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authorThomas Gleixner <tglx@linutronix.de>2017-12-21 11:41:31 +0100
committerIngo Molnar <mingo@kernel.org>2018-01-16 02:35:44 +0100
commitd05ca13b8d3f685667b3b1748fa89285466270c5 (patch)
treee44a53dcbdc21c3fa5e2521db648e5e30a81f7ea /kernel/time
parentae67badaa1643253998cb21d5782e4ea7c231a29 (diff)
downloadlinux-d05ca13b8d3f685667b3b1748fa89285466270c5.tar.bz2
hrtimer: Correct blatantly incorrect comment
The protection of a hrtimer which runs its callback against migration to a different CPU has nothing to do with hard interrupt context. The protection against migration of a hrtimer running the expiry callback is the pointer in the cpu_base which holds a pointer to the currently running timer. This pointer is evaluated in the code which potentially switches the timer base and makes sure it's kept on the CPU on which the callback is running. Reported-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: keescook@chromium.org Link: http://lkml.kernel.org/r/20171221104205.7269-3-anna-maria@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/hrtimer.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 1d06d2bde733..7687355c00ff 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1195,9 +1195,9 @@ static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
timer->is_rel = false;
/*
- * Because we run timers from hardirq context, there is no chance
- * they get migrated to another cpu, therefore its safe to unlock
- * the timer base.
+ * The timer is marked as running in the CPU base, so it is
+ * protected against migration to a different CPU even if the lock
+ * is dropped.
*/
raw_spin_unlock(&cpu_base->lock);
trace_hrtimer_expire_entry(timer, now);