.org/r/20200622192900.22757-2-minchan@kernel.org
Link: https://lkml.kernel.org/r/20200901000633.1920247-2-minchan@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:09 -07:00
Jann Horn f3964599c2 mm/gup_benchmark: take the mmap lock around GUP
To be safe against concurrent changes to the VMA tree, we must take the
mmap lock around GUP operations (excluding the GUP-fast family of
operations, which will take the mmap lock by themselves if necessary).

This code is only for testing, and it's only reachable by root through
debugfs, so this doesn't really have any impact; however, if we want to
add lockdep asserts into the GUP path, we need to have clean locking here.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Michel Lespinasse <walken@google.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Link: https://lkml.kernel.org/r/CAG48ez3SG6ngZLtasxJ6LABpOnqCz5-QHqb0B4k44TQ8F9n6+w@mail.gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:09 -07:00
Liam R. Howlett fb8090b699 mm/mmap: add inline munmap_vma_range() for code readability
There are two locations that have a block of code for munmapping a vma
range.  Change those two locations to use a function and add meaningful
comments about what happens to the arguments, which was unclear in the
previous code.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200818154707.2515169-2-Liam.Howlett@Oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:09 -07:00
Liam R. Howlett 3903b55a61 mm/mmap: add inline vma_next() for readability of mmap code
There are three places that the next vma is required which uses the same
block of code.  Replace the block with a function and add comments on what
happens in the case where NULL is encountered.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200818154707.2515169-1-Liam.Howlett@Oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:09 -07:00
Miaohe Lin 4dc200cee1 mm/migrate: avoid possible unnecessary process right check in kernel_move_pages()
There is no need to check if this process has the right to modify the
specified process when they are same.  And we could also skip the security
hook call if a process is modifying its own pages.  Add helper function to
handle these.

Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Hongxiang Lou <louhongxiang@huawei.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christopher Lameter <cl@linux.com>
Link: https://lkml.kernel.org/r/20200819083331.19012-1-linmiaohe@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:09 -07:00
Joonsoo Kim 203e6e5ca4 mm/memory_hotplug: remove a wrapper for alloc_migration_target()
To calculate the correct node to migrate the page for hotplug, we need to
check node id of the page.  Wrapper for alloc_migration_target() exists
for this purpose.

However, Vlastimil informs that all migration source pages come from a
single node.  In this case, we don't need to check the node id for each
page and we don't need to re-set the target nodemask for each page by
using the wrapper.  Set up the migration_target_control once and use it
for all pages.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-10-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:09 -07:00
Joonsoo Kim 5460875999 mm/memory-failure: remove a wrapper for alloc_migration_target()
There is a well-defined standard migration target callback.  Use it
directly.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-9-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:09 -07:00
Roman Gushchin 4127c6504f mm: kmem: enable kernel memcg accounting from interrupt contexts
If a memcg to charge can be determined (using remote charging API), there
are no reasons to exclude allocations made from an interrupt context from
the accounting.

Such allocations will pass even if the resulting memcg size will exceed
the hard limit, but it will affect the application of the memory pressure
and an inability to put the workload under the limit will eventually
trigger the OOM.

To use active_memcg() helper, memcg_kmem_bypass() is moved back to
memcontrol.c.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Link: http://lkml.kernel.org/r/20200827225843.1270629-5-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:09 -07:00
Roman Gushchin 37d5985c00 mm: kmem: prepare remote memcg charging infra for interrupt contexts
Remote memcg charging API uses current->active_memcg to store the
currently active memory cgroup, which overwrites the memory cgroup of the
current process.  It works well for normal contexts, but doesn't work for
interrupt contexts: indeed, if an interrupt occurs during the execution of
a section with an active memcg set, all allocations inside the interrupt
will be charged to the active memcg set (given that we'll enable
accounting for allocations from an interrupt context).  But because the
interrupt might have no relation to the active memcg set outside, it's
obviously wrong from the accounting prospective.

To resolve this problem, let's add a global percpu int_active_memcg
variable, which will be used to store an active memory cgroup which will
be used from interrupt contexts.  set_active_memcg() will transparently
use current->active_memcg or int_active_memcg depending on the context.

To make the read part simple and transparent for the caller, let's
introduce two new functions:
  - struct mem_cgroup *active_memcg(void),
  - struct mem_cgroup *get_active_memcg(void).

