Patch "ALSA: hda - Fix deadlock at error in building PCM" has been added to the 4.2-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    ALSA: hda - Fix deadlock at error in building PCM

to the 4.2-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     alsa-hda-fix-deadlock-at-error-in-building-pcm.patch
and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From d289619a219dd01e255d7b5e30f9171b25efea48 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Tue, 20 Oct 2015 16:23:55 +0200
Subject: ALSA: hda - Fix deadlock at error in building PCM

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
@@ -3438,10 +3438,8 @@ int snd_hda_codec_build_pcms(struct hda_
 	int dev, err;
 
 	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) {


Patches currently in stable-queue which might be from tiwai@suse.de are

queue-4.2/alsa-hdac-explicitly-add-io.h.patch
queue-4.2/alsa-hda-fix-deadlock-at-error-in-building-pcm.patch
queue-4.2/alsa-hda-fix-inverted-internal-mic-on-lenovo-g50-80.patch