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ALSA: timer: Reject user params with too small ticks
authorTakashi Iwai <tiwai@suse.de>
Tue, 28 Feb 2017 13:49:07 +0000 (14:49 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 12 Mar 2017 05:41:42 +0000 (06:41 +0100)
commit5ac9276dd15f6aeb55e8eb0ecf6e15759ae1f501
tree2472d4e9328a22fe6abfb509f701a8d4ea2dcf9d
parent51ce9867c2efd422519edb92e6d4ea5276b3f283
ALSA: timer: Reject user params with too small ticks

commit 71321eb3f2d0df4e6c327e0b936eec4458a12054 upstream.

When a user sets a too small ticks with a fine-grained timer like
hrtimer, the kernel tries to fire up the timer irq too frequently.
This may lead to the condensed locks, eventually the kernel spinlock
lockup with warnings.

For avoiding such a situation, we define a lower limit of the
resolution, namely 1ms.  When the user passes a too small tick value
that results in less than that, the kernel returns -EINVAL now.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sound/core/timer.c