mirror of https://gitee.com/openkylin/linux.git
15814 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Daniel Vetter
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2301002769 |
mutex: Add w/w mutex slowpath debugging
Injects EDEADLK conditions at pseudo-random interval, with exponential backoff up to UINT_MAX (to ensure that every lock operation still completes in a reasonable time). This way we can test the wound slowpath even for ww mutex users where contention is never expected, and the ww deadlock avoidance algorithm is only needed for correctness against malicious userspace. An example would be protecting kernel modesetting properties, which thanks to single-threaded X isn't really expected to contend, ever. I've looked into using the CONFIG_FAULT_INJECTION infrastructure, but decided against it for two reasons: - EDEADLK handling is mandatory for ww mutex users and should never affect the outcome of a syscall. This is in contrast to -ENOMEM injection. So fine configurability isn't required. - The fault injection framework only allows to set a simple probability for failure. Now the probability that a ww mutex acquire stage with N locks will never complete (due to too many injected EDEADLK backoffs) is zero. But the expected number of ww_mutex_lock operations for the completely uncontended case would be O(exp(N)). The per-acuiqire ctx exponential backoff solution choosen here only results in O(log N) overhead due to injection and so O(log N * N) lock operations. This way we can fail with high probability (and so have good test coverage even for fancy backoff and lock acquisition paths) without running into patalogical cases. Note that EDEADLK will only ever be injected when we managed to acquire the lock. This prevents any behaviour changes for users which rely on the EALREADY semantics. Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Cc: rostedt@goodmis.org Cc: daniel@ffwll.ch Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20130620113117.4001.21681.stgit@patser Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Maarten Lankhorst
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040a0a3710 |
mutex: Add support for wound/wait style locks
Wound/wait mutexes are used when other multiple lock acquisitions of a similar type can be done in an arbitrary order. The deadlock handling used here is called wait/wound in the RDBMS literature: The older tasks waits until it can acquire the contended lock. The younger tasks needs to back off and drop all the locks it is currently holding, i.e. the younger task is wounded. For full documentation please read Documentation/ww-mutex-design.txt. References: https://lwn.net/Articles/548909/ Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Rob Clark <robdclark@gmail.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Cc: rostedt@goodmis.org Cc: daniel@ffwll.ch Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/51C8038C.9000106@canonical.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Maarten Lankhorst
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a41b56efa7 |
arch: Make __mutex_fastpath_lock_retval return whether fastpath succeeded or not
This will allow me to call functions that have multiple arguments if fastpath fails. This is required to support ticket mutexes, because they need to be able to pass an extra argument to the fail function. Originally I duplicated the functions, by adding __mutex_fastpath_lock_retval_arg. This ended up being just a duplication of the existing function, so a way to test if fastpath was called ended up being better. This also cleaned up the reservation mutex patch some by being able to call an atomic_set instead of atomic_xchg, and making it easier to detect if the wrong unlock function was previously used. Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Cc: robclark@gmail.com Cc: rostedt@goodmis.org Cc: daniel@ffwll.ch Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20130620113105.4001.83929.stgit@patser Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Linus Torvalds
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f71194a7d4 |
Merge branch 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Peter Anvin: "This series fixes a couple of build failures, and fixes MTRR cleanup and memory setup on very specific memory maps. Finally, it fixes triggering backtraces on all CPUs, which was inadvertently disabled on x86." * 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/efi: Fix dummy variable buffer allocation x86: Fix trigger_all_cpu_backtrace() implementation x86: Fix section mismatch on load_ucode_ap x86: fix build error and kconfig for ia32_emulation and binfmt range: Do not add new blank slot with add_range_with_merge x86, mtrr: Fix original mtrr range get for mtrr_cleanup |
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Linus Torvalds
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a3d5c3460a |
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar: "Two smaller fixes - plus a context tracking tracing fix that is a bit bigger" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tracing/context-tracking: Add preempt_schedule_context() for tracing sched: Fix clear NOHZ_BALANCE_KICK sched/x86: Construct all sibling maps if smt |
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Linus Torvalds
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86c76676cf |
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar: "Four fixes. The mmap ones are unfortunately larger than desired - fuzzing uncovered bugs that needed perf context life time management changes to fix properly" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86: Fix broken PEBS-LL support on SNB-EP/IVB-EP perf: Fix mmap() accounting hole perf: Fix perf mmap bugs kprobes: Fix to free gone and unused optprobes |
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Linus Torvalds
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805e318548 |
Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull cpu idle fixes from Thomas Gleixner: - Add a missing irq enable. Fallout of the idle conversion - Fix stackprotector wreckage caused by the idle conversion * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: idle: Enable interrupts in the weak arch_cpu_idle() implementation idle: Add the stack canary init to cpu_startup_entry() |
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Linus Torvalds
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4db88eb4c3 |
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Thomas Gleixner: - Fix inconstinant clock usage in virtual time accounting - Fix a build error in KVM caused by the NOHZ work - Remove a pointless timekeeping duty assignment which breaks NOHZ - Use a proper notifier return value to avoid random behaviour * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tick: Remove useless timekeeping duty attribution to broadcast source nohz: Fix notifier return val that enforce timekeeping kvm: Move guest entry/exit APIs to context_tracking vtime: Use consistent clocks among nohz accounting |
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Steven Rostedt
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29bb9e5a75 |
tracing/context-tracking: Add preempt_schedule_context() for tracing
Dave Jones hit the following bug report: =============================== [ INFO: suspicious RCU usage. ] 3.10.0-rc2+ #1 Not tainted ------------------------------- include/linux/rcupdate.h:771 rcu_read_lock() used illegally while idle! other info that might help us debug this: RCU used illegally from idle CPU! rcu_scheduler_active = 1, debug_locks = 0 RCU used illegally from extended quiescent state! 2 locks held by cc1/63645: #0: (&rq->lock){-.-.-.}, at: [<ffffffff816b39fd>] __schedule+0xed/0x9b0 #1: (rcu_read_lock){.+.+..}, at: [<ffffffff8109d645>] cpuacct_charge+0x5/0x1f0 CPU: 1 PID: 63645 Comm: cc1 Not tainted 3.10.0-rc2+ #1 [loadavg: 40.57 27.55 13.39 25/277 64369] Hardware name: Gigabyte Technology Co., Ltd. GA-MA78GM-S2H/GA-MA78GM-S2H, BIOS F12a 04/23/2010 0000000000000000 ffff88010f78fcf8 ffffffff816ae383 ffff88010f78fd28 ffffffff810b698d ffff88011c092548 000000000023d073 ffff88011c092500 0000000000000001 ffff88010f78fd60 ffffffff8109d7c5 ffffffff8109d645 Call Trace: [<ffffffff816ae383>] dump_stack+0x19/0x1b [<ffffffff810b698d>] lockdep_rcu_suspicious+0xfd/0x130 [<ffffffff8109d7c5>] cpuacct_charge+0x185/0x1f0 [<ffffffff8109d645>] ? cpuacct_charge+0x5/0x1f0 [<ffffffff8108dffc>] update_curr+0xec/0x240 [<ffffffff8108f528>] put_prev_task_fair+0x228/0x480 [<ffffffff816b3a71>] __schedule+0x161/0x9b0 [<ffffffff816b4721>] preempt_schedule+0x51/0x80 [<ffffffff816b4800>] ? __cond_resched_softirq+0x60/0x60 [<ffffffff816b6824>] ? retint_careful+0x12/0x2e [<ffffffff810ff3cc>] ftrace_ops_control_func+0x1dc/0x210 [<ffffffff816be280>] ftrace_call+0x5/0x2f [<ffffffff816b681d>] ? retint_careful+0xb/0x2e [<ffffffff816b4805>] ? schedule_user+0x5/0x70 [<ffffffff816b4805>] ? schedule_user+0x5/0x70 [<ffffffff816b6824>] ? retint_careful+0x12/0x2e ------------[ cut here ]------------ What happened was that the function tracer traced the schedule_user() code that tells RCU that the system is coming back from userspace, and to add the CPU back to the RCU monitoring. Because the function tracer does a preempt_disable/enable_notrace() calls the preempt_enable_notrace() checks the NEED_RESCHED flag. If it is set, then preempt_schedule() is called. But this is called before the user_exit() function can inform the kernel that the CPU is no longer in user mode and needs to be accounted for by RCU. The fix is to create a new preempt_schedule_context() that checks if the kernel is still in user mode and if so to switch it to kernel mode before calling schedule. It also switches back to user mode coming back from schedule in need be. The only user of this currently is the preempt_enable_notrace(), which is only used by the tracing subsystem. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1369423420.6828.226.camel@gandalf.local.home Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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873b4c65b5 |
sched: Fix clear NOHZ_BALANCE_KICK
I have faced a sequence where the Idle Load Balance was sometime not
triggered for a while on my platform, in the following scenario:
CPU 0 and CPU 1 are running tasks and CPU 2 is idle
CPU 1 kicks the Idle Load Balance
CPU 1 selects CPU 2 as the new Idle Load Balancer
CPU 2 sets NOHZ_BALANCE_KICK for CPU 2
CPU 2 sends a reschedule IPI to CPU 2
While CPU 3 wakes up, CPU 0 or CPU 1 migrates a waking up task A on CPU 2
CPU 2 finally wakes up, runs task A and discards the Idle Load Balance
task A quickly goes back to sleep (before a tick occurs on CPU 2)
CPU 2 goes back to idle with NOHZ_BALANCE_KICK set
Whenever CPU 2 will be selected as the ILB, no reschedule IPI will be sent
because NOHZ_BALANCE_KICK is already set and no Idle Load Balance will be
performed.
