diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2018-11-01 13:02:38 -0700 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-11-10 07:43:01 -0800 |
commit | 65cb24de03f1c8e00a4fedf416b80a4e8f8a6ef2 (patch) | |
tree | 9bf45e88c5bcd099ced62afc49e22f7633d2ffe7 /kernel/time/posix-cpu-timers.c | |
parent | b0b77fb6c9912d0b97a3c468c52b18d1447062c4 (diff) |
posix-timers: Sanitize overrun handling
[ Upstream commit 78c9c4dfbf8c04883941445a195276bb4bb92c76 ]
The posix timer overrun handling is broken because the forwarding functions
can return a huge number of overruns which does not fit in an int. As a
consequence timer_getoverrun(2) and siginfo::si_overrun can turn into
random number generators.
The k_clock::timer_forward() callbacks return a 64 bit value now. Make
k_itimer::ti_overrun[_last] 64bit as well, so the kernel internal
accounting is correct. 3Remove the temporary (int) casts.
Add a helper function which clamps the overrun value returned to user space
via timer_getoverrun(2) or siginfo::si_overrun limited to a positive value
between 0 and INT_MAX. INT_MAX is an indicator for user space that the
overrun value has been clamped.
Reported-by: Team OWL337 <icytxw@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Link: https://lkml.kernel.org/r/20180626132705.018623573@linutronix.de
[florian: Make patch apply to v4.9.135]
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel/time/posix-cpu-timers.c')
-rw-r--r-- | kernel/time/posix-cpu-timers.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 39008d78927a..21a27bb73587 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -103,7 +103,7 @@ static void bump_cpu_timer(struct k_itimer *timer, continue; timer->it.cpu.expires += incr; - timer->it_overrun += 1 << i; + timer->it_overrun += 1LL << i; delta -= incr; } } |