| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.13 47/85] ALSA: hda: Abort capability probe at invalid register read | Date | Tue, 24 Oct 2017 15:07:21 +0200 |
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4.13-stable review patch. If anyone has any objections, please let me know.
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From: Takashi Iwai <tiwai@suse.de>
commit 098a0a62c1554f5a3813ef1b8539563214ada8f6 upstream.
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") Acked-by: Vinod Koul <vinod.koul@intel.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- sound/hda/hdac_controller.c | 5 +++++ 1 file changed, 5 insertions(+)
--- a/sound/hda/hdac_controller.c +++ b/sound/hda/hdac_controller.c @@ -284,6 +284,11 @@ int snd_hdac_bus_parse_capabilities(stru 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");
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