We must wait for the sched softirq to be raised on CPU 2 thanks to another
part the kernel to come back to clear NOHZ_BALANCE_KICK.
The proposed solution clears NOHZ_BALANCE_KICK in schedule_ipi if
we can't raise the sched_softirq for the Idle Load Balance.
Change since V1:
- move the clear of NOHZ_BALANCE_KICK in got_nohz_idle_kick if the ILB
can't run on this CPU (as suggested by Peter)
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1370419991-13870-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Peter Zijlstra
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9bb5d40cd9 |
perf: Fix mmap() accounting hole
Vince's fuzzer once again found holes. This time it spotted a leak in the locked page accounting. When an event had redirected output and its close() was the last reference to the buffer we didn't have a vm context to undo accounting. Change the code to destroy the buffer on the last munmap() and detach all redirected events at that time. This provides us the right context to undo the vm accounting. Reported-and-tested-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20130604084421.GI8923@twins.programming.kicks-ass.net Cc: <stable@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Yinghai Lu
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0541881502 |
range: Do not add new blank slot with add_range_with_merge
Joshua reported: Commit cd7b304dfaf1 (x86, range: fix missing merge
during add range) broke mtrr cleanup on his setup in 3.9.5.
corresponding commit in upstream is
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Linus Torvalds
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d0ff934881 |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull VFS fixes from Al Viro: "Several fixes + obvious cleanup (you've missed a couple of open-coded can_lookup() back then)" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: snd_pcm_link(): fix a leak... use can_lookup() instead of direct checks of ->i_op->lookup move exit_task_namespaces() outside of exit_notify() fput: task_work_add() can fail if the caller has passed exit_task_work() ncpfs: fix rmdir returns Device or resource busy |
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Oleg Nesterov
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8aac62706a |
move exit_task_namespaces() outside of exit_notify()
exit_notify() does exit_task_namespaces() after
forget_original_parent(). This was needed to ensure that ->nsproxy
can't be cleared prematurely, an exiting child we are going to
reparent can do do_notify_parent() and use the parent's (ours) pid_ns.
However, after
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James Bottomley
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29ce3785b2 |
idle: Enable interrupts in the weak arch_cpu_idle() implementation
PARISC bootup triggers the warning at kernel/cpu/idle.c:96. That's caused by the weak arch_cpu_idle() implementation, which is provided to avoid that architectures implement idle_poll over and over. The switchover to polling mode happens in the first call of the weak arch_cpu_idle() implementation, but that code fails to reenable interrupts and therefor triggers the warning. Fix this by enabling interrupts in the weak arch_cpu_idle() code. [ tglx: Made the changelog match the patch ] Signed-off-by: James Bottomley <JBottomley@Parallels.com> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1371236142.2726.43.camel@dabdike Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
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Linus Torvalds
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cb7e9704d5 |
Merge branch 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu
Pull RCU fixes from Paul McKenney:
"I must confess that this past merge window was not RCU's best showing.
This series contains three more fixes for RCU regressions:
1. A fix to __DECLARE_TRACE_RCU() that causes it to act as an
interrupt from idle rather than as a task switch from idle.
This change is needed due to the recent use of _rcuidle()
tracepoints that can be invoked from interrupt handlers as well
as from idle. Without this fix, invoking _rcuidle() tracepoints
from interrupt handlers results in splats and (more seriously)
confusion on RCU's part as to whether a given CPU is idle or not.
This confusion can in turn result in too-short grace periods and
therefore random memory corruption.
2. A fix to a subtle deadlock that could result due to RCU doing
a wakeup while holding one of its rcu_node structure's locks.
Although the probability of occurrence is low, it really
does happen. The fix, courtesy of Steven Rostedt, uses
irq_work_queue() to avoid the deadlock.
3. A fix to a silent deadlock (invisible to lockdep) due to the
interaction of timeouts posted by RCU debug code enabled by
CONFIG_PROVE_RCU_DELAY=y, grace-period initialization, and CPU
hotplug operations. This will not occur in production kernels,
but really does occur in randconfig testing. Diagnosis courtesy
of Steven Rostedt"
* 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
rcu: Fix deadlock with CPU hotplug, RCU GP init, and timer migration
rcu: Don't call wakeup() with rcu_node structure ->lock held
trace: Allow idle-safe tracepoints to be called from irq
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Linus Torvalds
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a568fa1c91 |
Merge branch 'akpm' (updates from Andrew Morton)
Merge misc fixes from Andrew Morton: "Bunch of fixes and one little addition to math64.h" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (27 commits) include/linux/math64.h: add div64_ul() mm: memcontrol: fix lockless reclaim hierarchy iterator frontswap: fix incorrect zeroing and allocation size for frontswap_map kernel/audit_tree.c:audit_add_tree_rule(): protect `rule' from kill_rules() mm: migration: add migrate_entry_wait_huge() ocfs2: add missing lockres put in dlm_mig_lockres_handler mm/page_alloc.c: fix watermark check in __zone_watermark_ok() drivers/misc/sgi-gru/grufile.c: fix info leak in gru_get_config_info() aio: fix io_destroy() regression by using call_rcu() rtc-at91rm9200: use shadow IMR on at91sam9x5 rtc-at91rm9200: add shadow interrupt mask rtc-at91rm9200: refactor interrupt-register handling rtc-at91rm9200: add configuration support rtc-at91rm9200: add match-table compile guard fs/ocfs2/namei.c: remove unecessary ERROR when removing non-empty directory swap: avoid read_swap_cache_async() race to deadlock while waiting on discard I/O completion drivers/rtc/rtc-twl.c: fix missing device_init_wakeup() when booted with device tree cciss: fix broken mutex usage in ioctl audit: wait_for_auditd() should use TASK_UNINTERRUPTIBLE drivers/rtc/rtc-cmos.c: fix accidentally enabling rtc channel ... |
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Chen Gang
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736f3203a0 |
kernel/audit_tree.c:audit_add_tree_rule(): protect `rule' from kill_rules()
audit_add_tree_rule() must set 'rule->tree = NULL;' firstly, to protect
the rule itself freed in kill_rules().
The reason is when it is killed, the 'rule' itself may have already
released, we should not access it. one example: we add a rule to an
inode, just at the same time the other task is deleting this inode.
The work flow for adding a rule:
audit_receive() -> (need audit_cmd_mutex lock)
audit_receive_skb() ->
audit_receive_msg() ->
audit_receive_filter() ->
audit_add_rule() ->
audit_add_tree_rule() -> (need audit_filter_mutex lock)
...
unlock audit_filter_mutex
get_tree()
...
iterate_mounts() -> (iterate all related inodes)
tag_mount() ->
tag_trunk() ->
create_trunk() -> (assume it is 1st rule)
fsnotify_add_mark() ->
fsnotify_add_inode_mark() -> (add mark to inode->i_fsnotify_marks)
...
get_tree(); (each inode will get one)
...
lock audit_filter_mutex
The work flow for deleting an inode:
__destroy_inode() ->
fsnotify_inode_delete() ->
__fsnotify_inode_delete() ->
fsnotify_clear_marks_by_inode() -> (get mark from inode->i_fsnotify_marks)
fsnotify_destroy_mark() ->
fsnotify_destroy_mark_locked() ->
audit_tree_freeing_mark() ->
evict_chunk() ->
...
tree->goner = 1
...
kill_rules() -> (assume current->audit_context == NULL)
call_rcu() -> (rule->tree != NULL)
audit_free_rule_rcu() ->
audit_free_rule()
...
audit_schedule_prune() -> (assume current->audit_context == NULL)
kthread_run() -> (need audit_cmd_mutex and audit_filter_mutex lock)
prune_one() -> (delete it from prue_list)
put_tree(); (match the original get_tree above)
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Oleg Nesterov
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f000cfdde5 |
audit: wait_for_auditd() should use TASK_UNINTERRUPTIBLE
audit_log_start() does wait_for_auditd() in a loop until audit_backlog_wait_time passes or audit_skb_queue has a room. If signal_pending() is true this becomes a busy-wait loop, schedule() in TASK_INTERRUPTIBLE won't block. Thanks to Guy for fully investigating and explaining the problem. (akpm: that'll cause the system to lock up on a non-preemptible uniprocessor kernel) (Guy: "Our customer was in fact running a uniprocessor machine, and they reported a system hang.") Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reported-by: Guy Streeter <streeter@redhat.com> Cc: Eric Paris <eparis@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kees Cook
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637241a900 |
kmsg: honor dmesg_restrict sysctl on /dev/kmsg
The dmesg_restrict sysctl currently covers the syslog method for access
dmesg, however /dev/kmsg isn't covered by the same protections. Most
people haven't noticed because util-linux dmesg(1) defaults to using the
syslog method for access in older versions. With util-linux dmesg(1)
defaults to reading directly from /dev/kmsg.
