From: Peter Zijlstra <[email protected]> Unless the very next line is schedule(), or implies it, one must not use preempt_enable_no_resched(). It can cause a preemption to go missing and thereby cause arbitrary delays, breaking the PREEMPT=y invariant.
Link: http://lkml.kernel.org/r/[email protected] Cc: Waiman Long <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Will Deacon <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: the arch/x86 maintainers <[email protected]> Cc: Davidlohr Bueso <[email protected]> Cc: Tim Chen <[email protected]> Cc: huang ying <[email protected]> Cc: Roman Gushchin <[email protected]> Cc: Alexei Starovoitov <[email protected]> Cc: Daniel Borkmann <[email protected]> Cc: [email protected] Fixes: 2c2d7329d8af ("tracing/ftrace: use preempt_enable_no_resched_notrace in ring_buffer_time_stamp()") Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]> --- kernel/trace/ring_buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 41b6f96e5366..4ee8d8aa3d0f 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -762,7 +762,7 @@ u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu) preempt_disable_notrace(); time = rb_time_stamp(buffer); - preempt_enable_no_resched_notrace(); + preempt_enable_notrace(); return time; } -- 2.20.1
