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 05:37:24 +0000 (06:37 +0100)
commit9879f9d01a3c608f75596437f2c4ae4b218da9dd
tree2d3b3f5422fe7f383939d21b6c4d30f419ab0cea
parentb9bf1f0657c55d91d681c362f4f8c51d6668e5fa
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