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| author | Takashi Iwai <tiwai@suse.de> | 2016-01-12 13:03:33 (GMT) |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2016-01-12 13:12:38 (GMT) |
| commit | 5c06d68bc2a174a6b82dce9f100f55173b9a5189 (patch) | |
| tree | b9ac126af62c3e8a96fff1ab24fe8ad9e7c5dd2a /sound/usb/card.c | |
| parent | 815ad8623695c7f2aafc216b923b131f1ee12df6 (diff) | |
| download | linux-5c06d68bc2a174a6b82dce9f100f55173b9a5189.tar.xz | |
ALSA: usb-audio: Avoid calling usb_autopm_put_interface() at disconnect
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: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/card.c')
| -rw-r--r-- | sound/usb/card.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/sound/usb/card.c b/sound/usb/card.c index 18f5664..1f09d95 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -675,6 +675,8 @@ int snd_usb_autoresume(struct snd_usb_audio *chip) void snd_usb_autosuspend(struct snd_usb_audio *chip) { + if (atomic_read(&chip->shutdown)) + return; if (atomic_dec_and_test(&chip->active)) usb_autopm_put_interface(chip->pm_intf); } |