tracing/branch-tracer: fix a trace recursion on branch tracer
Impact: fix crash when enabling the branch-tracer
When the branch tracer inserts an event through
probe_likely_condition(), it calls local_irq_save() and then results
in a trace recursion.
local_irq_save() -> trace_hardirqs_off() -> trace_hardirqs_off_caller()
-> unlikely()
The trace_branch.c file is protected by DISABLE_BRANCH_PROFILING but
that doesn't prevent from external call to functions that use
unlikely().
My box crashed each time I tried to set this tracer (sudden and hard
reboot).
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index 8526555..2511e32 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -41,7 +41,7 @@
if (unlikely(!tr))
return;
- local_irq_save(flags);
+ raw_local_irq_save(flags);
cpu = raw_smp_processor_id();
if (atomic_inc_return(&tr->data[cpu]->disabled) != 1)
goto out;
@@ -73,7 +73,7 @@
out:
atomic_dec(&tr->data[cpu]->disabled);
- local_irq_restore(flags);
+ raw_local_irq_restore(flags);
}
static inline