To fix /dev/kmsg, let's compare the existing interfaces and what they
allow:
- /proc/kmsg allows:
- open (SYSLOG_ACTION_OPEN) if CAP_SYSLOG since it uses a destructive
single-reader interface (SYSLOG_ACTION_READ).
- everything, after an open.
- syslog syscall allows:
- anything, if CAP_SYSLOG.
- SYSLOG_ACTION_READ_ALL and SYSLOG_ACTION_SIZE_BUFFER, if
dmesg_restrict==0.
- nothing else (EPERM).
The use-cases were:
- dmesg(1) needs to do non-destructive SYSLOG_ACTION_READ_ALLs.
- sysklog(1) needs to open /proc/kmsg, drop privs, and still issue the
destructive SYSLOG_ACTION_READs.
AIUI, dmesg(1) is moving to /dev/kmsg, and systemd-journald doesn't
clear the ring buffer.
Based on the comments in devkmsg_llseek, it sounds like actions besides
reading aren't going to be supported by /dev/kmsg (i.e.
SYSLOG_ACTION_CLEAR), so we have a strict subset of the non-destructive
syslog syscall actions.
To this end, move the check as Josh had done, but also rename the
constants to reflect their new uses (SYSLOG_FROM_CALL becomes
SYSLOG_FROM_READER, and SYSLOG_FROM_FILE becomes SYSLOG_FROM_PROC).
SYSLOG_FROM_READER allows non-destructive actions, and SYSLOG_FROM_PROC
allows destructive actions after a capabilities-constrained
SYSLOG_ACTION_OPEN check.
- /dev/kmsg allows:
- open if CAP_SYSLOG or dmesg_restrict==0
- reading/polling, after open
Addresses https://bugzilla.redhat.com/show_bug.cgi?id=903192
[akpm@linux-foundation.org: use pr_warn_once()]
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Christian Kujau <lists@nerdbynature.de>
Tested-by: Josh Boyer <jwboyer@redhat.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Robin Holt
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cf7df378aa |
reboot: rigrate shutdown/reboot to boot cpu
We recently noticed that reboot of a 1024 cpu machine takes approx 16
minutes of just stopping the cpus. The slowdown was tracked to commit
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Srivatsa S. Bhat
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16e53dbf10 |
CPU hotplug: provide a generic helper to disable/enable CPU hotplug
There are instances in the kernel where we would like to disable CPU hotplug (from sysfs) during some important operation. Today the freezer code depends on this and the code to do it was kinda tailor-made for that. Restructure the code and make it generic enough to be useful for other usecases too. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Robin Holt <holt@sgi.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Russ Anderson <rja@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Shawn Guo <shawn.guo@linaro.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Linus Torvalds
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45d53766b9 |
Yoshihiro Yunomae fixed a regression in the output format when using
one of the counter clocks. The new multibuffer code changed the trace_clock file to update the trace instances tr->clock_id but the actual traces still used the value from the obsolete global variable trace_clock_id. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQEcBAABAgAGBQJRt8hEAAoJEOdOSU1xswtM6+EH/jAEuOrXhkkDqcua/paAOngw XWSaF9Cr6ozh4hutFrVSBi3AnsDrVo0adZmMVvLS9a7goyIUdYLfXbNeyK6Nvcq5 bGXR5sJNpjtQ7snrmGX2KlXIGix28adi49eACi4qsGSG/jJYORYlgXcNBeXtENsb PKTXdQ8XEyc/h7Q51YQPHIVunf+zJSoepuXZ0myPLUWzLlPX9qoy5kETEpGhh9xh Ianb4wLo8dn6JuVGBuXQhZ/VzUHwJT1jJxR2JfnZ0bNVplNilnumAxY8f2zPOmzT lvIiQjCMRvNExFShuFh9WNnGRi62zYE9e0JJpYL4W9moIcbbEUvXYt2/imAVe9Q= =H+Wb -----END PGP SIGNATURE----- Merge tag 'trace-fixes-v3.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fix from Steven Rostedt: "Yoshihiro Yunomae fixed a regression in the output format when using one of the counter clocks. The new multibuffer code changed the trace_clock file to update the trace instances tr->clock_id but the actual traces still used the value from the obsolete global variable trace_clock_id" * tag 'trace-fixes-v3.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Fix outputting formats of x86-tsc and counter when use trace_clock |
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Thomas Gleixner
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d7880812b3 |
idle: Add the stack canary init to cpu_startup_entry()
Moving x86 to the generic idle implementation (commit
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Yoshihiro YUNOMAE
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58e8eedf18 |
tracing: Fix outputting formats of x86-tsc and counter when use trace_clock
Outputting formats of x86-tsc and counter should be a raw format, but after
applying the patch(
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Ben Greear
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34376a50fb |
Fix lockup related to stop_machine being stuck in __do_softirq.
The stop machine logic can lock up if all but one of the migration
threads make it through the disable-irq step and the one remaining
thread gets stuck in __do_softirq. The reason __do_softirq can hang is
that it has a bail-out based on jiffies timeout, but in the lockup case,
jiffies itself is not incremented.
To work around this, re-add the max_restart counter in __do_irq and stop
processing irqs after 10 restarts.
Thanks to Tejun Heo and Rusty Russell and others for helping me track
this down.
This was introduced in 3.9 by commit
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Paul E. McKenney
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971394f389 |
rcu: Fix deadlock with CPU hotplug, RCU GP init, and timer migration
In Steven Rostedt's words: > I've been debugging the last couple of days why my tests have been > locking up. One of my tracing tests, runs all available tracers. The > lockup always happened with the mmiotrace, which is used to trace > interactions between priority drivers and the kernel. But to do this > easily, when the tracer gets registered, it disables all but the boot > CPUs. The lockup always happened after it got done disabling the CPUs. > > Then I decided to try this: > > while :; do > for i in 1 2 3; do > echo 0 > /sys/devices/system/cpu/cpu$i/online > done > for i in 1 2 3; do > echo 1 > /sys/devices/system/cpu/cpu$i/online > done > done > > Well, sure enough, that locked up too, with the same users. Doing a > sysrq-w (showing all blocked tasks): > > [ 2991.344562] task PC stack pid father > [ 2991.344562] rcu_preempt D ffff88007986fdf8 0 10 2 0x00000000 > [ 2991.344562] ffff88007986fc98 0000000000000002 ffff88007986fc48 0000000000000908 > [ 2991.344562] ffff88007986c280 ffff88007986ffd8 ffff88007986ffd8 00000000001d3c80 > [ 2991.344562] ffff880079248a40 ffff88007986c280 0000000000000000 00000000fffd4295 > [ 2991.344562] Call Trace: > [ 2991.344562] [<ffffffff815437ba>] schedule+0x64/0x66 > [ 2991.344562] [<ffffffff81541750>] schedule_timeout+0xbc/0xf9 > [ 2991.344562] [<ffffffff8154bec0>] ? ftrace_call+0x5/0x2f > [ 2991.344562] [<ffffffff81049513>] ? cascade+0xa8/0xa8 > [ 2991.344562] [<ffffffff815417ab>] schedule_timeout_uninterruptible+0x1e/0x20 > [ 2991.344562] [<ffffffff810c980c>] rcu_gp_kthread+0x502/0x94b > [ 2991.344562] [<ffffffff81062791>] ? __init_waitqueue_head+0x50/0x50 > [ 2991.344562] [<ffffffff810c930a>] ? rcu_gp_fqs+0x64/0x64 > [ 