Bug 36744 - [NVA5] BUG: unable to handle kernel NULL pointer dereference
Summary: [NVA5] BUG: unable to handle kernel NULL pointer dereference
Status: RESOLVED FIXED
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/nouveau (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium normal
Assignee: Nouveau Project
QA Contact: Xorg Project Team
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2011-05-01 09:07 UTC by Patrice Mandin
Modified: 2011-05-25 01:54 UTC (History)
0 users

See Also:
i915 platform:
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Attachments
Kernel log (34.49 KB, text/plain)
2011-05-01 09:07 UTC, Patrice Mandin 		no flags Details
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Description Patrice Mandin 2011-05-01 09:07:17 UTC 
Created attachment 46222 [details]
Kernel log

Since commit e5ca5dec3111772ade1cbbead50c0c594a49778d (bisected, drm/nouveau: remove remnants of nouveau_pgraph_engine) to nouveau/linux-2.6, I get NULL pointer dereference when starting kernel.
Comment 1 Patrice Mandin 2011-05-06 13:08:25 UTC 
Booting kernel without 'nouveau.noaccel=1' makes it work. So it appears the noaccel case has been broken by said git commit.
Comment 2 Patrice Mandin 2011-05-23 02:11:14 UTC 
In nouveau_card_init() function (nouveau_state.c file), engine->fifo.init() function is not called when nouveau_noaccel is enabled.

On NV50/NVA0 cards, engine->fifo.init = nv50_fifo_init (nv50_fifo.c file) and this function is responsible to fill pfifo->playlist array, which is not done with nouveau_noaccel enabled.

When nv50_fifo_playlist_update() is called, accessing pfifo->playlist (which was not initialized) triggers the NULL pointer dereference.
Comment 3 Patrice Mandin 2011-05-25 01:54:45 UTC 
Fixed in git nouveau/linux-2.6 repository. Thanks darktama.

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