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authorTakashi Iwai <tiwai@suse.de>2016-01-28 07:54:16 +0100
committerSasha Levin <sasha.levin@oracle.com>2016-02-15 15:45:26 -0500
commitf6b4419806e546fb02f91bed03572362e2623879 (patch)
treed43cf38b48276073e3b7f9c68f6d1d012b5a7009 /sound
parent2fbdb6c658f4a10c649fd57c42a5199d2a8032d8 (diff)
ALSA: dummy: Disable switching timer backend via sysfs
[ Upstream commit 7ee96216c31aabe1eb42fb91ff50dae9fcd014b2 ] ALSA dummy driver can switch the timer backend between system timer and hrtimer via its hrtimer module option. This can be also switched dynamically via sysfs, but it may lead to a memory corruption when switching is done while a PCM stream is running; the stream instance for the newly switched timer method tries to access the memory that was allocated by another timer method although the sizes differ. As the simplest fix, this patch just disables the switch via sysfs by dropping the writable bit. BugLink: http://lkml.kernel.org/r/CACT4Y+ZGEeEBntHW5WHn2GoeE0G_kRrCmUh6=dWyy-wfzvuJLg@mail.gmail.com Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'sound')
-rw-r--r--sound/drivers/dummy.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/sound/drivers/dummy.c b/sound/drivers/dummy.c
index d11baaf0f0b4..96592d5ba7bf 100644
--- a/sound/drivers/dummy.c
+++ b/sound/drivers/dummy.c
@@ -87,7 +87,7 @@ MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-128) for dummy driver.");
module_param(fake_buffer, bool, 0444);
MODULE_PARM_DESC(fake_buffer, "Fake buffer allocations.");
#ifdef CONFIG_HIGH_RES_TIMERS
-module_param(hrtimer, bool, 0644);
+module_param(hrtimer, bool, 0444);
MODULE_PARM_DESC(hrtimer, "Use hrtimer as the timer source.");
#endif