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authorFrederic Weisbecker <frederic@kernel.org>2020-07-17 17:05:40 +0300
committerThomas Gleixner <tglx@linutronix.de>2020-07-17 22:44:05 +0300
commite2a71bdea81690b6ef11f4368261ec6f5b6891aa (patch)
treec01504c4f71f0701226566f0ab859e5c9bd56097 /kernel/time
parent30c66fc30ee7a98c4f3adf5fb7e213b61884474f (diff)
downloadlinux-e2a71bdea81690b6ef11f4368261ec6f5b6891aa.tar.xz
timer: Fix wheel index calculation on last level
When an expiration delta falls into the last level of the wheel, that delta has be compared against the maximum possible delay and reduced to fit in if necessary. However instead of comparing the delta against the maximum, the code compares the actual expiry against the maximum. Then instead of fixing the delta to fit in, it sets the maximum delta as the expiry value. This can result in various undesired outcomes, the worst possible one being a timer expiring 15 days ahead to fire immediately. Fixes: 500462a9de65 ("timers: Switch to a non-cascading wheel") Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20200717140551.29076-2-frederic@kernel.org
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/timer.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 9a838d38dbe6..df1ff803acc4 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -521,8 +521,8 @@ static int calc_wheel_index(unsigned long expires, unsigned long clk)
* Force expire obscene large timeouts to expire at the
* capacity limit of the wheel.
*/
- if (expires >= WHEEL_TIMEOUT_CUTOFF)
- expires = WHEEL_TIMEOUT_MAX;
+ if (delta >= WHEEL_TIMEOUT_CUTOFF)
+ expires = clk + WHEEL_TIMEOUT_MAX;
idx = calc_index(expires, LVL_DEPTH - 1);
}