2991.344562] [<ffffffff81061cdb>] kthread+0xb1/0xb9 > [ 2991.344562] [<ffffffff81091e31>] ? lock_release_holdtime.part.23+0x4e/0x55 > [ 2991.344562] [<ffffffff81061c2a>] ? __init_kthread_worker+0x58/0x58 > [ 2991.344562] [<ffffffff8154c1dc>] ret_from_fork+0x7c/0xb0 > [ 2991.344562] [<ffffffff81061c2a>] ? __init_kthread_worker+0x58/0x58 > [ 2991.344562] kworker/0:1 D ffffffff81a30680 0 47 2 0x00000000 > [ 2991.344562] Workqueue: events cpuset_hotplug_workfn > [ 2991.344562] ffff880078dbbb58 0000000000000002 0000000000000006 00000000000000d8 > [ 2991.344562] ffff880078db8100 ffff880078dbbfd8 ffff880078dbbfd8 00000000001d3c80 > [ 2991.344562] ffff8800779ca5c0 ffff880078db8100 ffffffff81541fcf 0000000000000000 > [ 2991.344562] Call Trace: > [ 2991.344562] [<ffffffff81541fcf>] ? __mutex_lock_common+0x3d4/0x609 > [ 2991.344562] [<ffffffff815437ba>] schedule+0x64/0x66 > [ 2991.344562] [<ffffffff81543a39>] schedule_preempt_disabled+0x18/0x24 > [ 2991.344562] [<ffffffff81541fcf>] __mutex_lock_common+0x3d4/0x609 > [ 2991.344562] [<ffffffff8103d11b>] ? get_online_cpus+0x3c/0x50 > [ 2991.344562] [<ffffffff8103d11b>] ? get_online_cpus+0x3c/0x50 > [ 2991.344562] [<ffffffff815422ff>] mutex_lock_nested+0x3b/0x40 > [ 2991.344562] [<ffffffff8103d11b>] get_online_cpus+0x3c/0x50 > [ 2991.344562] [<ffffffff810af7e6>] rebuild_sched_domains_locked+0x6e/0x3a8 > [ 2991.344562] [<ffffffff810b0ec6>] rebuild_sched_domains+0x1c/0x2a > [ 2991.344562] [<ffffffff810b109b>] cpuset_hotplug_workfn+0x1c7/0x1d3 > [ 2991.344562] [<ffffffff810b0ed9>] ? cpuset_hotplug_workfn+0x5/0x1d3 > [ 2991.344562] [<ffffffff81058e07>] process_one_work+0x2d4/0x4d1 > [ 2991.344562] [<ffffffff81058d3a>] ? process_one_work+0x207/0x4d1 > [ 2991.344562] [<ffffffff8105964c>] worker_thread+0x2e7/0x3b5 > [ 2991.344562] [<ffffffff81059365>] ? rescuer_thread+0x332/0x332 > [ 2991.344562] [<ffffffff81061cdb>] kthread+0xb1/0xb9 > [ 2991.344562] [<ffffffff81061c2a>] ? __init_kthread_worker+0x58/0x58 > [ 2991.344562] [<ffffffff8154c1dc>] ret_from_fork+0x7c/0xb0 > [ 2991.344562] [<ffffffff81061c2a>] ? __init_kthread_worker+0x58/0x58 > [ 2991.344562] bash D ffffffff81a4aa80 0 2618 2612 0x10000000 > [ 2991.344562] ffff8800379abb58 0000000000000002 0000000000000006 0000000000000c2c > [ 2991.344562] ffff880077fea140 ffff8800379abfd8 ffff8800379abfd8 00000000001d3c80 > [ 2991.344562] ffff8800779ca5c0 ffff880077fea140 ffffffff81541fcf 0000000000000000 > [ 2991.344562] Call Trace: > [ 2991.344562] [<ffffffff81541fcf>] ? __mutex_lock_common+0x3d4/0x609 > [ 2991.344562] [<ffffffff815437ba>] schedule+0x64/0x66 > [ 2991.344562] [<ffffffff81543a39>] schedule_preempt_disabled+0x18/0x24 > [ 2991.344562] [<ffffffff81541fcf>] __mutex_lock_common+0x3d4/0x609 > [ 2991.344562] [<ffffffff81530078>] ? rcu_cpu_notify+0x2f5/0x86e > [ 2991.344562] [<ffffffff81530078>] ? rcu_cpu_notify+0x2f5/0x86e > [ 2991.344562] [<ffffffff815422ff>] mutex_lock_nested+0x3b/0x40 > [ 2991.344562] [<ffffffff81530078>] rcu_cpu_notify+0x2f5/0x86e > [ 2991.344562] [<ffffffff81091c99>] ? __lock_is_held+0x32/0x53 > [ 2991.344562] [<ffffffff81548912>] notifier_call_chain+0x6b/0x98 > [ 2991.344562] [<ffffffff810671fd>] __raw_notifier_call_chain+0xe/0x10 > [ 2991.344562] [<ffffffff8103cf64>] __cpu_notify+0x20/0x32 > [ 2991.344562] [<ffffffff8103cf8d>] cpu_notify_nofail+0x17/0x36 > [ 2991.344562] [<ffffffff815225de>] _cpu_down+0x154/0x259 > [ 2991.344562] [<ffffffff81522710>] cpu_down+0x2d/0x3a > [ 2991.344562] [<ffffffff81526351>] store_online+0x4e/0xe7 > [ 2991.344562] [<ffffffff8134d764>] dev_attr_store+0x20/0x22 > [ 2991.344562] [<ffffffff811b3c5f>] sysfs_write_file+0x108/0x144 > [ 2991.344562] [<ffffffff8114c5ef>] vfs_write+0xfd/0x158 > [ 2991.344562] [<ffffffff8114c928>] SyS_write+0x5c/0x83 > [ 2991.344562] [<ffffffff8154c494>] tracesys+0xdd/0xe2 > > As well as held locks: > > [ 3034.728033] Showing all locks held in the system: > [ 3034.728033] 1 lock held by rcu_preempt/10: > [ 3034.728033] #0: (rcu_preempt_state.onoff_mutex){+.+...}, at: [<ffffffff810c9471>] rcu_gp_kthread+0x167/0x94b > [ 3034.728033] 4 locks held by kworker/0:1/47: > [ 3034.728033] #0: (events){.+.+.+}, at: [<ffffffff81058d3a>] process_one_work+0x207/0x4d1 > [ 3034.728033] #1: (cpuset_hotplug_work){+.+.+.}, at: [<ffffffff81058d3a>] process_one_work+0x207/0x4d1 > [ 3034.728033] #2: (cpuset_mutex){+.+.+.}, at: [<ffffffff810b0ec1>] rebuild_sched_domains+0x17/0x2a > [ 3034.728033] #3: (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff8103d11b>] get_online_cpus+0x3c/0x50 > [ 3034.728033] 1 lock held by mingetty/2563: > [ 3034.728033] #0: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8131e28a>] n_tty_read+0x252/0x7e8 > [ 3034.728033] 1 lock held by mingetty/2565: > [ 3034.728033] #0: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8131e28a>] n_tty_read+0x252/0x7e8 > [ 3034.728033] 1 lock held by mingetty/2569: > [ 3034.728033] #0: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8131e28a>] n_tty_read+0x252/0x7e8 > [ 3034.728033] 1 lock held by mingetty/2572: > [ 3034.728033] #0: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8131e28a>] n_tty_read+0x252/0x7e8 > [ 3034.728033] 1 lock held by mingetty/2575: > [ 3034.728033] #0: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8131e28a>] n_tty_read+0x252/0x7e8 > [ 3034.728033] 7 locks held by bash/2618: > [ 3034.728033] #0: (sb_writers#5){.+.+.+}, at: [<ffffffff8114bc3f>] file_start_write+0x2a/0x2c > [ 3034.728033] #1: (&buffer->mutex#2){+.+.+.}, at: [<ffffffff811b3b93>] sysfs_write_file+0x3c/0x144 > [ 3034.728033] #2: (s_active#54){.+.+.+}, at: [<ffffffff811b3c3e>] sysfs_write_file+0xe7/0x144 > [ 3034.728033] #3: (x86_cpu_hotplug_driver_mutex){+.+.+.}, at: [<ffffffff810217c2>] cpu_hotplug_driver_lock+0x17/0x19 > [ 3034.728033] #4: (cpu_add_remove_lock){+.+.+.}, at: [<ffffffff8103d196>] cpu_maps_update_begin+0x17/0x19 > [ 3034.728033] #5: (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff8103cfd8>] cpu_hotplug_begin+0x2c/0x6d > [ 3034.728033] #6: (rcu_preempt_state.onoff_mutex){+.+...}, at: [<ffffffff81530078>] rcu_cpu_notify+0x2f5/0x86e > [ 3034.728033] 1 lock held by bash/2980: > [ 3034.728033] #0: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8131e28a>] n_tty_read+0x252/0x7e8 > > Things looked a little weird. Also, this is a deadlock that lockdep did > not catch. But what we have here does not look like a circular lock > issue: > > Bash is blocked in rcu_cpu_notify(): > > 1961 /* Exclude any attempts to start a new grace period. */ > 1962 mutex_lock(&rsp->onoff_mutex); > > > kworker is blocked in get_online_cpus(), which makes sense as we are > currently taking down a CPU. > > But rcu_preempt is not blocked on anything. It is simply sleeping in > rcu_gp_kthread (really rcu_gp_init) here: > > 1453 #ifdef CONFIG_PROVE_RCU_DELAY > 1454 if ((prandom_u32() % (rcu_num_nodes * 8)) == 0 && > 1455 system_state == SYSTEM_RUNNING) > 1456 schedule_timeout_uninterruptible(2); > 1457 #endif /* #ifdef CONFIG_PROVE_RCU_DELAY */ > > And it does this while holding the onoff_mutex that bash is waiting for. > > Doing a function trace, it showed me where it happened: > > [ 125.940066] rcu_pree-10 3.... 