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[17/78] ALSA: HDA: Fix Oops caused by dereference NULL pointer

Message ID 1369776027-17859-18-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa May 28, 2013, 9:19 p.m. UTC 
3.8.13.1 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Wang YanQing <udknight@gmail.com>

commit 2195b063f6609e4c6268f291683902f25eaf9aa6 upstream.

The interrupt handler azx_interrupt will call azx_update_rirb,
which may call snd_hda_queue_unsol_event, snd_hda_queue_unsol_event
will dereference chip->bus pointer.

The problem is we alloc chip->bus in azx_codec_create
which will be called after we enable IRQ and enable unsolicited
event in azx_probe.

This will cause Oops due dereference NULL pointer. I meet it, good luck:)

[Rearranged the NULL check before the tracepoint and added another
 NULL check of bus->workq -- tiwai]

Signed-off-by: Wang YanQing <udknight@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 sound/pci/hda/hda_codec.c | 3 +++
 1 file changed, 3 insertions(+)
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Patch

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index 622f726..f283157 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -617,6 +617,9 @@  int snd_hda_queue_unsol_event(struct hda_bus *bus, u32 res, u32 res_ex)
 	struct hda_bus_unsolicited *unsol;
 	unsigned int wp;
 
+	if (!bus || !bus->workq)
+		return 0;
+
 	trace_hda_unsol_event(bus, res, res_ex);
 	unsol = bus->unsol;
 	if (!unsol)