Commit-ID: d05ca13b8d3f685667b3b1748fa89285466270c5 Gitweb: https://git.kernel.org/tip/d05ca13b8d3f685667b3b1748fa89285466270c5 Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Thu, 21 Dec 2017 11:41:31 +0100 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Tue, 16 Jan 2018 02:35:44 +0100 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@xxxxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx> Reviewed-by: Frederic Weisbecker <frederic@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: John Stultz <john.stultz@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: keescook@xxxxxxxxxxxx Link: http://lkml.kernel.org/r/20171221104205.7269-3-anna-maria@xxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- kernel/time/hrtimer.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 1d06d2b..7687355 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); -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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