28384115273: schedule_timeout_uninterruptible <-rcu_gp_kthread > [...] > [ 125.940066] rcu_pree-10 3d..3 28384202439: sched_switch: prev_comm=rcu_preempt prev_pid=10 prev_prio=120 prev_state=D ==> next_comm=watchdog/3 next_pid=38 next_prio=120 > > The watchdog ran, and then: > > [ 125.940066] watchdog-38 3d..3 28384692863: sched_switch: prev_comm=watchdog/3 prev_pid=38 prev_prio=120 prev_state=P ==> next_comm=modprobe next_pid=2848 next_prio=118 > > Not sure what modprobe was doing, but shortly after that: > > [ 125.940066] modprobe-2848 3d..3 28385041749: sched_switch: prev_comm=modprobe prev_pid=2848 prev_prio=118 prev_state=R+ ==> next_comm=migration/3 next_pid=40 next_prio=0 > > Where the migration thread took down the CPU: > > [ 125.940066] migratio-40 3d..3 28389148276: sched_switch: prev_comm=migration/3 prev_pid=40 prev_prio=0 prev_state=P ==> next_comm=swapper/3 next_pid=0 next_prio=120 > > which finally did: > > [ 125.940066] <idle>-0 3...1 28389282142: arch_cpu_idle_dead <-cpu_startup_entry > [ 125.940066] <idle>-0 3...1 28389282548: native_play_dead <-arch_cpu_idle_dead > [ 125.940066] <idle>-0 3...1 28389282924: play_dead_common <-native_play_dead > [ 125.940066] <idle>-0 3...1 28389283468: idle_task_exit <-play_dead_common > [ 125.940066] <idle>-0 3...1 28389284644: amd_e400_remove_cpu <-play_dead_common > > > CPU 3 is now offline, the rcu_preempt thread that ran on CPU 3 is still > doing a schedule_timeout_uninterruptible() and it registered it's > timeout to the timer base for CPU 3. You would think that it would get > migrated right? The issue here is that the timer migration happens at > the CPU notifier for CPU_DEAD. The problem is that the rcu notifier for > CPU_DOWN is blocked waiting for the onoff_mutex to be released, which is > held by the thread that just put itself into a uninterruptible sleep, > that wont wake up until the CPU_DEAD notifier of the timer > infrastructure is called, which wont happen until the rcu notifier > finishes. Here's our deadlock! This commit breaks this deadlock cycle by substituting a shorter udelay() for the previous schedule_timeout_uninterruptible(), while at the same time increasing the probability of the delay. This maintains the intensity of the testing. Reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Steven Rostedt <rostedt@goodmis.org> |
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Steven Rostedt
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016a8d5be6 |
rcu: Don't call wakeup() with rcu_node structure ->lock held
This commit fixes a lockdep-detected deadlock by moving a wake_up() call out from a rnp->lock critical section. Please see below for the long version of this story. On Tue, 2013-05-28 at 16:13 -0400, Dave Jones wrote: > [12572.705832] ====================================================== > [12572.750317] [ INFO: possible circular locking dependency detected ] > [12572.796978] 3.10.0-rc3+ #39 Not tainted > [12572.833381] ------------------------------------------------------- > [12572.862233] trinity-child17/31341 is trying to acquire lock: > [12572.870390] (rcu_node_0){..-.-.}, at: [<ffffffff811054ff>] rcu_read_unlock_special+0x9f/0x4c0 > [12572.878859] > but task is already holding lock: > [12572.894894] (&ctx->lock){-.-...}, at: [<ffffffff811390ed>] perf_lock_task_context+0x7d/0x2d0 > [12572.903381] > which lock already depends on the new lock. > > [12572.927541] > the existing dependency chain (in reverse order) is: > [12572.943736] > -> #4 (&ctx->lock){-.-...}: > [12572.960032] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12572.968337] [<ffffffff816ebc90>] _raw_spin_lock+0x40/0x80 > [12572.976633] [<ffffffff8113c987>] __perf_event_task_sched_out+0x2e7/0x5e0 > [12572.984969] [<ffffffff81088953>] perf_event_task_sched_out+0x93/0xa0 > [12572.993326] [<ffffffff816ea0bf>] __schedule+0x2cf/0x9c0 > [12573.001652] [<ffffffff816eacfe>] schedule_user+0x2e/0x70 > [12573.009998] [<ffffffff816ecd64>] retint_careful+0x12/0x2e > [12573.018321] > -> #3 (&rq->lock){-.-.-.}: > [12573.034628] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.042930] [<ffffffff816ebc90>] _raw_spin_lock+0x40/0x80 > [12573.051248] [<ffffffff8108e6a7>] wake_up_new_task+0xb7/0x260 > [12573.059579] [<ffffffff810492f5>] do_fork+0x105/0x470 > [12573.067880] [<ffffffff81049686>] kernel_thread+0x26/0x30 > [12573.076202] [<ffffffff816cee63>] rest_init+0x23/0x140 > [12573.084508] [<ffffffff81ed8e1f>] start_kernel+0x3f1/0x3fe > [12573.092852] [<ffffffff81ed856f>] x86_64_start_reservations+0x2a/0x2c > [12573.101233] [<ffffffff81ed863d>] x86_64_start_kernel+0xcc/0xcf > [12573.109528] > -> #2 (&p->pi_lock){-.-.-.}: > [12573.125675] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.133829] [<ffffffff816ebe9b>] _raw_spin_lock_irqsave+0x4b/0x90 > [12573.141964] [<ffffffff8108e881>] try_to_wake_up+0x31/0x320 > [12573.150065] [<ffffffff8108ebe2>] default_wake_function+0x12/0x20 > [12573.158151] [<ffffffff8107bbf8>] autoremove_wake_function+0x18/0x40 > [12573.166195] [<ffffffff81085398>] __wake_up_common+0x58/0x90 > [12573.174215] [<ffffffff81086909>] __wake_up+0x39/0x50 > [12573.182146] [<ffffffff810fc3da>] rcu_start_gp_advanced.isra.11+0x4a/0x50 > [12573.190119] [<ffffffff810fdb09>] rcu_start_future_gp+0x1c9/0x1f0 > [12573.198023] [<ffffffff810fe2c4>] rcu_nocb_kthread+0x114/0x930 > [12573.205860] [<ffffffff8107a91d>] kthread+0xed/0x100 > [12573.213656] [<ffffffff816f4b1c>] ret_from_fork+0x7c/0xb0 > [12573.221379] > -> #1 (&rsp->gp_wq){..-.-.}: > [12573.236329] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.243783] [<ffffffff816ebe9b>] _raw_spin_lock_irqsave+0x4b/0x90 > [12573.251178] [<ffffffff810868f3>] __wake_up+0x23/0x50 > [12573.258505] [<ffffffff810fc3da>] rcu_start_gp_advanced.isra.11+0x4a/0x50 > [12573.265891] [<ffffffff810fdb09>] rcu_start_future_gp+0x1c9/0x1f0 > [12573.273248] [<ffffffff810fe2c4>] rcu_nocb_kthread+0x114/0x930 > [12573.280564] [<ffffffff8107a91d>] kthread+0xed/0x100 > [12573.287807] [<ffffffff816f4b1c>] ret_from_fork+0x7c/0xb0 Notice the above call chain. rcu_start_future_gp() is called with the rnp->lock held. Then it calls rcu_start_gp_advance, which does a wakeup. You can't do wakeups while holding the rnp->lock, as that would mean that you could not do a rcu_read_unlock() while holding the rq lock, or any lock that was taken while holding the rq lock. This is because... (See below). > [12573.295067] > -> #0 (rcu_node_0){..-.-.