Messages in this thread Patch in this message | | | Date | Tue, 16 Dec 2008 22:08:58 +0100 | From | Frederic Weisbecker <> | Subject | [PATCH] tracing/ftrace: use preempt_enable_no_resched_notrace in ring_buffer_time_stamp() |
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Impact: prevent a trace recursion
After some tests with function graph tracer under x86-32, I saw some recursions caused by ring_buffer_time_stamp() that calls preempt_enable_no_notrace() which calls preempt_schedule() which is traced itself.
This patch re-enables preemption without rescheduling.
Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> --- kernel/trace/ring_buffer.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 822fcd4..a775e46 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -109,7 +109,7 @@ u64 ring_buffer_time_stamp(int cpu) preempt_disable_notrace(); /* shift to debug/test normalization and TIME_EXTENTS */ time = sched_clock() << DEBUG_SHIFT; - preempt_enable_notrace(); + preempt_enable_no_resched_notrace(); return time; } -- 1.6.0.4
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