On Mon, Jul 20, 2015 at 06:14:27PM -0400, Sasha Levin wrote:
> On 05/19/2015 03:17 AM, tip-bot for Frederic Weisbecker wrote:
> > Commit-ID: b30f0e3ffedfa52b1d67a302ae5860c49998e5e2
> > sched/preempt: Optimize preemption operations on __schedule() callers
> >
> I was seeing RCU stall warnings that appeared to have different backtrace
> each time, but would reliably trigger when fuzzing and looked something like
> this:
> [4394886.426627] preempt_schedule_irq (./arch/x86/include/asm/paravirt.h:807
> kernel/sched/core.c:3218)
The only 'obvious' difference there seems to be something like the
below. Prior to the patch preempt_schedule_irq() used
__preempt_count_{add,sub}() which are the !tracing versions.
Does this make it go again? If not, can you provide a .config?
---
include/linux/preempt.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 84991f185173..235a9f2d76fe 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -139,14 +139,14 @@ extern void preempt_count_sub(int val);
#define preempt_active_enter() \
do { \
- preempt_count_add(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET); \
+ __preempt_count_add(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET); \
barrier(); \
} while (0)
#define preempt_active_exit() \
do { \
barrier(); \
- preempt_count_sub(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET); \
+ __preempt_count_sub(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET); \
} while (0)
#ifdef CONFIG_PREEMPT_COUNT
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
