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authorTakashi Iwai <tiwai@suse.de>2016-01-28 07:54:16 +0100
committerJiri Slaby <jslaby@suse.cz>2016-02-15 17:07:52 +0100
commit45d0f31cfeadeb31b3023c1919cda0d435d4bf31 (patch)
tree90fc528fc67b8d887b44abbf4fe6730cc7a8ffab /sound
parent7e7e76a343578d96fc3ece56eeb2931273983de9 (diff)
ALSA: dummy: Disable switching timer backend via sysfs
commit 7ee96216c31aabe1eb42fb91ff50dae9fcd014b2 upstream. 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> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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 915b4d7fbb23..f4d626c05071 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