The following commit has been merged into the timers/core branch of tip: Commit-ID: 406dd42bd1ba0c01babf9cde169bb319e52f6147 Gitweb: https://git.kernel.org/tip/406dd42bd1ba0c01babf9cde169bb319e52f6147 Author: Frederic Weisbecker <frederic@xxxxxxxxxx> AuthorDate: Mon, 26 Jul 2021 14:55:10 +02:00 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitterDate: Tue, 10 Aug 2021 17:09:59 +02:00 posix-cpu-timers: Force next expiration recalc after itimer reset When an itimer deactivates a previously armed expiration, it simply doesn't do anything. As a result the process wide cputime counter keeps running and the tick dependency stays set until it reaches the old ghost expiration value. This can be reproduced with the following snippet: void trigger_process_counter(void) { struct itimerval n = {}; n.it_value.tv_sec = 100; setitimer(ITIMER_VIRTUAL, &n, NULL); n.it_value.tv_sec = 0; setitimer(ITIMER_VIRTUAL, &n, NULL); } Fix this with resetting the relevant base expiration. This is similar to disarming a timer. Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210726125513.271824-4-frederic@xxxxxxxxxx --- kernel/time/posix-cpu-timers.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 61c78b6..5c71322 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -1379,8 +1379,6 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clkid, } } - if (!*newval) - return; *newval += now; }
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