From 072b40a15616fe6bea68466e6bffcfcbf5c8f26f Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 16 Nov 2008 05:59:52 +0100 Subject: [PATCH] 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 Signed-off-by: Ingo Molnar --- kernel/trace/trace_branch.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c index 85265553918f..2511e32572ca 100644 --- a/kernel/trace/trace_branch.c +++ b/kernel/trace/trace_branch.c @@ -41,7 +41,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect) 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 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect) out: atomic_dec(&tr->data[cpu]->disabled); - local_irq_restore(flags); + raw_local_irq_restore(flags); } static inline