In hwdep interface of firewire-tascam driver, accessing to user space is
in a critical section with disabled local interrupt. Depending on
architecture, accessing to user space can cause page fault exception. Then
local processor stores machine status and handle the synchronous event. A
handler corresponding to the event can call task scheduler to wait for
preparing pages. In a case of usage of single core processor, the state to
disable local interrupt is worse because it doesn't handle usual interrupts
from hardware.
This commit fixes this bug, by performing the accessing outside spinlock.
Reported-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
Cc: stable@vger.kernel.org
Fixes: e5e0c3dd257b('ALSA: firewire-tascam: add hwdep interface')
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit adds hwdep interface so as the other IEEE 1394 sound devices
has.
This interface is designed for mixer/control applications. By using this
interface, an application can get information about firewire node, can
lock/unlock kernel streaming and can get notification at starting/stopping
kernel streaming.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Takashi Sakamoto