diff options
authorSteven Rostedt (Red Hat) <>2015-02-06 14:18:19 -0500
committerSteven Rostedt <>2015-02-07 19:34:55 -0500
commit6c8465a82a605bc692304bab42703017dcfff013 (patch)
parenta05d59a5673339ef6936d6940cdf68172ce75b9f (diff)
x86/tlb/trace: Do not trace on CPU that is offline
When taking a CPU down for suspend and resume, a tracepoint may be called when the CPU has been designated offline. As tracepoints require RCU for protection, they must not be called if the current CPU is offline. Unfortunately, trace_tlb_flush() is called in this scenario as was noted by LOCKDEP: ... Disabling non-boot CPUs ... intel_pstate CPU 1 exiting =============================== smpboot: CPU 1 didn't die... [ INFO: suspicious RCU usage. ] 3.19.0-rc7-next-20150204.1-iniza-small #1 Not tainted ------------------------------- include/trace/events/tlb.h:35 suspicious rcu_dereference_check() usage! other info that might help us debug this: RCU used illegally from offline CPU! rcu_scheduler_active = 1, debug_locks = 0 no locks held by swapper/1/0. stack backtrace: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.19.0-rc7-next-20150204.1-iniza-small #1 Hardware name: SAMSUNG ELECTRONICS CO., LTD. 530U3BI/530U4BI/530U4BH/530U3BI/530U4BI/530U4BH, BIOS 13XK 03/28/2013 0000000000000001 ffff88011a44fe18 ffffffff817e370d 0000000000000011 ffff88011a448290 ffff88011a44fe48 ffffffff810d6847 ffff8800c66b9600 0000000000000001 ffff88011a44c000 ffffffff81cb3900 ffff88011a44fe78 Call Trace: [<ffffffff817e370d>] dump_stack+0x4c/0x65 [<ffffffff810d6847>] lockdep_rcu_suspicious+0xe7/0x120 [<ffffffff810b71a5>] idle_task_exit+0x205/0x2c0 [<ffffffff81054c4e>] play_dead_common+0xe/0x50 [<ffffffff81054ca5>] native_play_dead+0x15/0x140 [<ffffffff8102963f>] arch_cpu_idle_dead+0xf/0x20 [<ffffffff810cd89e>] cpu_startup_entry+0x37e/0x580 [<ffffffff81053e20>] start_secondary+0x140/0x150 intel_pstate CPU 2 exiting ... By converting the tlb_flush tracepoint to a TRACE_EVENT_CONDITION where the condition is cpu_online(smp_processor_id()), we can avoid calling RCU protected code when the CPU is offline. Link: Cc: # 3.17+ Fixes: d17d8f9dedb9 "x86/mm: Add tracepoints for TLB flushes" Reported-by: Sedat Dilek <> Tested-by: Sedat Dilek <> Suggested-by: Paul E. McKenney <> Acked-by: Paul E. McKenney <> Acked-by: Dave Hansen <> Signed-off-by: Steven Rostedt <>
1 files changed, 3 insertions, 1 deletions
diff --git a/include/trace/events/tlb.h b/include/trace/events/tlb.h
index 13391d288107..0e7635765153 100644
--- a/include/trace/events/tlb.h
+++ b/include/trace/events/tlb.h
@@ -13,11 +13,13 @@
{ TLB_LOCAL_SHOOTDOWN, "local shootdown" }, \
{ TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" }
TP_PROTO(int reason, unsigned long pages),
TP_ARGS(reason, pages),
+ TP_CONDITION(cpu_online(smp_processor_id())),
__field( int, reason)
__field(unsigned long, pages)