From 4bb6e96ab808f88d746343637f0cc2243b527da5 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Wed, 27 Jun 2018 23:26:01 -0700 Subject: [PATCH 1/7] lib/percpu_ida.c: don't do alloc from per-CPU list if there is none In commit 804209d8a009 ("lib/percpu_ida.c: use _irqsave() instead of local_irq_save() + spin_lock") I inlined alloc_local_tag() and mixed up the >= check from percpu_ida_alloc() with the one in alloc_local_tag(). Don't alloc from per-CPU freelist if ->nr_free is zero. Link: http://lkml.kernel.org/r/20180613075830.c3zeva52fuj6fxxv@linutronix.de Fixes: 804209d8a009 ("lib/percpu_ida.c: use _irqsave() instead of local_irq_save() + spin_lock") Signed-off-by: Sebastian Andrzej Siewior Reported-by: David Disseldorp Tested-by: David Disseldorp Cc: Thomas Gleixner Cc: Nicholas Bellinger Cc: Shaohua Li Cc: Kent Overstreet Cc: Matthew Wilcox Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/percpu_ida.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/percpu_ida.c b/lib/percpu_ida.c index 9bbd9c5d375a..beb14839b41a 100644 --- a/lib/percpu_ida.c +++ b/lib/percpu_ida.c @@ -141,7 +141,7 @@ int percpu_ida_alloc(struct percpu_ida *pool, int state) spin_lock_irqsave(&tags->lock, flags); /* Fastpath */ - if (likely(tags->nr_free >= 0)) { + if (likely(tags->nr_free)) { tag = tags->freelist[--tags->nr_free]; spin_unlock_irqrestore(&tags->lock, flags); return tag; From 28557cc106e6d2aa8b8c5c7687ea9f8055ff3911 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Wed, 27 Jun 2018 23:26:05 -0700 Subject: [PATCH 2/7] Revert mm/vmstat.c: fix vmstat_update() preemption BUG Revert commit c7f26ccfb2c3 ("mm/vmstat.c: fix vmstat_update() preemption BUG"). Steven saw a "using smp_processor_id() in preemptible" message and added a preempt_disable() section around it to keep it quiet. This is not the right thing to do it does not fix the real problem. vmstat_update() is invoked by a kworker on a specific CPU. This worker it bound to this CPU. The name of the worker was "kworker/1:1" so it should have been a worker which was bound to CPU1. A worker which can run on any CPU would have a `u' before the first digit. smp_processor_id() can be used in a preempt-enabled region as long as the task is bound to a single CPU which is the case here. If it could run on an arbitrary CPU then this is the problem we have an should seek to resolve. Not only this smp_processor_id() must not be migrated to another CPU but also refresh_cpu_vm_stats() which might access wrong per-CPU variables. Not to mention that other code relies on the fact that such a worker runs on one specific CPU only. Therefore revert that commit and we should look instead what broke the affinity mask of the kworker. Link: http://lkml.kernel.org/r/20180504104451.20278-1-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior Cc: Steven J. Hill Cc: Tejun Heo Cc: Vlastimil Babka Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmstat.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/mm/vmstat.c b/mm/vmstat.c index 75eda9c2b260..8ba0870ecddd 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1796,11 +1796,9 @@ static void vmstat_update(struct work_struct *w) * to occur in the future. Keep on running the * update worker thread. */ - preempt_disable(); queue_delayed_work_on(smp_processor_id(), mm_percpu_wq, this_cpu_ptr(&vmstat_work), round_jiffies_relative(sysctl_stat_interval)); - preempt_enable(); } } From d50d82faa0c964e31f7a946ba8aba7c715ca7ab0 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Wed, 27 Jun 2018 23:26:09 -0700 Subject: [PATCH 3/7] slub: fix failure when we delete and create a slab cache In kernel 4.17 I removed some code from dm-bufio that did slab cache merging (commit 21bb13276768: "dm bufio: remove code that merges slab caches") - both slab and slub support merging caches with identical attributes, so dm-bufio now just calls kmem_cache_create and relies on implicit merging. This uncovered a bug in the slub subsystem - if we delete a cache and immediatelly create another cache with the same attributes, it fails because of duplicate filename in /sys/kernel/slab/. The slub subsystem offloads