[alsa-devel] [PATCH]ALSA: HDA: Fix Oops caused by dereference NULL pointer
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:)
Signed-off-by: Wang YanQing udknight@gmail.com --- 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 622f726..9c76752 100644 --- a/sound/pci/hda/hda_codec.c +++ b/sound/pci/hda/hda_codec.c @@ -618,6 +618,9 @@ int snd_hda_queue_unsol_event(struct hda_bus *bus, u32 res, u32 res_ex) unsigned int wp;
trace_hda_unsol_event(bus, res, res_ex); + if (!bus) + return 0; + unsol = bus->unsol; if (!unsol) return 0;
At Tue, 7 May 2013 11:27:33 +0800, Wang YanQing wrote:
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:)
Signed-off-by: Wang YanQing udknight@gmail.com
Thanks, applied with a slight fix (put before the tracepoint so that it won't give more NULL dereference, and also put another NULL check of bus->workq as done in hda_intel.c.)
Takashi
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 622f726..9c76752 100644 --- a/sound/pci/hda/hda_codec.c +++ b/sound/pci/hda/hda_codec.c @@ -618,6 +618,9 @@ int snd_hda_queue_unsol_event(struct hda_bus *bus, u32 res, u32 res_ex) unsigned int wp;
trace_hda_unsol_event(bus, res, res_ex);
- if (!bus)
return 0;- unsol = bus->unsol; if (!unsol) return 0;
-- 1.7.12.4.dirty
participants (2)
-
Takashi Iwai -
Wang YanQing