From mboxrd@z Thu Jan 1 00:00:00 1970 From: john.stultz@linaro.org (John Stultz) Date: Thu, 2 Jan 2014 15:11:14 -0800 Subject: [PATCH 2/2] sched_clock: Disable seqlock lockdep usage in sched_clock In-Reply-To: <1388704274-5278-1-git-send-email-john.stultz@linaro.org> References: <52C5E675.80701@linaro.org> <1388704274-5278-1-git-send-email-john.stultz@linaro.org> Message-ID: <1388704274-5278-2-git-send-email-john.stultz@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Unforunately the seqlock lockdep enablmenet can't be used in sched_clock, since the lockdep infrastructure eventually calls into sched_clock, which causes a deadlock. Thus, this patch changes all generic sched_clock usage to use the raw_* methods. Cc: Krzysztof Ha?asa Cc: Uwe Kleine-K?nig Cc: Willy Tarreau Cc: Ingo Molnar , Cc: Peter Zijlstra Cc: Stephen Boyd Cc: Linus Torvalds Cc: linux-arm-kernel at lists.infradead.org Reported-by: Krzysztof Ha?asa Signed-off-by: John Stultz --- kernel/time/sched_clock.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c index 68b7993..0abb364 100644 --- a/kernel/time/sched_clock.c +++ b/kernel/time/sched_clock.c @@ -74,7 +74,7 @@ unsigned long long notrace sched_clock(void) return cd.epoch_ns; do { - seq = read_seqcount_begin(&cd.seq); + seq = raw_read_seqcount_begin(&cd.seq); epoch_cyc = cd.epoch_cyc; epoch_ns = cd.epoch_ns; } while (read_seqcount_retry(&cd.seq, seq)); @@ -99,10 +99,10 @@ static void notrace update_sched_clock(void) cd.mult, cd.shift); raw_local_irq_save(flags); - write_seqcount_begin(&cd.seq); + raw_write_seqcount_begin(&cd.seq); cd.epoch_ns = ns; cd.epoch_cyc = cyc; - write_seqcount_end(&cd.seq); + raw_write_seqcount_end(&cd.seq); raw_local_irq_restore(flags); } -- 1.8.3.2