freeing the cache to a workqueue - and if we create the new cache before the workqueue runs, it complains because of duplicate filename in sysfs. This patch fixes the bug by moving the call of kobject_del from sysfs_slab_remove_workfn to shutdown_cache. kobject_del must be called while we hold slab_mutex - so that the sysfs entry is deleted before a cache with the same attributes could be created. Running device-mapper-test-suite with: dmtest run --suite thin-provisioning -n /commit_failure_causes_fallback/ triggered: Buffer I/O error on dev dm-0, logical block 1572848, async page read device-mapper: thin: 253:1: metadata operation 'dm_pool_alloc_data_block' failed: error = -5 device-mapper: thin: 253:1: aborting current metadata transaction sysfs: cannot create duplicate filename '/kernel/slab/:a-0000144' CPU: 2 PID: 1037 Comm: kworker/u48:1 Not tainted 4.17.0.snitm+ #25 Hardware name: Supermicro SYS-1029P-WTR/X11DDW-L, BIOS 2.0a 12/06/2017 Workqueue: dm-thin do_worker [dm_thin_pool] Call Trace: dump_stack+0x5a/0x73 sysfs_warn_dup+0x58/0x70 sysfs_create_dir_ns+0x77/0x80 kobject_add_internal+0xba/0x2e0 kobject_init_and_add+0x70/0xb0 sysfs_slab_add+0xb1/0x250 __kmem_cache_create+0x116/0x150 create_cache+0xd9/0x1f0 kmem_cache_create_usercopy+0x1c1/0x250 kmem_cache_create+0x18/0x20 dm_bufio_client_create+0x1ae/0x410 [dm_bufio] dm_block_manager_create+0x5e/0x90 [dm_persistent_data] __create_persistent_data_objects+0x38/0x940 [dm_thin_pool] dm_pool_abort_metadata+0x64/0x90 [dm_thin_pool] metadata_operation_failed+0x59/0x100 [dm_thin_pool] alloc_data_block.isra.53+0x86/0x180 [dm_thin_pool] process_cell+0x2a3/0x550 [dm_thin_pool] do_worker+0x28d/0x8f0 [dm_thin_pool] process_one_work+0x171/0x370 worker_thread+0x49/0x3f0 kthread+0xf8/0x130 ret_from_fork+0x35/0x40 kobject_add_internal failed for :a-0000144 with -EEXIST, don't try to register things with the same name in the same directory. kmem_cache_create(dm_bufio_buffer-16) failed with error -17 Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1806151817130.6333@file01.intranet.prod.int.rdu2.redhat.com Signed-off-by: Mikulas Patocka Reported-by: Mike Snitzer Tested-by: Mike Snitzer Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/slub_def.h | 4 ++++ mm/slab_common.c | 4 ++++ mm/slub.c | 7 ++++++- 3 files changed, 14 insertions(+), 1 deletion(-) diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index 09fa2c6f0e68..3a1a1dbc6f49 100644 --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -155,8 +155,12 @@ struct kmem_cache { #ifdef CONFIG_SYSFS #define SLAB_SUPPORTS_SYSFS +void sysfs_slab_unlink(struct kmem_cache *); void sysfs_slab_release(struct kmem_cache *); #else +static inline void sysfs_slab_unlink(struct kmem_cache *s) +{ +} static inline void sysfs_slab_release(struct kmem_cache *s) { } diff --git a/mm/slab_common.c b/mm/slab_common.c index 890b1f04a03a..2296caf87bfb 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -567,10 +567,14 @@ static int shutdown_cache(struct kmem_cache *s) list_del(&s->list); if (s->flags & SLAB_TYPESAFE_BY_RCU) { +#ifdef SLAB_SUPPORTS_SYSFS + sysfs_slab_unlink(s); +#endif list_add_tail(&s->list, &slab_caches_to_rcu_destroy); schedule_work(&slab_caches_to_rcu_destroy_work); } else { #ifdef SLAB_SUPPORTS_SYSFS + sysfs_slab_unlink(s); sysfs_slab_release(s); #else slab_kmem_cache_release(s); diff --git a/mm/slub.c b/mm/slub.c index a3b8467c14af..51258eff4178 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5667,7 +5667,6 @@ static void sysfs_slab_remove_workfn(struct work_struct *work) kset_unregister(s->memcg_kset); #endif kobject_uevent(&s->kobj, KOBJ_REMOVE); - kobject_del(&s->kobj); out: kobject_put(&s->kobj); } @@ -5752,6 +5751,12 @@ static void sysfs_slab_remove(struct kmem_cache *s) schedule_work(&s->kobj_remove_work); } +void sysfs_slab_unlink(struct kmem_cache *s) +{ + if (slab_state >= FULL) + kobject_del(&s->kobj); +} + void sysfs_slab_release(struct kmem_cache *s) { if (slab_state >= FULL) From 124049decbb121ec32742c94fb5d9d6bed8f24d8 Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Wed, 27 Jun 2018 23:26:13 -0700 Subject: [PATCH 4/7] x86/e820: put !E820_TYPE_RAM