}: > [12573.309293] [<ffffffff810b8d36>] __lock_acquire+0x1786/0x1af0 > [12573.316568] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.323825] [<ffffffff816ebc90>] _raw_spin_lock+0x40/0x80 > [12573.331081] [<ffffffff811054ff>] rcu_read_unlock_special+0x9f/0x4c0 > [12573.338377] [<ffffffff810760a6>] __rcu_read_unlock+0x96/0xa0 > [12573.345648] [<ffffffff811391b3>] perf_lock_task_context+0x143/0x2d0 > [12573.352942] [<ffffffff8113938e>] find_get_context+0x4e/0x1f0 > [12573.360211] [<ffffffff811403f4>] SYSC_perf_event_open+0x514/0xbd0 > [12573.367514] [<ffffffff81140e49>] SyS_perf_event_open+0x9/0x10 > [12573.374816] [<ffffffff816f4dd4>] tracesys+0xdd/0xe2 Notice the above trace. perf took its own ctx->lock, which can be taken while holding the rq lock. While holding this lock, it did a rcu_read_unlock(). The perf_lock_task_context() basically looks like: rcu_read_lock(); raw_spin_lock(ctx->lock); rcu_read_unlock(); Now, what looks to have happened, is that we scheduled after taking that first rcu_read_lock() but before taking the spin lock. When we scheduled back in and took the ctx->lock, the following rcu_read_unlock() triggered the "special" code. The rcu_read_unlock_special() takes the rnp->lock, which gives us a possible deadlock scenario. CPU0 CPU1 CPU2 ---- ---- ---- rcu_nocb_kthread() lock(rq->lock); lock(ctx->lock); lock(rnp->lock); wake_up(); lock(rq->lock); rcu_read_unlock(); rcu_read_unlock_special(); lock(rnp->lock); lock(ctx->lock); **** DEADLOCK **** > [12573.382068] > other info that might help us debug this: > > [12573.403229] Chain exists of: > rcu_node_0 --> &rq->lock --> &ctx->lock > > [12573.424471] Possible unsafe locking scenario: > > [12573.438499] CPU0 CPU1 > [12573.445599] ---- ---- > [12573.452691] lock(&ctx->lock); > [12573.459799] lock(&rq->lock); > [12573.467010] lock(&ctx->lock); > [12573.474192] lock(rcu_node_0); > [12573.481262] > *** DEADLOCK *** > > [12573.501931] 1 lock held by trinity-child17/31341: > [12573.508990] #0: (&ctx->lock){-.-...}, at: [<ffffffff811390ed>] perf_lock_task_context+0x7d/0x2d0 > [12573.516475] > stack backtrace: > [12573.530395] CPU: 1 PID: 31341 Comm: trinity-child17 Not tainted 3.10.0-rc3+ #39 > [12573.545357] ffffffff825b4f90 ffff880219f1dbc0 ffffffff816e375b ffff880219f1dc00 > [12573.552868] ffffffff816dfa5d ffff880219f1dc50 ffff88023ce4d1f8 ffff88023ce4ca40 > [12573.560353] 0000000000000001 0000000000000001 ffff88023ce4d1f8 ffff880219f1dcc0 > [12573.567856] Call Trace: > [12573.575011] [<ffffffff816e375b>] dump_stack+0x19/0x1b > [12573.582284] [<ffffffff816dfa5d>] print_circular_bug+0x200/0x20f > [12573.589637] [<ffffffff810b8d36>] __lock_acquire+0x1786/0x1af0 > [12573.596982] [<ffffffff810918f5>] ? sched_clock_cpu+0xb5/0x100 > [12573.604344] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.611652] [<ffffffff811054ff>] ? rcu_read_unlock_special+0x9f/0x4c0 > [12573.619030] [<ffffffff816ebc90>] _raw_spin_lock+0x40/0x80 > [12573.626331] [<ffffffff811054ff>] ? rcu_read_unlock_special+0x9f/0x4c0 > [12573.633671] [<ffffffff811054ff>] rcu_read_unlock_special+0x9f/0x4c0 > [12573.640992] [<ffffffff811390ed>] ? perf_lock_task_context+0x7d/0x2d0 > [12573.648330] [<ffffffff810b429e>] ? put_lock_stats.isra.29+0xe/0x40 > [12573.655662] [<ffffffff813095a0>] ? delay_tsc+0x90/0xe0 > [12573.662964] [<ffffffff810760a6>] __rcu_read_unlock+0x96/0xa0 > [12573.670276] [<ffffffff811391b3>] perf_lock_task_context+0x143/0x2d0 > [12573.677622] [<ffffffff81139070>] ? __perf_event_enable+0x370/0x370 > [12573.684981] [<ffffffff8113938e>] find_get_context+0x4e/0x1f0 > [12573.692358] [<ffffffff811403f4>] SYSC_perf_event_open+0x514/0xbd0 > [12573.699753] [<ffffffff8108cd9d>] ? get_parent_ip+0xd/0x50 > [12573.707135] [<ffffffff810b71fd>] ? trace_hardirqs_on_caller+0xfd/0x1c0 > [12573.714599] [<ffffffff81140e49>] SyS_perf_event_open+0x9/0x10 > [12573.721996] [<ffffffff816f4dd4>] tracesys+0xdd/0xe2 This commit delays the wakeup via irq_work(), which is what perf and ftrace use to perform wakeups in critical sections. Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
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Linus Torvalds
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81db4dbf59 |
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Thomas Gleixner: - Trivial: unused variable removal - Posix-timers: Add the clock ID to the new proc interface to make it useful. The interface is new and should be functional when we reach the final 3.10 release. - Cure a false positive warning in the tick code introduced by the overhaul in 3.10 - Fix for a persistent clock detection regression introduced in this cycle * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timekeeping: Correct run-time detection of persistent_clock. ntp: Remove unused variable flags in __hardpps posix-timers: Show clock ID in proc file tick: Cure broadcast false positive pending bit warning |
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Linus Torvalds
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c3e58a7945 |
irqdomain bug fixes for v3.10-rc4
This branch contains a set of straight forward bug fixes to the irqdomain code and to a couple of drivers that make use of it. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAABAgAGBQJRs51nAAoJEEFnBt12D9kBmnUP/RCgaTn5biRD0tC6OCGwvsZr YKypc71cZtbO3CTk1Sw2jgDUoW+2FWwtbwKWCmrHIaulRuxoeMHLbpc6fEGFRAjG ENnSEuSJkYV2T5ZoYjM5mAjotHUcszxZ9uOz7ovCUY72GO/+tfJ97NT9+CCpPfWV Wa/i08/91UPbWP1ASfMLXVzqO9uqEYvrrvY2PSqJ/g0BkzbybAg38u6IycZkGW4u /mjglx5fYRhcQgl7o1FDaw97AGjbykt2mgP7EK3R24BxvEy4gmn4IzGo9duOf7Y2 b1tEfro/keRoibuKehPWdKTvpda80DUJjrsOwmNveZHTWlSB8GZXqCEmOmTHngrV gNX6MUVZClUvKiQCDo3ibyZUmIuUnnlRee6WqQzr2VsMiwct449Gg81zwXX+Yn7O 5KOnlyicJur3f4HqQSKEA2CXU6RRCmk2iqCFMqtutxy20cmm3LoW7OM7rFF7tzix g6czKZiX+yKwoP2E2EQ2mYM8cirKeEyPhs4EUnKJJOVVZqOCtHkrKnkbSoithsS3 we6Isj8KM8NQ3fgeFsbcxV+ezK3moIzD0fYr3Q6x25VZLYrYH7XpUix0nlGYxCOK vlEpCaMes/IG/+SKElf8fPoxs0qlOYPvYZBrLjUGCG/VB01bNsj0mjKYm1va+f6v n3zQbGS7X+TiiHQ+EFL0 =wZCk -----END PGP SIGNATURE----- Merge tag 'irqdomain-for-linus' of git://git.secretlab.ca/git/linux Pull irqdomain bug fixes from Grant Likely: "This branch contains a set of straight forward bug fixes to the irqdomain code and to a couple of drivers that make use of it." * tag 'irqdomain-for-linus' of git://git.secretlab.ca/git/linux: irqchip: Return -EPERM for reserved IRQs irqdomain: document the simple domain first_irq kernel/irq/irqdomain.c: before use 'irq_data', need check it whether valid. irqdomain: export irq_domain_add_simple |
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Linus Walleij
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94a63da0ac |
irqdomain: document the simple domain first_irq
The first_irq needs to be zero to get a linear domain and that comes with special semantics. We want to simplify this going forward but some documentation never hurts. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Grant Likely <grant.likely@linaro.org> |
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Chen Gang
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275e31b10c |
kernel/irq/irqdomain.c: before use 'irq_data', need check it whether valid.
Since irq_data may be NULL, if so, we WARN_ON(), and continue, 'hwirq' which related with 'irq_data' has to initialize later, or it will cause issue. Signed-off-by: Chen Gang <gang.chen@asianux.com> Signed-off-by: Grant Likely <grant.likely@linaro.org> |
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Arnd Bergmann
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346dbb79ea |
irqdomain: export irq_domain_add_simple
All other irq_domain_add_* functions are exported already, and apparently this one got left out by mistake, which causes build errors for ARM allmodconfig kernels: ERROR: "irq_domain_add_simple" [drivers/gpio/gpio-rcar.ko] undefined! ERROR: "irq_domain_add_simple" [drivers/gpio/gpio-em.ko] undefined! Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Simon Horman <horms+renesas@verge.net.au> Signed-off-by: Grant Likely <grant.likely@linaro.org> |
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Linus Torvalds
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14d0ee0517 |
This contains 4 fixes.
