https://bugs.freedesktop.org/show_bug.cgi?id=106456
Bug ID: 106456 Summary: [regression][bisected] Mutex deadlock in nouveau (nv50_display.c) Product: DRI Version: DRI git Hardware: x86-64 (AMD64) OS: Linux (All) Status: NEW Severity: major Priority: medium Component: DRM/other Assignee: dri-devel@lists.freedesktop.org Reporter: john@jlindgren.net
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/?i...
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.