Messages in this thread Patch in this message | | | From | Denis Kirjanov <> | Subject | [PATCH v2 2/2] tracing/rcu: don't trace rcu_callback on offline CPUs | Date | Sun, 14 Feb 2016 09:50:18 +0300 |
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Tracepoints use RCU for protection and they must not be called on offline CPUS. So make this tracepoint conditional.
NFO: suspicious RCU usage. ] [ 413.344670] 4.4.0-00006-g0fe53e8-dirty #33 Tainted: G S [ 413.344672] ------------------------------- [ 413.344673] include/trace/events/rcu.h:457 suspicious rcu_dereference_check() usage! [ 413.344674] other info that might help us debug this:
[ 413.344676] RCU used illegally from offline CPU! rcu_scheduler_active = 1, debug_locks = 1 [ 413.344678] no locks held by swapper/4/0. [ 413.344679] stack backtrace: [ 413.344682] CPU: 4 PID: 0 Comm: swapper/4 Tainted: G S 4.4.0-00006-g0fe53e8-dirty #33 [ 413.344683] Call Trace: [ 413.344692] [c0000005b76b7800] [c0000000008bb080] .dump_stack+0x98/0xd4 (unreliable) [ 413.344698] [c0000005b76b7880] [c00000000010c8b8] .lockdep_rcu_suspicious+0x108/0x170 [ 413.344703] [c0000005b76b7910] [c00000000013b9e4] .__call_rcu.constprop.60+0x264/0x600 [ 413.344708] [c0000005b76b79e0] [c0000000002bceec] .put_object+0x5c/0x80 [ 413.344712] [c0000005b76b7a60] [c00000000029a368] .kmem_cache_free+0x298/0x450 [ 413.344716] [c0000005b76b7b00] [c000000000093494] .__mmdrop+0x54/0x150 [ 413.344720] [c0000005b76b7b90] [c0000000000e4010] .idle_task_exit+0x130/0x140 [ 413.344725] [c0000005b76b7c20] [c000000000075804] .pseries_mach_cpu_die+0x64/0x310 [ 413.344730] [c0000005b76b7cd0] [c000000000043e7c] .cpu_die+0x3c/0x60 [ 413.344734] [c0000005b76b7d40] [c0000000000188d8] .arch_cpu_idle_dead+0x28/0x40 [ 413.344738] [c0000005b76b7db0] [c000000000101e8c] .cpu_startup_entry+0x50c/0x560 [ 413.344741] [c0000005b76b7ed0] [c000000000043bd8] .start_secondary+0x328/0x360 [ 413.344746] [c0000005b76b7f90] [c000000000008a6c] start_secondary_prolog+0x10/0x14
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org> ---
v2: Fix the build error that was made while sending the pacthes from another machine
include/trace/events/rcu.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index ef72c4a..793d306b 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -428,13 +428,15 @@ TRACE_EVENT(rcu_prep_idle, * number of lazy callbacks queued, and the fourth element is the * total number of callbacks queued. */ -TRACE_EVENT(rcu_callback, +TRACE_EVENT_CONDITION(rcu_callback, TP_PROTO(const char *rcuname, struct rcu_head *rhp, long qlen_lazy, long qlen), TP_ARGS(rcuname, rhp, qlen_lazy, qlen), + TP_CONDITION(cpu_online(raw_smp_processor_id())), + TP_STRUCT__entry( __field(const char *, rcuname) __field(void *, rhp) -- 2.4.0
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