Commit-ID: adf374cf61394dd41c027c74a81f9bef90f7a640 Gitweb: http://git.kernel.org/tip/adf374cf61394dd41c027c74a81f9bef90f7a640 Author: John Stultz <johns...@us.ibm.com> AuthorDate: Thu, 5 Jul 2012 15:12:16 -0400 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Mon, 9 Jul 2012 11:35:38 +0200
hrtimer: Fix clock_was_set so it is safe to call from irq context NOTE: This is a prerequisite patch that's required to address the widely observed leap-second related futex/hrtimer issues. Currently clock_was_set() is unsafe to be called from irq context, as it calls on_each_cpu(). This causes problems when we need to adjust the time from update_wall_time(). To fix this, if clock_was_set is called when irqs are disabled, we schedule a timer to fire for immedately after we're out of interrupt context to then notify the hrtimer subsystem. Reported-by: Jan Engelhardt <jeng...@inai.de> Signed-off-by: John Stultz <johns...@us.ibm.com> Acked-by: Prarit Bhargava <pra...@redhat.com> CC: sta...@vger.kernel.org Link: http://lkml.kernel.org/r/1341515538-5100-2-git-send-email-johns...@us.ibm.com Signed-off-by: Thomas Gleixner <t...@linutronix.de> --- kernel/hrtimer.c | 17 ++++++++++++++++- 1 files changed, 16 insertions(+), 1 deletions(-) diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index ae34bf5..d730678 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -746,7 +746,7 @@ static inline void retrigger_next_event(void *arg) { } * resolution timer interrupts. On UP we just disable interrupts and * call the high resolution interrupt code. */ -void clock_was_set(void) +static void do_clock_was_set(unsigned long data) { #ifdef CONFIG_HIGH_RES_TIMERS /* Retrigger the CPU local events everywhere */ @@ -755,6 +755,21 @@ void clock_was_set(void) timerfd_clock_was_set(); } +static DEFINE_TIMER(clock_was_set_timer, do_clock_was_set , 0, 0); + +void clock_was_set(void) +{ + /* + * We can't call on_each_cpu() from irq context, + * so if irqs are disabled , schedule the clock_was_set + * via a timer_list timer for right after. + */ + if (irqs_disabled()) + mod_timer(&clock_was_set_timer, jiffies); + else + do_clock_was_set(0); +} + /* * During resume we might have to reprogram the high resolution timer * interrupt (on the local CPU): -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
