Hi, On 09/12/2013 01:50 AM, John Stultz wrote: [...]
The deadlock was introduced by 06c017fdd4dc48451a (timekeeping: Hold timekeepering locks in do_adjtimex and hardpps) in 3.10 This patch avoids this deadlock, by moving the call to schedule_delayed_work() outside of the timekeeper lock critical section. Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Gerlando Falauto <gerlando.falauto@xxxxxxxxxxx> Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Cc: stable <stable@xxxxxxxxxxxxxxx> #3.11, 3.10 Reported-by: Gerlando Falauto <gerlando.falauto@xxxxxxxxxxx> Tested-by: Lin Ming <minggr@xxxxxxxxx> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
For what it's worth (I guess it's a bit late now): Tested-by: Gerlando Falauto <gerlando.falauto@xxxxxxxxxxx> Thanks! Gerlando
--- include/linux/timex.h | 1 + kernel/time/ntp.c | 6 ++---- kernel/time/timekeeping.c | 2 ++ 3 files changed, 5 insertions(+), 4 deletions(-) diff --git a/include/linux/timex.h b/include/linux/timex.h index b3726e6..dd3edd7 100644 --- a/include/linux/timex.h +++ b/include/linux/timex.h @@ -141,6 +141,7 @@ extern int do_adjtimex(struct timex *); extern void hardpps(const struct timespec *, const struct timespec *); int read_current_timer(unsigned long *timer_val); +void ntp_notify_cmos_timer(void); /* The clock frequency of the i8253/i8254 PIT */ #define PIT_TICK_RATE 1193182ul diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 8f5b3b9..bb22151 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -516,13 +516,13 @@ static void sync_cmos_clock(struct work_struct *work) schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next)); } -static void notify_cmos_timer(void) +void ntp_notify_cmos_timer(void) { schedule_delayed_work(&sync_cmos_work, 0); } #else -static inline void notify_cmos_timer(void) { } +void ntp_notify_cmos_timer(void) { } #endif @@ -687,8 +687,6 @@ int __do_adjtimex(struct timex *txc, struct timespec *ts, s32 *time_tai) if (!(time_status & STA_NANO)) txc->time.tv_usec /= NSEC_PER_USEC; - notify_cmos_timer(); - return result; } diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 48b9fff..947ba25 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1703,6 +1703,8 @@ int do_adjtimex(struct timex *txc) write_seqcount_end(&timekeeper_seq); raw_spin_unlock_irqrestore(&timekeeper_lock, flags); + ntp_notify_cmos_timer(); + return ret; }
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