From: Viresh Kumar Date: Mon, 12 May 2014 08:12:29 +0000 (+0530) Subject: hrtimer: Set expiry time before switch_hrtimer_base() X-Git-Tag: firefly_0821_release~3679^2~2224 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=1c0301d184e2ea36aa82917c9c43ea1c3f547a02;p=firefly-linux-kernel-4.4.55.git hrtimer: Set expiry time before switch_hrtimer_base() commit 84ea7fe37908254c3bd90910921f6e1045c1747a upstream. switch_hrtimer_base() calls hrtimer_check_target() which ensures that we do not migrate a timer to a remote cpu if the timer expires before the current programmed expiry time on that remote cpu. But __hrtimer_start_range_ns() calls switch_hrtimer_base() before the new expiry time is set. So the sanity check in hrtimer_check_target() is operating on stale or even uninitialized data. Update expiry time before calling switch_hrtimer_base(). [ tglx: Rewrote changelog once again ] Signed-off-by: Viresh Kumar Cc: linaro-kernel@lists.linaro.org Cc: linaro-networking@linaro.org Cc: fweisbec@gmail.com Cc: arvind.chauhan@arm.com Link: http://lkml.kernel.org/r/81999e148745fc51bbcd0615823fbab9b2e87e23.1399882253.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index bd27a06299b4..aadf4b7a607c 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -999,11 +999,8 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, /* Remove an active timer from the queue: */ ret = remove_hrtimer(timer, base); - /* Switch the timer base, if necessary: */ - new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED); - if (mode & HRTIMER_MODE_REL) { - tim = ktime_add_safe(tim, new_base->get_time()); + tim = ktime_add_safe(tim, base->get_time()); /* * CONFIG_TIME_LOW_RES is a temporary way for architectures * to signal that they simply return xtime in @@ -1018,6 +1015,9 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, hrtimer_set_expires_range_ns(timer, tim, delta_ns); + /* Switch the timer base, if necessary: */ + new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED); + timer_stats_hrtimer_set_start_info(timer); leftmost = enqueue_hrtimer(timer, new_base);