[PATCH 4.1 20/86] ALSA: hda - Fix deadlock at error in building PCM

Greg Kroah-Hartman
2015-11-06T20:24:03Z

From: Takashi Iwai <tiwai@suse.de>

commit d289619a219dd01e255d7b5e30f9171b25efea48 upstream.

The HDA codec driver issues snd_hda_codec_reset() at the error path of
PCM build. This was needed in the earlier code base, but the recent
rewrite to use the standard bus binding made this a deadlock:
modprobe D 0000000000000005 0 720 716 0x00000080
Call Trace:
[<ffffffff816a5dbe>] schedule+0x3e/0x90
[<ffffffff816a61a5>] schedule_preempt_disabled+0x15/0x20
[<ffffffff816a7ae5>] __mutex_lock_slowpath+0xb5/0x120
[<ffffffff816a7b6b>] mutex_lock+0x1b/0x30
[<ffffffff8148656b>] device_release_driver+0x1b/0x30
[<ffffffff81485c15>] bus_remove_device+0x105/0x180
[<ffffffff814822b9>] device_del+0x139/0x260
[<ffffffffa05e0ec5>] snd_hdac_device_unregister+0x25/0x30 [snd_hda_core]
[<ffffffffa074fa6a>] snd_hda_codec_reset+0x2a/0x70 [snd_hda_codec]
[<ffffffffa075007b>] snd_hda_codec_build_pcms+0x18b/0x1b0 [snd_hda_codec]
[<ffffffffa074a44e>] hda_codec_driver_probe+0xbe/0x140 [snd_hda_codec]
[<ffffffff81486ac4>] driver_probe_device+0x1f4/0x460
[<ffffffff81486dc0>] __driver_attach+0x90/0xa0
[<ffffffff81484844>] bus_for_each_dev+0x64/0xa0
[<ffffffff814862de>] driver_attach+0x1e/0x20
[<ffffffff81485e7b>] bus_add_driver+0x1eb/0x280
[<ffffffff81487680>] driver_register+0x60/0xe0
[<ffffffffa074a0da>] __hda_codec_driver_register+0x5a/0x60 [snd_hda_codec]
[<ffffffffa070a01e>] realtek_driver_init+0x1e/0x1000 [snd_hda_codec_realtek]
[<ffffffff810002f3>] do_one_initcall+0xb3/0x200
[<ffffffff816a1fc5>] do_init_module+0x60/0x1f8
[<ffffffff810ee5c3>] load_module+0x1653/0x1bd0
[<ffffffff810eed48>] SYSC_finit_module+0x98/0xc0
[<ffffffff810eed8e>] SyS_finit_module+0xe/0x10
[<ffffffff816aa032>] entry_SYSCALL_64_fastpath+0x16/0x75

The simple fix is just to remove this call, since we don't need to
think about unbinding at there any longer.

Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=948758
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
sound/pci/hda/hda_codec.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -3833,10 +3833,8 @@ int snd_hda_codec_build_pcms(struct hda_
return -EINVAL;

err = snd_hda_codec_parse_pcms(codec);
- if (err < 0) {
- snd_hda_codec_reset(codec);
+ if (err < 0)
return err;
- }

/* attach a new PCM streams */
list_for_each_entry(cpcm, &codec->pcm_list_head, list) {