Bug 46274 - Reading from /sys/kernel/debug/dri/0/radeon_ring_cp* cause null-pointer dereference
Summary: Reading from /sys/kernel/debug/dri/0/radeon_ring_cp* cause null-pointer deref...
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Radeon (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium normal
Assignee: Default DRI bug account
QA Contact:
Depends on:
Reported: 2012-02-19 01:33 UTC by Thomas Lindroth
Modified: 2012-02-28 00:03 UTC (History)
0 users

See Also:
i915 platform:
i915 features:

Only create additional ring info files on Cayman or newer (768 bytes, patch)
2012-02-20 09:24 UTC, Michel Dänzer
no flags Details | Splinter Review

Description Thomas Lindroth 2012-02-19 01:33:00 UTC
Using evergreen(cedar) hardware reading from /sys/kernel/debug/dri/0/radeon_ring_cp[12] cause null-pointer dereference with latest linus git(3.3-rc4).
Comment 1 Michel Dänzer 2012-02-20 09:24:58 UTC
Created attachment 57337 [details] [review]
Only create additional ring info files on Cayman or newer

This patch should not create the additional files at all for your card. I've only been able to compile-test it, does it work for you?
Comment 2 Michel Dänzer 2012-02-22 01:55:59 UTC
I've tested the fix and submitted it, should make it into 3.3 final.
Comment 3 Florian Mickler 2012-02-27 14:29:59 UTC
A patch referencing this bug report has been merged in Linux v3.3-rc5:

commit f0d14daa6906070ca044b86f483fdde7d81f5294
Author: Michel Dänzer <michel.daenzer@amd.com>
Date:   Tue Feb 21 17:39:15 2012 +0100

    drm/radeon: Only create additional ring debugfs files on Cayman or newer.
Comment 4 Michel Dänzer 2012-02-28 00:03:24 UTC
Resolving per comment #3.

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