1. 12 Jan, 2016 1 commit
    • Takashi Iwai's avatar
      ALSA: usb-audio: Avoid calling usb_autopm_put_interface() at disconnect · 5c06d68b
      Takashi Iwai authored
      ALSA PCM may still have a leftover instance after disconnection and
      it delays its release.  The problem is that the PCM close code path of
      USB-audio driver has a call of snd_usb_autosuspend().  This involves
      with the call of usb_autopm_put_interface() and it may lead to a
      kernel Oops due to the NULL object like:
      
       BUG: unable to handle kernel NULL pointer dereference at 0000000000000190
       IP: [<ffffffff815ae7ef>] usb_autopm_put_interface+0xf/0x30 PGD 0
       Call Trace:
        [<ffffffff8173bd94>] snd_usb_autosuspend+0x14/0x20
        [<ffffffff817461bc>] snd_usb_pcm_close.isra.14+0x5c/0x90
        [<ffffffff8174621f>] snd_usb_playback_close+0xf/0x20
        [<ffffffff816ef58a>] snd_pcm_release_substream.part.36+0x3a/0x90
        [<ffffffff816ef6b3>] snd_pcm_release+0xa3/0xb0
        [<ffffffff816debb0>] snd_disconnect_release+0xd0/0xe0
        [<ffffffff8114d417>] __fput+0x97/0x1d0
        [<ffffffff8114d589>] ____fput+0x9/0x10
        [<ffffffff8109e452>] task_work_run+0x72/0x90
        [<ffffffff81088510>] do_exit+0x280/0xa80
        [<ffffffff8108996a>] do_group_exit+0x3a/0xa0
        [<ffffffff8109261f>] get_signal+0x1df/0x540
        [<ffffffff81040903>] do_signal+0x23/0x620
        [<ffffffff8114c128>] ? do_readv_writev+0x128/0x200
        [<ffffffff810012e1>] prepare_exit_to_usermode+0x91/0xd0
        [<ffffffff810013ba>] syscall_return_slowpath+0x9a/0x120
        [<ffffffff817587cd>] ? __sys_recvmsg+0x5d/0x70
        [<ffffffff810d2765>] ? ktime_get_ts64+0x45/0xe0
        [<ffffffff8115dea0>] ? SyS_poll+0x60/0xf0
        [<ffffffff818d2327>] int_ret_from_sys_call+0x25/0x8f
      
      We have already a check of disconnection in snd_usb_autoresume(), but
      the check is missing its counterpart.  The fix is just to put the same
      check in snd_usb_autosuspend(), too.
      
      Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=109431
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
      5c06d68b
  2. 11 Jan, 2016 22 commits
  3. 10 Jan, 2016 17 commits