Commit-ID: d05ca13b8d3f685667b3b1748fa89285466270c5 Gitweb: https://git.kernel.org/tip/d05ca13b8d3f685667b3b1748fa89285466270c5 Author: Thomas Gleixner <[email protected]> AuthorDate: Thu, 21 Dec 2017 11:41:31 +0100 Committer: Ingo Molnar <[email protected]> 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 <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Anna-Maria Gleixner <[email protected]> Reviewed-by: Frederic Weisbecker <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: John Stultz <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- 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);
