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author | Thomas Gleixner <tglx@linutronix.de> | 2017-05-30 21:15:34 (GMT) |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-06-24 05:11:17 (GMT) |
commit | 8ee7f06f4dcaad729ecd7562b10b9a816f99ae70 (patch) | |
tree | 7ed38e387788e0deb295ee298be47e8ecc21f960 /drivers/usb | |
parent | 766283254b672293fa39b5cecd6a5f86efd75127 (diff) | |
download | linux-8ee7f06f4dcaad729ecd7562b10b9a816f99ae70.tar.xz |
alarmtimer: Prevent overflow of relative timers
commit f4781e76f90df7aec400635d73ea4c35ee1d4765 upstream.
Andrey reported a alartimer related RCU stall while fuzzing the kernel with
syzkaller.
The reason for this is an overflow in ktime_add() which brings the
resulting time into negative space and causes immediate expiry of the
timer. The following rearm with a small interval does not bring the timer
back into positive space due to the same issue.
This results in a permanent firing alarmtimer which hogs the CPU.
Use ktime_add_safe() instead which detects the overflow and clamps the
result to KTIME_SEC_MAX.
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kostya Serebryany <kcc@google.com>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Link: http://lkml.kernel.org/r/20170530211655.802921648@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb')
0 files changed, 0 insertions, 0 deletions