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authorFrederic Weisbecker <fweisbec@gmail.com>2008-11-15 02:37:44 +0100
committerIngo Molnar <mingo@elte.hu>2008-11-16 07:57:37 +0100
commitb01c746617da5e260803eb10ed64ca043e9a1241 (patch)
tree7b835904f337778b604048169dd064a87149aa99 /arch/x86
parent985809608f758a8d3ddda4ce5a53ed0e57fb9e1b (diff)
tracing/function-return-tracer: add a barrier to ensure return stack index is incremented in memory
Impact: fix possible race condition in ftrace function return tracer This fixes a possible race condition if index incrementation is not immediately flushed in memory. Thanks for Andi Kleen and Steven Rostedt for pointing out this issue and give me this solution. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/ftrace.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 762222ad1387..d98b5a8ecf4c 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -56,6 +56,7 @@ static int push_return_trace(unsigned long ret, unsigned long long time,
return -EBUSY;
index = ++ti->curr_ret_stack;
+ barrier();
ti->ret_stack[index].ret = ret;
ti->ret_stack[index].func = func;
ti->ret_stack[index].calltime = time;