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)
committerJiri Slaby <jslaby@suse.cz>
Mon, 13 Mar 2017 20:40:22 +0000 (21:40 +0100)
commita1449d26f610373e7c339fde3d21df64f9472b2c
treefebe049e5be80a55af30f09139d5202badf40843
parent4a1fd6c6ec27a59512f11111c1e921add17820dc
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: Jiri Slaby <jslaby@suse.cz>
sound/core/timer.c