Bug 106456

Summary: [regression][bisected] Mutex deadlock in nouveau (nv50_display.c)
Product: DRI Reporter: John Lindgren <john>
Component: DRM/otherAssignee: Default DRI bug account <dri-devel>
Status: RESOLVED FIXED QA Contact:
Severity: major    
Priority: medium    
Version: DRI git   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
Fix mutex deadlock in nouveau driver none

Description John Lindgren 2018-05-09 20:24:29 UTC
Since linux 4.14, the nouveau driver deadlocks at boot.

Downstream report:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1763189?comments=all

The culprit is this commit:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=af2405af07d168e2905f2ac9494d3a804a549f0f

In short, drm_fb_helper_add_one_connector() and drm_fb_helper_remove_one_connector() were incompatibly changed to add locking of a mutex that previously the caller was expected to lock.  The i915 and radeon drivers were updated to no longer lock the mutex, but nouveau was not updated.
Comment 1 John Lindgren 2018-05-09 20:26:24 UTC
Created attachment 139452 [details] [review]
Fix mutex deadlock in nouveau driver
Comment 3 John Lindgren 2018-05-09 23:05:11 UTC
Yes, that looks like the same fix.

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