posix-cpu-timers: Prevent spuriously armed 0-value itimer
authorFrederic Weisbecker <frederic@kernel.org>
Mon, 13 Sep 2021 14:53:32 +0000 (16:53 +0200)
committerThomas Gleixner <tglx@linutronix.de>
Thu, 23 Sep 2021 09:53:51 +0000 (11:53 +0200)
commit8cd9da85d2bd87ce889043e7b1735723dd10eb89
tree6c3861d6c7546018bb4bae808aea793a3d95287b
parente4e737bb5c170df6135a127739a9e6148ee3da82
posix-cpu-timers: Prevent spuriously armed 0-value itimer

Resetting/stopping an itimer eventually leads to it being reprogrammed
with an actual "0" value. As a result the itimer expires on the next
tick, triggering an unexpected signal.

To fix this, make sure that
struct signal_struct::it[CPUCLOCK_PROF/VIRT]::expires is set to 0 when
setitimer() passes a 0 it_value, indicating that the timer must stop.

Fixes: 406dd42bd1ba ("posix-cpu-timers: Force next expiration recalc after itimer reset")
Reported-by: Victor Stinner <vstinner@redhat.com>
Reported-by: Chris Hixon <linux-kernel-bugs@hixontech.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210913145332.232023-1-frederic@kernel.org
kernel/time/posix-cpu-timers.c