From: Takashi Iwai <tiwai@suse.de>
To: alsa-devel@alsa-project.org
Cc: Vinod Koul <vinod.koul@intel.com>
Subject: [PATCH] ALSA: hda: Abort capability probe at invalid register read
Date: Tue, 17 Oct 2017 16:47:11 +0200 [thread overview]
Message-ID: <20171017144711.23962-1-tiwai@suse.de> (raw)
The loop in snd_hdac_bus_parse_capabilities() may go to nirvana when
it hits an invalid register value read:
BUG: unable to handle kernel paging request at ffffad5dc41f3fff
IP: pci_azx_readl+0x5/0x10 [snd_hda_intel]
Call Trace:
snd_hdac_bus_parse_capabilities+0x3c/0x1f0 [snd_hda_core]
azx_probe_continue+0x7d5/0x940 [snd_hda_intel]
.....
This happened on a new Intel machine, and we need to check the value
and abort the loop accordingly.
[Note: the fixes tag below indicates only the commit where this patch
can be applied; the original problem was introduced even before that
commit]
Fixes: 6720b38420a0 ("ALSA: hda - move bus_parse_capabilities to core")
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
sound/hda/hdac_controller.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/sound/hda/hdac_controller.c b/sound/hda/hdac_controller.c
index 978dc1801b3a..f6d2985b2520 100644
--- a/sound/hda/hdac_controller.c
+++ b/sound/hda/hdac_controller.c
@@ -284,6 +284,11 @@ int snd_hdac_bus_parse_capabilities(struct hdac_bus *bus)
dev_dbg(bus->dev, "HDA capability ID: 0x%x\n",
(cur_cap & AZX_CAP_HDR_ID_MASK) >> AZX_CAP_HDR_ID_OFF);
+ if (cur_cap == -1) {
+ dev_dbg(bus->dev, "Invalid capability reg read\n");
+ break;
+ }
+
switch ((cur_cap & AZX_CAP_HDR_ID_MASK) >> AZX_CAP_HDR_ID_OFF) {
case AZX_ML_CAP_ID:
dev_dbg(bus->dev, "Found ML capability\n");
--
2.14.2
next reply other threads:[~2017-10-17 14:47 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-17 14:47 Takashi Iwai [this message]
2017-10-17 15:35 ` [PATCH] ALSA: hda: Abort capability probe at invalid register read Ughreja, Rakesh A
2017-10-17 16:16 ` Takashi Iwai
2017-10-18 10:12 ` Ughreja, Rakesh A
2017-10-17 17:15 ` Vinod Koul
2017-10-17 17:15 ` Takashi Iwai
2017-10-18 3:24 ` Vinod Koul
2017-10-18 5:42 ` Takashi Iwai
2017-10-18 10:29 ` Vinod Koul
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