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)
committerBen Hutchings <ben@decadent.org.uk>
Mon, 5 Jun 2017 20:13:52 +0000 (21:13 +0100)
commit6192d8b51aa85f9947d2203ea02b4dccfd083ee7
tree1ad38486558865a1524f829b8ddd74d6af6eceba
parenta1d473c07d276b23c573c8a2a87c7e7f8502a295
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: Ben Hutchings <ben@decadent.org.uk>
sound/core/timer.c