The first two fix the case where full RCU debugging is enabled, enabling function tracing causes a live lock of the system. This is due to the added debug checks in rcu_dereference_raw() that is used by the function tracer. These checks are also traced by the function tracer as well as cause enough overhead to the function tracer to slow down the system enough that the time to finish an interrupt can take longer than when the next interrupt is triggered, causing a live lock from the timer interrupt. Talking this over with Paul McKenney, we came up with a fix that adds a new rcu_dereference_raw_notrace() that does not perform these added checks, and let the function tracer use that. The third commit fixes a failed compile when branch tracing is enabled, due to the conversion of the trace_test_buffer() selftest that the branch trace wasn't converted for. The forth patch fixes a bug caught by the RCU lockdep code where a rcu_read_lock() is performed when rcu is disabled (either going to or from idle, or user space). This happened on the irqsoff tracer as it calls task_uid(). The fix here was to use current_uid() when possible that doesn't use rcu locking. Which luckily, is always used when irqsoff calls this code. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQEcBAABAgAGBQJRsQZhAAoJEOdOSU1xswtMquIH/0zyrqrLTnkc5MsNnnJ8kH5R z1cULts4FqBTUNZ1hdb3BTOu4zywjREIkWfM9qqpBmq9Mq6PBxX7gxWTqYvD4jiX EatiiCKa7Fyddx4iHJNfvtWgKVYt9WKSNeloRugS9h7NxIZ1wpz21DUpENFQzW2f jWRnq/AKXFmZ0vn1953mPePtRsg61RYpb7DCkTE1gtUnvL43wMd/Mo6p6BLMEG26 1dDK6EWO/uewl8A4oP5JZYP+AP5Ckd4x1PuQK682AtQw+8S6etaGfeJr0WZmKQoD 0aDZ/NXXSNKChlUFGJusBNJCWryONToa+sdiKuk1h/lW/k9Mail/FChiHBzMiwk= =uvlD -----END PGP SIGNATURE----- Merge tag 'trace-fixes-v3.10-rc3-v3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: "This contains 4 fixes. The first two fix the case where full RCU debugging is enabled, enabling function tracing causes a live lock of the system. This is due to the added debug checks in rcu_dereference_raw() that is used by the function tracer. These checks are also traced by the function tracer as well as cause enough overhead to the function tracer to slow down the system enough that the time to finish an interrupt can take longer than when the next interrupt is triggered, causing a live lock from the timer interrupt. Talking this over with Paul McKenney, we came up with a fix that adds a new rcu_dereference_raw_notrace() that does not perform these added checks, and let the function tracer use that. The third commit fixes a failed compile when branch tracing is enabled, due to the conversion of the trace_test_buffer() selftest that the branch trace wasn't converted for. The forth patch fixes a bug caught by the RCU lockdep code where a rcu_read_lock() is performed when rcu is disabled (either going to or from idle, or user space). This happened on the irqsoff tracer as it calls task_uid(). The fix here was to use current_uid() when possible that doesn't use rcu locking. Which luckily, is always used when irqsoff calls this code." * tag 'trace-fixes-v3.10-rc3-v3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Use current_uid() for critical time tracing tracing: Fix bad parameter passed in branch selftest ftrace: Use the rcu _notrace variants for rcu_dereference_raw() and friends rcu: Add _notrace variation of rcu_dereference_raw() and hlist_for_each_entry_rcu() |
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Steven Rostedt (Red Hat)
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f17a519485 |
tracing: Use current_uid() for critical time tracing
The irqsoff tracer records the max time that interrupts are disabled. There are hooks in the assembly code that calls back into the tracer when interrupts are disabled or enabled. When they are enabled, the tracer checks if the amount of time they were disabled is larger than the previous recorded max interrupts off time. If it is, it creates a snapshot of the currently running trace to store where the last largest interrupts off time was held and how it happened. During testing, this RCU lockdep dump appeared: [ 1257.829021] =============================== [ 1257.829021] [ INFO: suspicious RCU usage. ] [ 1257.829021] 3.10.0-rc1-test+ #171 Tainted: G W [ 1257.829021] ------------------------------- [ 1257.829021] /home/rostedt/work/git/linux-trace.git/include/linux/rcupdate.h:780 rcu_read_lock() used illegally while idle! [ 1257.829021] [ 1257.829021] other info that might help us debug this: [ 1257.829021] [ 1257.829021] [ 1257.829021] RCU used illegally from idle CPU! [ 1257.829021] rcu_scheduler_active = 1, debug_locks = 0 [ 1257.829021] RCU used illegally from extended quiescent state! [ 1257.829021] 2 locks held by trace-cmd/4831: [ 1257.829021] #0: (max_trace_lock){......}, at: [<ffffffff810e2b77>] stop_critical_timing+0x1a3/0x209 [ 1257.829021] #1: (rcu_read_lock){.+.+..}, at: [<ffffffff810dae5a>] __update_max_tr+0x88/0x1ee [ 1257.829021] [ 1257.829021] stack backtrace: [ 1257.829021] CPU: 3 PID: 4831 Comm: trace-cmd Tainted: G W 3.10.0-rc1-test+ #171 [ 1257.829021] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS SDBLI944.86P 05/08/2007 [ 1257.829021] 0000000000000001 ffff880065f49da8 ffffffff8153dd2b ffff880065f49dd8 [ 1257.829021] ffffffff81092a00 ffff88006bd78680 ffff88007add7500 0000000000000003 [ 1257.829021] ffff88006bd78680 ffff880065f49e18 ffffffff810daebf ffffffff810dae5a [ 1257.829021] Call Trace: [ 1257.829021] [<ffffffff8153dd2b>] dump_stack+0x19/0x1b [ 1257.829021] [<ffffffff81092a00>] lockdep_rcu_suspicious+0x109/0x112 [ 1257.829021] [<ffffffff810daebf>] __update_max_tr+0xed/0x1ee [ 1257.829021] [<ffffffff810dae5a>] ? __update_max_tr+0x88/0x1ee [ 1257.829021] [<ffffffff811002b9>] ? user_enter+0xfd/0x107 [ 1257.829021] [<ffffffff810dbf85>] update_max_tr_single+0x11d/0x12d [ 1257.829021] [<ffffffff811002b9>] ? user_enter+0xfd/0x107 [ 1257.829021] [<ffffffff810e2b15>] stop_critical_timing+0x141/0x209 [ 1257.829021] [<ffffffff8109569a>] ? trace_hardirqs_on+0xd/0xf [ 1257.829021] [<ffffffff811002b9>] ? user_enter+0xfd/0x107 [ 1257.829021] [<ffffffff810e3057>] time_hardirqs_on+0x2a/0x2f [ 1257.829021] [<ffffffff811002b9>] ? user_enter+0xfd/0x107 [ 1257.829021] [<ffffffff8109550c>] trace_hardirqs_on_caller+0x16/0x197 [ 1257.829021] [<ffffffff8109569a>] trace_hardirqs_on+0xd/0xf [ 1257.829021] [<ffffffff811002b9>] user_enter+0xfd/0x107 [ 1257.829021] [<ffffffff810029b4>] do_notify_resume+0x92/0x97 [ 1257.829021] [<ffffffff8154bdca>] int_signal+0x12/0x17 What happened was entering into the user code, the interrupts were enabled and a max interrupts off was recorded. The trace buffer was saved along with various information about the task: comm, pid, uid, priority, etc. The uid is recorded with task_uid(tsk). But this is a macro that uses rcu_read_lock() to retrieve the data, and this happened to happen where RCU is blind (user_enter). As only the preempt and irqs off tracers can have this happen, and they both only have the tsk == current, if tsk == current, use current_uid() instead of task_uid(), as current_uid() does not use RCU as only current can change its uid. This fixes the RCU suspicious splat. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> |
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Linus Torvalds
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7d80fea426 |
Merge branch 'for-3.10-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo: - Fix for yet another xattr bug which may lead to NULL deref. - A subtle bug in for_each_descendant_pre(). This bug requires quite specific conditions to trigger and isn't too likely to actually happen in the wild, but maybe that just makes it that much more nastier. - A warning message added for silly cgroup re-mount (not -o remount, but unmount followed by mount) behavior. * 'for-3.10-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: warn about mismatching options of a new mount of an existing hierarchy cgroup: fix a subtle bug in descendant pre-order walk cgroup: initialize xattr before calling d_instantiate() |
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Jiri Bohac
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f5d00c1f9a |
tick: Remove useless timekeeping duty attribution to broadcast source
Since
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Li Zhong
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1a7f829f09 |
nohz: Fix notifier return val that enforce timekeeping
In tick_nohz_cpu_down_callback() if the cpu is the one handling timekeeping, we must return something that stops the CPU_DOWN_PREPARE notifiers and then start notify CPU_DOWN_FAILED on the already called notifier call backs. However traditional errno values are not handled by the notifier unless these are encapsulated using errno_to_notifier(). Hence the current -EINVAL is misinterpreted and converted to junk after notifier_to_errno(), leaving the notifier subsystem to random behaviour such as eventually allowing the cpu to go down. Fix this by using the standard NOTIFY_BAD instead. Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Frederic Weisbecker
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521921bad1 |
kvm: Move guest entry/exit APIs to context_tracking
The kvm_host.h header file doesn't handle well inclusion when archs don't support KVM. This results in build crashes for such archs when they want to implement context tracking because this subsystem includes kvm_host.h in order to implement the guest_enter/exit APIs but it doesn't handle KVM off case. To fix this, move the guest_enter()/guest_exit() declarations and generic implementation to the context tracking headers. These generic APIs actually belong to this subsystem, besides other domains boundary tracking like user_enter() et al. KVM now properly becomes a user of this library, not the other buggy way around. Reported-by: Kevin Hilman <khilman@linaro.org> Reviewed-by: Kevin Hilman <khilman@linaro.org> Tested-by: Kevin Hilman <khilman@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Frederic Weisbecker
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45eacc6927 |
vtime: Use consistent clocks among nohz accounting
