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rcu, ftrace: Fix RCU lockdep splat in ftrace_perf_buf_prepare()

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Change the pair of rcu_dereference() calls in
ftrace_perf_buf_prepare() to rcu_dereference_sched().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1267667418-32233-3-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Paul E. McKenney 2010-03-03 17:50:18 -08:00 committed by Ingo Molnar
parent 99ee4ca746
commit 8d53dd546f
2 changed files with 4 additions and 4 deletions
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4
include/trace/ftrace.h
View File

@ -699,9 +699,9 @@ __attribute__((section("_ftrace_events"))) event_##call = { \
* __cpu = smp_processor_id();
*
* if (in_nmi())
* trace_buf = rcu_dereference(perf_trace_buf_nmi);
* trace_buf = rcu_dereference_sched(perf_trace_buf_nmi);
* else
* trace_buf = rcu_dereference(perf_trace_buf);
* trace_buf = rcu_dereference_sched(perf_trace_buf);
*
* if (!trace_buf)
* goto end;

4
kernel/trace/trace_event_profile.c
View File

@ -138,9 +138,9 @@ __kprobes void *ftrace_perf_buf_prepare(int size, unsigned short type,
cpu = smp_processor_id();
if (in_nmi())
trace_buf = rcu_dereference(perf_trace_buf_nmi);
trace_buf = rcu_dereference_sched(perf_trace_buf_nmi);
else
trace_buf = rcu_dereference(perf_trace_buf);
trace_buf = rcu_dereference_sched(perf_trace_buf);
if (!trace_buf)
goto err;