regions into memblock.reserved There is a kernel panic that is triggered when reading /proc/kpageflags on the kernel booted with kernel parameter 'memmap=nn[KMG]!ss[KMG]': BUG: unable to handle kernel paging request at fffffffffffffffe PGD 9b20e067 P4D 9b20e067 PUD 9b210067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 2 PID: 1728 Comm: page-types Not tainted 4.17.0-rc6-mm1-v4.17-rc6-180605-0816-00236-g2dfb086ef02c+ #160 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.fc28 04/01/2014 RIP: 0010:stable_page_flags+0x27/0x3c0 Code: 00 00 00 0f 1f 44 00 00 48 85 ff 0f 84 a0 03 00 00 41 54 55 49 89 fc 53 48 8b 57 08 48 8b 2f 48 8d 42 ff 83 e2 01 48 0f 44 c7 <48> 8b 00 f6 c4 01 0f 84 10 03 00 00 31 db 49 8b 54 24 08 4c 89 e7 RSP: 0018:ffffbbd44111fde0 EFLAGS: 00010202 RAX: fffffffffffffffe RBX: 00007fffffffeff9 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000202 RDI: ffffed1182fff5c0 RBP: ffffffffffffffff R08: 0000000000000001 R09: 0000000000000001 R10: ffffbbd44111fed8 R11: 0000000000000000 R12: ffffed1182fff5c0 R13: 00000000000bffd7 R14: 0000000002fff5c0 R15: ffffbbd44111ff10 FS: 00007efc4335a500(0000) GS:ffff93a5bfc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffffffffffffe CR3: 00000000b2a58000 CR4: 00000000001406e0 Call Trace: kpageflags_read+0xc7/0x120 proc_reg_read+0x3c/0x60 __vfs_read+0x36/0x170 vfs_read+0x89/0x130 ksys_pread64+0x71/0x90 do_syscall_64+0x5b/0x160 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7efc42e75e23 Code: 09 00 ba 9f 01 00 00 e8 ab 81 f4 ff 66 2e 0f 1f 84 00 00 00 00 00 90 83 3d 29 0a 2d 00 00 75 13 49 89 ca b8 11 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 db d3 01 00 48 89 04 24 According to kernel bisection, this problem became visible due to commit f7f99100d8d9 ("mm: stop zeroing memory during allocation in vmemmap") which changes how struct pages are initialized. Memblock layout affects the pfn ranges covered by node/zone. Consider that we have a VM with 2 NUMA nodes and each node has 4GB memory, and the default (no memmap= given) memblock layout is like below: MEMBLOCK configuration: memory size = 0x00000001fff75c00 reserved size = 0x000000000300c000 memory.cnt = 0x4 memory[0x0] [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x0 memory[0x1] [0x0000000000100000-0x00000000bffd6fff], 0x00000000bfed7000 bytes on node 0 flags: 0x0 memory[0x2] [0x0000000100000000-0x000000013fffffff], 0x0000000040000000 bytes on node 0 flags: 0x0 memory[0x3] [0x0000000140000000-0x000000023fffffff], 0x0000000100000000 bytes on node 1 flags: 0x0 ... If you give memmap=1G!4G (so it just covers memory[0x2]), the range [0x100000000-0x13fffffff] is gone: MEMBLOCK configuration: memory size = 0x00000001bff75c00 reserved size = 0x000000000300c000 memory.cnt = 0x3 memory[0x0] [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x0 memory[0x1] [0x0000000000100000-0x00000000bffd6fff], 0x00000000bfed7000 bytes on node 0 flags: 0x0 memory[0x2] [0x0000000140000000-0x000000023fffffff], 0x0000000100000000 bytes on node 1 flags: 0x0 ... This causes shrinking node 0's pfn range because it is calculated by the address range of memblock.memory. So some of struct pages in the gap range are left uninitialized. We have a function zero_resv_unavail() which does zeroing the struct pages within the reserved unavailable range (i.e. memblock.memory && !memblock.reserved). This patch utilizes it to cover all unavailable ranges by putting them into memblock.reserved. Link: http://lkml.kernel.org/r/20180615072947.GB23273@hori1.linux.bs1.fc.nec.co.jp Fixes: f7f99100d8d9 ("mm: stop zeroing memory during allocation in vmemmap") Signed-off-by: Naoya Horiguchi Tested-by: Oscar Salvador Tested-by: "Herton R. Krzesinski" Acked-by: Michal Hocko Reviewed-by: Pavel Tatashin Cc: Steven Sistare Cc: Daniel Jordan Cc: Matthew Wilcox Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/kernel/e820.