linux-kernel - null pointer dereference while loading i915

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 08 Aug 2012 06:50:19 +0200
From:	Mihai Moldovan <ionic@...ic.de>
To:	LKML <linux-kernel@...r.kernel.org>
CC:	Daniel Vetter <daniel.vetter@...ll.ch>
Subject: null pointer dereference while loading i915

Hi Daniel, hi list

ever since version 3.2.0 (maybe even earlier, but 3.0.2 is still working fine),
my box is crashing when loading the i915 driver (mode-setting enabled.)

The current version I'm testing with is 3.5.0.

I was able to get the BUG output (please forgive any errors/flips in the output,
I have had to transcribe the messages from the screen/images), however, I'm not
able to find out what's wrong.

If I see it correctly, there's a null pointer dereference in a printk called
from inside gmbus_xfer. The only printk calls I can see in
drivers/gpu/drm/i915/intel_i2c.c gmbus_xfer() however are issued by the
DRM_DEBUG_KMS() and DRM_INFO() macros.
Neither call looks wrong to me, I even tried to swap adapter->name with
bus->adapter.name and make *sure* i < num is true, but haven't had any success.

I'd really like to see this bug fixed, as it's preventing me from updating the
kernel for over a year now.

Also, while 3.0.2 works, it *does* spew error/warning messages related to gmbus
and I've had corrupted VTs in the past (albeit after a long uptime with multiple
X restarting and DVI cable unplugging/reattaching events), so maybe there's a
lot more broken than "expected".

PCI-IDs:

00:02.0 VGA compatible controller [0300]: Intel Corporation 4 Series Chipset
Integrated Graphics Controller [8086:2e12] (rev 03) (prog-if 00 [VGA controller])
    Subsystem: Intel Corporation Device [8086:1003]
00:02.1 Display controller [0380]: Intel Corporation 4 Series Chipset Integrated
Graphics Controller [8086:2e13] (rev 03)
    Subsystem: Intel Corporation Device [8086:1003]

Messages are attached.

Any help is appreciated, thanks. :)

Best regards,

Mihai

Download attachment "i915_kernel_BUG_gmbus_nullptrderef.txt.bz2" of type "application/x-bzip2" (1366 bytes)

Download attachment "i915_3.0.2_warning_messages.txt.bz2" of type "application/x-bzip2" (1141 bytes)

Download attachment "smime.p7s" of type "application/pkcs7-signature" (4506 bytes)