While computing the cputime delta of dynticks CPUs, we are mixing up clocks of differents natures: * local_clock() which takes care of unstable clock sources and fix these if needed. * sched_clock() which is the weaker version of local_clock(). It doesn't compute any fixup in case of unstable source. If the clock source is stable, those two clocks are the same and we can safely compute the difference against two random points. Otherwise it results in random deltas as sched_clock() can randomly drift away, back or forward, from local_clock(). As a consequence, some strange behaviour with unstable tsc has been observed such as non progressing constant zero cputime. (The 'top' command showing no load). Fix this by only using local_clock(), or its irq safe/remote equivalent, in vtime code. Reported-by: Mike Galbraith <efault@gmx.de> Suggested-by: Mike Galbraith <efault@gmx.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Linus Torvalds
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484b002e28 |
Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Peter Anvin: - Three EFI-related fixes - Two early memory initialization fixes - build fix for older binutils - fix for an eager FPU performance regression -- currently we don't allow the use of the FPU at interrupt time *at all* in eager mode, which is clearly wrong. * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86: Allow FPU to be used at interrupt time even with eagerfpu x86, crc32-pclmul: Fix build with older binutils x86-64, init: Fix a possible wraparound bug in switchover in head_64.S x86, range: fix missing merge during add range x86, efi: initial the local variable of DataSize to zero efivar: fix oops in efivar_update_sysfs_entries() caused by memory reuse efivarfs: Never return ENOENT from firmware again |
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Steven Rostedt (Red Hat)
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0184d50f9f |
tracing: Fix bad parameter passed in branch selftest
The branch selftest calls trace_test_buffer(), but with the new code it expects the first parameter to be a pointer to a struct trace_buffer. All self tests were changed but the branch selftest was missed. This caused either a crash or failed test when the branch selftest was enabled. Link: http://lkml.kernel.org/r/20130529141333.GA24064@localhost Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> |
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Thomas Gleixner
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67dd331c5d | Merge branch 'fortglx/3.10/time' of git://git.linaro.org/people/jstultz/linux into timers/urgent | |
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Steven Rostedt
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1bb539ca36 |
ftrace: Use the rcu _notrace variants for rcu_dereference_raw() and friends
As rcu_dereference_raw() under RCU debug config options can add quite a bit of checks, and that tracing uses rcu_dereference_raw(), these checks happen with the function tracer. The function tracer also happens to trace these debug checks too. This added overhead can livelock the system. Have the function tracer use the new RCU _notrace equivalents that do not do the debug checks for RCU. Link: http://lkml.kernel.org/r/20130528184209.467603904@goodmis.org Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> |
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Jeff Liu
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2a0ff3fbe3 |
cgroup: warn about mismatching options of a new mount of an existing hierarchy
With the new __DEVEL__sane_behavior mount option was introduced, if the root cgroup is alive with no xattr function, to mount a new cgroup with xattr will be rejected in terms of design which just fine. However, if the root cgroup does not mounted with __DEVEL__sane_hehavior, to create a new cgroup with xattr option will succeed although after that the EA function does not works as expected but will get ENOTSUPP for setting up attributes under either cgroup. e.g. setfattr: /cgroup2/test: Operation not supported Instead of keeping silence in this case, it's better to drop a log entry in warning level. That would be helpful to understand the reason behind the scene from the user's perspective, and this is essentially an improvement does not break the backward compatibilities. With this fix, above mount attemption will keep up works as usual but the following line cound be found at the system log: [ ...] cgroup: new mount options do not match the existing superblock tj: minor formatting / message updates. Signed-off-by: Jie Liu <jeff.liu@oracle.com> Reported-by: Alexey Kodanev <alexey.kodanev@oracle.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org |
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Zoran Markovic
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0d6bd9953f |
timekeeping: Correct run-time detection of persistent_clock.
Since commit
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Geert Uytterhoeven
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aa848233f7 |
ntp: Remove unused variable flags in __hardpps
kernel/time/ntp.c: In function ‘__hardpps’:
kernel/time/ntp.c:877: warning: unused variable ‘flags’
commit
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Linus Torvalds
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e3bf756eb9 |
Two more fixes:
The first one was reported by Mauro Carvalho Chehab, where if a poll() is done against a trace buffer for a CPU that has never been online, it will crash the kernel, as buffers are only created when a CPU comes on line, but the trace files are for all possible CPUs. This fix is to check if the buffer was allocated and if not return -EINVAL. That was the simple fix, the real fix is a bit more complex and not for a -rc release. We could have the files created when the CPUs come online. That would require some design changes. The second one was reported by Peter Zijlstra. If the kernel command line has ftrace=nop, it will lock up the system on boot up. This is because the new design for 3.10 has the nop tracer bootstrap the tracing subsystem. When ftrace=<trace> is defined, when a that tracer is registered, it starts the tracing, but uses the nop tracer to clear things out. What happened here was that ftrace=nop caused the registering of nop to start it and use nop before it was initialized. The only thing nop needs to have done to initialize it is to have the tracer point its current_tracer structure member to the nop tracer. Doing that before registering the nop tracer makes everything work. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQEcBAABAgAGBQJRpMkPAAoJEOdOSU1xswtMxeEIALWCnqSCKZJ0Oz+2TuR15vd2 Szm/knRBktRG2FizN8FIouXXMLIYM5HFSvO3Q2bWuV4Dv5KaqNcCEL5BggZC/+Rj swt5+rMiUuln0teq792h2LhKwORw0YicLzWsyIZ82iSpcFKAseXqcMzEe/P/Emat +J1QaoeDtOx/3X5Sv6tqHomqR80u7phQJwmIK6Yik389yLo3sy2XiPRk9PJqDpac V9xbCnZlnopm7rLo7pEAI3R6Vn+MX6lrY1MO0xxjqeIvhvxr9nk0WIRnaevyARbt eHnCtfa9pjn+bU9xYaFmyIkilc/IEBFRLb0dtEueH81nmaFDXpHI+h/pEFrDJqE= =PR0j -----END PGP SIGNATURE----- Merge tag 'trace-fixes-v3.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: "Two more fixes: The first one was reported by Mauro Carvalho Chehab, where if a poll() is done against a trace buffer for a CPU that has never been online, it will crash the kernel, as buffers are only created when a CPU comes on line, but the trace files are for all possible CPUs. This fix is to check if the buffer was allocated and if not return -EINVAL. That was the simple fix, the real fix is a bit more complex and not for a -rc release. We could have the files created when the CPUs come online. That would require some design changes. The second one was reported by Peter Zijlstra. If the kernel command line has ftrace=nop, it will lock up the system on boot up. This is because the new design for 3.10 has the nop tracer bootstrap the tracing subsystem. When ftrace=<trace> is defined, when a that tracer is registered, it starts the tracing, but uses the nop tracer to clear things out. What happened here was that ftrace=nop caused the registering of nop to start it and use nop before it was initialized. The only thing nop needs to have done to initialize it is to have the tracer point its current_tracer structure member to the nop tracer. Doing that before registering the nop tracer makes everything work." * tag 'trace-fixes-v3.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ring-buffer: Do not poll non allocated cpu buffers tracing: Fix crash when ftrace=nop on the kernel command line |
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Steven Rostedt (Red Hat)
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6721cb6002 |
ring-buffer: Do not poll non allocated cpu buffers
The tracing infrastructure sets up for possible CPUs, but it uses the ring buffer polling, it is possible to call the ring buffer polling code with a CPU that hasn't been allocated. This will cause a kernel oops when it access a ring buffer cpu buffer that is part of the possible cpus but hasn't been allocated yet as the CPU has never been online. Reported-by: Mauro Carvalho Chehab <mchehab@redhat.com> Tested-by: Mauro Carvalho Chehab <mchehab@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> |
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Peter Zijlstra
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26cb63ad11 |
perf: Fix perf mmap bugs
Vince reported a problem found by his perf specific trinity fuzzer. Al noticed 2 problems with perf's mmap(): - it has issues against fork() since we use vma->vm_mm for accounting. - it has an rb refcount leak on double mmap(). We fix the issues against fork() by using VM_DONTCOPY; I don't think there's code out there that uses this; we didn't hear about weird accounting problems/crashes. If we do need this to work, the previously proposed VM_PINNED could make this work. Aside from the rb reference leak spotted by Al, Vince's example prog was indeed doing a double mmap() through the use of perf_event_set_output(). This exposes another problem, since we now have 2 events with one buffer, the accounting gets screwy because we account per event. Fix this by making the buffer responsible for its own accounting. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Link: http://lkml.kernel.org/r/20130528085548.GA12193@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |