[05/65] ALSA: HDA: Fix Oops caused by dereference NULL pointer

Steven Rostedt
2013-06-03T22:25:13Z

[-- Attachment #1: 0005-ALSA-HDA-Fix-Oops-caused-by-dereference-NULL-pointer.patch --]
[-- Type: text/plain, Size: 1387 bytes --]

3.6.11.5 stable review patch.
If anyone has any objections, please let me know.

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

From: Wang YanQing <udknight@gmail.com>

[ Upstream commit 2195b063f6609e4c6268f291683902f25eaf9aa6 ]

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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
sound/pci/hda/hda_codec.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index 558b6b0..693e890 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -609,6 +609,9 @@ 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)
--
1.7.10.4