• Takashi Sakamoto's avatar
    ALSA: fireworks: accessing to user space outside spinlock · 6b1ca4bc
    Takashi Sakamoto authored
    In hwdep interface of fireworks 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 handles 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 don't handle usual interrupts
    from hardware.
    This commit fixes this bug, performing the accessing outside spinlock. This
    commit also gives up counting the number of queued response messages to
    simplify ring-buffer management.
    Reported-by: 's avatarVaishali Thakkar <vaishali.thakkar@oracle.com>
    Cc: stable@vger.kernel.org
    Fixes: 555e8a8f('ALSA: fireworks: Add command/response functionality into hwdep interface')
    Signed-off-by: 's avatarTakashi Sakamoto <o-takashi@sakamocchi.jp>
    Signed-off-by: 's avatarTakashi Iwai <tiwai@suse.de>
fireworks_transaction.c 8.02 KB