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index d1f25c831447..c88c23c658c1 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -1248,6 +1248,7 @@ void __init e820__memblock_setup(void) { int i; u64 end; + u64 addr = 0; /* * The bootstrap memblock region count maximum is 128 entries @@ -1264,13 +1265,21 @@ void __init e820__memblock_setup(void) struct e820_entry *entry = &e820_table->entries[i]; end = entry->addr + entry->size; + if (addr < entry->addr) + memblock_reserve(addr, entry->addr - addr); + addr = end; if (end != (resource_size_t)end) continue; + /* + * all !E820_TYPE_RAM ranges (including gap ranges) are put + * into memblock.reserved to make sure that struct pages in + * such regions are not left uninitialized after bootup. + */ if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN) - continue; - - memblock_add(entry->addr, entry->size); + memblock_reserve(entry->addr, entry->size); + else + memblock_add(entry->addr, entry->size); } /* Throw away partial pages: */ From f77bc3a82ce58fe7977a11f28e0b6cac8a9e087c Mon Sep 17 00:00:00 2001 From: Souptick Joarder Date: Wed, 27 Jun 2018 23:26:17 -0700 Subject: [PATCH 5/7] include/linux/dax.h: dax_iomap_fault() returns vm_fault_t Commit 1c8f422059ae ("mm: change return type to vm_fault_t") missed a conversion. It's not a big problem at present because mainline is still using typedef int vm_fault_t; Fixes: 1c8f422059ae ("mm: change return type to vm_fault_t") Link: http://lkml.kernel.org/r/20180620172046.GA27894@jordon-HP-15-Notebook-PC Signed-off-by: Souptick Joarder Reviewed-by: Andrew Morton Cc: Matthew Wilcox Cc: Dan Williams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/dax.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/dax.h b/include/linux/dax.h index 3855e3800f48..deb0f663252f 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -135,7 +135,7 @@ void dax_flush(struct dax_device *dax_dev, void *addr, size_t size); ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, const struct iomap_ops *ops); -int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, +vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, pfn_t *pfnp, int *errp, const struct iomap_ops *ops); vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, enum page_entry_size pe_size, pfn_t pfn); From dd275caf4a0d9b219fffe49288b6cc33cd564312 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Wed, 27 Jun 2018 23:26:20 -0700 Subject: [PATCH 6/7] kasan: depend on CONFIG_SLUB_DEBUG KASAN depends on having access to some of the accounting that SLUB_DEBUG does; without it, there are immediate crashes [1]. So, the natural thing to do is to make KASAN select SLUB_DEBUG. [1] http://lkml.kernel.org/r/CAHmME9rtoPwxUSnktxzKso14iuVCWT7BE_-_8PAC=pGw1iJnQg@mail.gmail.com Link: http://lkml.kernel.org/r/20180622154623.25388-1-Jason@zx2c4.com Fixes: f9e13c0a5a33 ("slab, slub: skip unnecessary kasan_cache_shutdown()") Signed-off-by: Jason A. Donenfeld Acked-by: Michal Hocko Reviewed-by: Shakeel Butt Acked-by: Christoph Lameter Cc: Shakeel Butt Cc: David Rientjes Cc: Pekka Enberg Cc: Joonsoo Kim Cc: Andrey Ryabinin Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/Kconfig.kasan | 1 + 1 file changed, 1 insertion(+) diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan index 3d35d062970d..c253c1b46c6b 100644 --- a/lib/Kconfig.kasan +++ b/lib/Kconfig.kasan @@ -6,6 +6,7 @@ if HAVE_ARCH_KASAN config KASAN bool "KASan: runtime memory debugger" depends on SLUB || (SLAB && !DEBUG_SLAB) + select SLUB_DEBUG if SLUB select CONSTRUCTORS select STACKDEPOT help From 008e682b5bf1bdd735b2eecf2f3903d7da49dd52 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Wed, 27 Jun 2018 23:26:24 -0700 Subject: [PATCH 7/7] proc: add Alexey to MAINTAINERS I know I'll regret it. Link: http://lkml.kernel.org/r/20180627194840.GA18113@avx2 Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- MAINTAINERS | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index bfb8a18d4793..07d1576fc766 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -11481,6 +11481,15 @@ W: http://wireless.kernel.org/en/users/Drivers/p54 S: Obsolete F: drivers/net/wireless/intersil/prism54/ +PROC FILESYSTEM +R: Alexey Dobriyan +L: linux-kernel@vger.kernel.org +L: linux-fsdevel@vger.kernel.org +S: Maintained +F: fs/proc/ +F: include/linux/proc_fs.h +F: tools/testing/selftests/proc/ + PROC SYSCTL M: "Luis R. Rodriguez" M: Kees Cook