Messages in this thread Patch in this message | | | Date | Sat, 12 Feb 2011 01:36:47 GMT | From | tip-bot for Peter Zijlstra <> | Subject | [tip:perf/urgent] x86: Fix text_poke_smp_batch() deadlock |
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Commit-ID: d91309f69b7bdb64aeb30106fde8d18c5dd354b5 Gitweb: http://git.kernel.org/tip/d91309f69b7bdb64aeb30106fde8d18c5dd354b5 Author: Peter Zijlstra <peterz@infradead.org> AuthorDate: Fri, 11 Feb 2011 22:07:46 +0100 Committer: Ingo Molnar <mingo@elte.hu> CommitDate: Sat, 12 Feb 2011 02:34:34 +0100
x86: Fix text_poke_smp_batch() deadlock
Fix this deadlock - we are already holding the mutex:
======================================================= [ INFO: possible circular locking dependency detected ] 2.6.38-rc4-test+ #1 ------------------------------------------------------- bash/1850 is trying to acquire lock: (text_mutex){+.+.+.}, at: [<ffffffff8100a9c1>] return_to_handler+0x0/0x2f
but task is already holding lock: (smp_alt){+.+...}, at: [<ffffffff8100a9c1>] return_to_handler+0x0/0x2f
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (smp_alt){+.+...}: [<ffffffff81082d02>] lock_acquire+0xcd/0xf8 [<ffffffff8192e119>] __mutex_lock_common+0x4c/0x339 [<ffffffff8192e4ca>] mutex_lock_nested+0x3e/0x43 [<ffffffff8101050f>] alternatives_smp_switch+0x77/0x1d8 [<ffffffff81926a6f>] do_boot_cpu+0xd7/0x762 [<ffffffff819277dd>] native_cpu_up+0xe6/0x16a [<ffffffff81928e28>] _cpu_up+0x9d/0xee [<ffffffff81928f4c>] cpu_up+0xd3/0xe7 [<ffffffff82268d4b>] kernel_init+0xe8/0x20a [<ffffffff8100ba24>] kernel_thread_helper+0x4/0x10
-> #1 (cpu_hotplug.lock){+.+.+.}: [<ffffffff81082d02>] lock_acquire+0xcd/0xf8 [<ffffffff8192e119>] __mutex_lock_common+0x4c/0x339 [<ffffffff8192e4ca>] mutex_lock_nested+0x3e/0x43 [<ffffffff810568cc>] get_online_cpus+0x41/0x55 [<ffffffff810a1348>] stop_machine+0x1e/0x3e [<ffffffff819314c1>] text_poke_smp_batch+0x3a/0x3c [<ffffffff81932b6c>] arch_optimize_kprobes+0x10d/0x11c [<ffffffff81933a51>] kprobe_optimizer+0x152/0x222 [<ffffffff8106bb71>] process_one_work+0x1d3/0x335 [<ffffffff8106cfae>] worker_thread+0x104/0x1a4 [<ffffffff810707c4>] kthread+0x9d/0xa5 [<ffffffff8100ba24>] kernel_thread_helper+0x4/0x10
-> #0 (text_mutex){+.+.+.}:
other info that might help us debug this:
6 locks held by bash/1850: #0: (&buffer->mutex){+.+.+.}, at: [<ffffffff8100a9c1>] return_to_handler+0x0/0x2f #1: (s_active#75){.+.+.+}, at: [<ffffffff8100a9c1>] return_to_handler+0x0/0x2f #2: (x86_cpu_hotplug_driver_mutex){+.+.+.}, at: [<ffffffff8100a9c1>] return_to_handler+0x0/0x2f #3: (cpu_add_remove_lock){+.+.+.}, at: [<ffffffff8100a9c1>] return_to_handler+0x0/0x2f #4: (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff8100a9c1>] return_to_handler+0x0/0x2f #5: (smp_alt){+.+...}, at: [<ffffffff8100a9c1>] return_to_handler+0x0/0x2f
stack backtrace: Pid: 1850, comm: bash Not tainted 2.6.38-rc4-test+ #1 Call Trace:
[<ffffffff81080eb2>] print_circular_bug+0xa8/0xb7 [<ffffffff8192e4ca>] mutex_lock_nested+0x3e/0x43 [<ffffffff81010302>] alternatives_smp_unlock+0x3d/0x93 [<ffffffff81010630>] alternatives_smp_switch+0x198/0x1d8 [<ffffffff8102568a>] native_cpu_die+0x65/0x95 [<ffffffff818cc4ec>] _cpu_down+0x13e/0x202 [<ffffffff8117a619>] sysfs_write_file+0x108/0x144 [<ffffffff8111f5a2>] vfs_write+0xac/0xff [<ffffffff8111f7a9>] sys_write+0x4a/0x6e
Reported-by: Steven Rostedt <rostedt@goodmis.org> Tested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: mathieu.desnoyers@efficios.com Cc: rusty@rustcorp.com.au Cc: ananth@in.ibm.com Cc: masami.hiramatsu.pt@hitachi.com Cc: fweisbec@gmail.com Cc: jbeulich@novell.com Cc: jbaron@redhat.com Cc: mhiramat@redhat.com LKML-Reference: <1297458466.5226.93.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- arch/x86/kernel/alternative.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 1236085..7038b95 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -671,7 +671,7 @@ void __kprobes text_poke_smp_batch(struct text_poke_param *params, int n) atomic_set(&stop_machine_first, 1); wrote_text = 0; - stop_machine(stop_machine_text_poke, (void *)&tpp, NULL); + __stop_machine(stop_machine_text_poke, (void *)&tpp, NULL); } #if defined(CONFIG_DYNAMIC_FTRACE) || defined(HAVE_JUMP_LABEL)
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