They are returning the active memcg if it's set, hiding all implementation
details: where to get it depending on the current context.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Link: http://lkml.kernel.org/r/20200827225843.1270629-4-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:09 -07:00
Roman Gushchin 67f0286498 mm: kmem: remove redundant checks from get_obj_cgroup_from_current()
There are checks for current->mm and current->active_memcg in
get_obj_cgroup_from_current(), but these checks are redundant:
memcg_kmem_bypass() called just above performs same checks.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Link: http://lkml.kernel.org/r/20200827225843.1270629-3-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:09 -07:00
Roman Gushchin 279c3393e2 mm: kmem: move memcg_kmem_bypass() calls to get_mem/obj_cgroup_from_current()
Patch series "mm: kmem: kernel memory accounting in an interrupt context".

This patchset implements memcg-based memory accounting of allocations made
from an interrupt context.

Historically, such allocations were passed unaccounted mostly because
charging the memory cgroup of the current process wasn't an option.  Also
performance reasons were likely a reason too.

The remote charging API allows to temporarily overwrite the currently
active memory cgroup, so that all memory allocations are accounted towards
some specified memory cgroup instead of the memory cgroup of the current
process.

This patchset extends the remote charging API so that it can be used from
an interrupt context.  Then it removes the fence that prevented the
accounting of allocations made from an interrupt context.  It also
contains a couple of optimizations/code refactorings.

This patchset doesn't directly enable accounting for any specific
allocations, but prepares the code base for it.  The bpf memory accounting
will likely be the first user of it: a typical example is a bpf program
parsing an incoming network packet, which allocates an entry in hashmap
map to store some information.

This patch (of 4):

Currently memcg_kmem_bypass() is called before obtaining the current
memory/obj cgroup using get_mem/obj_cgroup_from_current().  Moving
memcg_kmem_bypass() into get_mem/obj_cgroup_from_current() reduces the
number of call sites and allows further code simplifications.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Link: http://lkml.kernel.org/r/20200827225843.1270629-1-guro@fb.com
Link: http://lkml.kernel.org/r/20200827225843.1270629-2-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:09 -07:00
Roman Gushchin b87d8cefe4 mm, memcg: rework remote charging API to support nesting
Currently the remote memcg charging API consists of two functions:
memalloc_use_memcg() and memalloc_unuse_memcg(), which set and clear the
memcg value, which overwrites the memcg of the current task.

  memalloc_use_memcg(target_memcg);
  <...>
  memalloc_unuse_memcg();

It works perfectly for allocations performed from a normal context,
however an attempt to call it from an interrupt context or just nest two
remote charging blocks will lead to an incorrect accounting.  On exit from
the inner block the active memcg will be cleared instead of being
restored.

  memalloc_use_memcg(target_memcg);

  memalloc_use_memcg(target_memcg_2);
    <...>
    memalloc_unuse_memcg();

    Error: allocation here are charged to the memcg of the current
    process instead of target_memcg.

  memalloc_unuse_memcg();

This patch extends the remote charging API by switching to a single
function: struct mem_cgroup *set_active_memcg(struct mem_cgroup *memcg),
which sets the new value and returns the old one.  So a remote charging
block will look like:

  old_memcg = set_active_memcg(target_memcg);
  <...>
  set_active_memcg(old_memcg);

This patch is heavily based on the patch by Johannes Weiner, which can be
found here: https://lkml.org/lkml/2020/5/28/806 .

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dan Schatzberg <dschatzberg@fb.com>
Link: https://lkml.kernel.org/r/20200821212056.3769116-1-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:09 -07:00
Jens Axboe 324bcf54c4 mm: use limited read-ahead to satisfy read
For the case where read-ahead is disabled on the file, or if the cgroup
is congested, ensure that we can at least do 1 page of read-ahead to
make progress on the read in an async fashion. This could potentially be
larger, but it's not needed in terms of functionality, so let's error on
the side of caution as larger counts of pages may run into reclaim
issues (particularly if we're congested).

This makes sure we're not hitting the potentially sync ->readpage() path
for IO that is marked IOCB_WAITQ, which could cause us to block. It also
means we'll use the same path for IO, regardless of whether or not
read-ahead happens to be disabled on the lower level device.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: Hao_Xu <haoxu@linux.alibaba.com>
[axboe: updated for new ractl API]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 13:49:08 -06:00
Jens Axboe 13bd691421 mm: mark async iocb read as NOWAIT once some data has been copied
Once we've copied some data for an iocb that is marked with IOCB_WAITQ,
we should no longer attempt to async lock a new page. Instead make sure
we return the copied amount, and let the caller retry, instead of
returning -EIOCBQUEUED for a new page.

This should only be possible with read-ahead disabled on the below
device, and multiple threads racing on the same file. Haven't been able
to reproduce on anything else.

Cc: stable@vger.kernel.org # v5.9
Fixes: 1a0a7853b9 ("mm: support async buffered reads in generic_file_buffered_read()")
Reported-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 13:49:05 -06:00
Linus Torvalds 54a4c789ca docs updates for v5.10-rc1
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Merge tag 'docs/v5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media

Pull documentation updates from Mauro Carvalho Chehab:
 "A series of patches addressing warnings produced by make htmldocs.
  This includes:

   - kernel-doc markup fixes

   - ReST fixes

   - Updates at the build system in order to support newer versions of
     the docs build toolchain (Sphinx)

  After this series, the number of html build warnings should reduce
  significantly, and building with Sphinx 3.1 or later should now be
  supported (although it is still recommended to use Sphinx 2.4.4).

  As agreed with Jon, I should be sending you a late pull request by the
  end of the merge window addressing remaining issues with docs build,
  as there are a number of warning fixes that depends on pull requests
  that should be happening along the merge window.

  The end goal is to have a clean htmldocs build on Kernel 5.10.

  PS. It should be noticed that Sphinx 3.0 is not currently supported,
  as it lacks support for C domain namespaces. Such feature, needed in
  order to document uAPI system calls with Sphinx 3.x, was added only on
  Sphinx 3.1"

* tag 'docs/v5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (75 commits)
  PM / devfreq: remove a duplicated kernel-doc markup
  mm/doc: fix a literal block markup
  workqueue: fix a kernel-doc warning
  docs: virt: user_mode_linux_howto_v2.rst: fix a literal block markup
  Input: sparse-keymap: add a description for @sw
  rcu/tree: docs: document bkvcache new members at struct kfree_rcu_cpu
  nl80211: docs: add a description for s1g_cap parameter
  usb: docs: document altmode register/unregister functions
  kunit: test.h: fix a bad kernel-doc markup
  drivers: core: fix kernel-doc markup for dev_err_probe()
  docs: bio: fix a kerneldoc markup
  kunit: test.h: solve kernel-doc warnings
  block: bio: fix a warning at the kernel-doc markups
  docs: powerpc: syscall64-abi.rst: fix a malformed table
  drivers: net: hamradio: fix document location
  net: appletalk: Kconfig: Fix docs location
  dt-bindings: fix references to files converted to yaml
  memblock: get rid of a :c:type leftover
  math64.h: kernel-docs: Convert some markups into normal comments
  media: uAPI: buffer.rst: remove a left-over documentation
  ...
2020-10-16 15:02:21 -07:00
Linus Torvalds c4cf498dc0 Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:
 "155 patches.

  Subsystems affected by this patch series: mm (dax, debug, thp,
  readahead, page-poison, util, memory-hotplug, zram, cleanups), misc,
  core-kernel, get_maintainer, MAINTAINERS, lib, bitops, checkpatch,
  binfmt, ramfs, autofs, nilfs, rapidio, panic, relay, kgdb, ubsan,
  romfs, and fault-injection"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (155 commits)
  lib, uaccess: add failure injection to usercopy functions
  lib, include/linux: add usercopy failure capability
  ROMFS: support inode blocks calculation
  ubsan: introduce CONFIG_UBSAN_LOCAL_BOUNDS for Clang
  sched.h: drop in_ubsan field when UBSAN is in trap mode
  scripts/gdb/tasks: add headers and improve spacing format
  scripts/gdb/proc: add struct mount & struct super_block addr in lx-mounts command
  kernel/relay.c: drop unneeded initialization
  panic: dump registers on panic_on_warn
  rapidio: fix the missed put_device() for rio_mport_add_riodev
  rapidio: fix error handling path
  nilfs2: fix some kernel-doc warnings for nilfs2
  autofs: harden ioctl table
  ramfs: fix nommu mmap with gaps in the page cache
  mm: remove the now-unnecessary mmget_still_valid() hack
  mm/gup: take mmap_lock in get_dump_page()
  binfmt_elf, binfmt_elf_fdpic: use a VMA list snapshot
  coredump: rework elf/elf_fdpic vma_dump_size() into common helper
  coredump: refactor page range dumping into common helper
  coredump: let dump_emit() bail out on short writes
  ...
2020-10-16 11:31:55 -07:00
Jann Horn 4d45e75a99 mm: remove the now-unnecessary mmget_still_valid() hack
The preceding patches have ensured that core dumping properly takes the
mmap_lock.  Thanks to that, we can now remove mmget_still_valid() and all
its users.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200827114932.3572699-8-jannh@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-16 11:11:22 -07:00
Jann Horn 7f3bfab52c mm/gup: take mmap_lock in get_dump_page()
Properly take the mmap_lock before calling into the GUP code from
get_dump_page(); and play nice, allowing the GUP code to drop the
mmap_lock if it has to sleep.

As Linus pointed out, we don't actually need the VMA because
__get_user_pages() will flush the dcache for us if necessary.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200827114932.3572699-7-jannh@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-16 11:11:21 -07:00
Jann Horn 8f942eea12 binfmt_elf_fdpic: stop using dump_emit() on user pointers on !MMU
Patch series "Fix ELF / FDPIC ELF core dumping, and use mmap_lock properly in there", v5.

At the moment, we have that rather ugly mmget_still_valid() helper to work
around <https://crbug.com/project-zero/1790>: ELF core dumping doesn't
take the mmap_sem while traversing the task's VMAs, and if anything (like
userfaultfd) then remotely messes with the VMA tree, fireworks ensue.  So
at the moment we use mmget_still_valid() to bail out in any writers that
might be operating on a remote mm's VMAs.

With this series, I'm trying to get rid of the need for that as cleanly as
possible.  ("cleanly" meaning "avoid holding the mmap_lock across
unbounded sleeps".)

Patches 1, 2, 3 and 4 are relatively unrelated cleanups in the core
dumping code.

Patches 5 and 6 implement the main change: Instead of repeatedly accessing
the VMA list with sleeps in between, we snapshot it at the start with
proper locking, and then later we just use our copy of the VMA list.  This
ensures that the kernel won't crash, that VMA metadata in the coredump is
consistent even in the presence of concurrent modifications, and that any
virtual addresses that aren't being concurrently modified have their
contents show up in the core dump properly.

The disadvantage of this approach is that we need a bit more memory during
core dumping for storing metadata about all VMAs.

At the end of the series, patch 7 removes the old workaround for this
issue (mmget_still_valid()).

I have tested:

 - Creating a simple core dump on X86-64 still works.
 - The created coredump on X86-64 opens in GDB and looks plausible.
 - X86-64 core dumps contain the first page for executable mappings at
   offset 0, and don't contain the first page for non-executable file
   mappings or executable mappings at offset !=0.
 - NOMMU 32-bit ARM can still generate plausible-looking core dumps
   through the FDPIC implementation. (I can't test this with GDB because
   GDB is missing some structure definition for nommu ARM, but I've
   poked around in the hexdump and it looked decent.)

This patch (of 7):

dump_emit() is for kernel pointers, and VMAs describe userspace memory.
Let's be tidy here and avoid accessing userspace pointers under KERNEL_DS,
even if it probably doesn't matter much on !MMU systems - especially given
that it looks like we can just use the same get_dump_page() as on MMU if
we move it out of the CONFIG_MMU block.

One small change we have to make in get_dump_page() is to use
__get_user_pages_locked() instead of __get_user_pages(), since the latter
doesn't exist on nommu.  On mmu builds, __get_user_pages_locked() will
just call __get_user_pages() for us.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200827114932.3572699-1-jannh@google.com
Link: http://lkml.kernel.org/r/20200827114932.3572699-2-jannh@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-16 11:11:21 -07:00
Matthew Wilcox (Oracle) ab130f9108 mm: rename page_order() to buddy_order()
The current page_order() can only be called on pages in the buddy
allocator.  For compound pages, you have to use compound_order().  This is
confusing and led to a bug, so rename page_order() to buddy_order().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20201001152259.14932-2-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-16 11:11:19 -07:00