CVE-2022-48634 — drm/gma500: Fix BUG: sleeping function called from invalid context errors

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

drm/gma500: Fix BUG: sleeping function called from invalid context errors

gma_crtc_page_flip() was holding the event_lock spinlock while calling crtc_funcs->mode_set_base() which takes ww_mutex.

The only reason to hold event_lock is to clear gma_crtc->page_flip_event on mode_set_base() errors.

Instead unlock it after setting gma_crtc->page_flip_event and on errors re-take the lock and clear gma_crtc->page_flip_event it it is still set.

This fixes the following WARN/stacktrace:

[ 512.122953] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:870 [ 512.123004] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 1253, name: gnome-shell [ 512.123031] preempt_count: 1, expected: 0 [ 512.123048] RCU nest depth: 0, expected: 0 [ 512.123066] INFO: lockdep is turned off. [ 512.123080] irq event stamp: 0 [ 512.123094] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [ 512.123134] hardirqs last disabled at (0): [<ffffffff8d0ec28c>] copy_process+0x9fc/0x1de0 [ 512.123176] softirqs last enabled at (0): [<ffffffff8d0ec28c>] copy_process+0x9fc/0x1de0 [ 512.123207] softirqs last disabled at (0): [<0000000000000000>] 0x0 [ 512.123233] Preemption disabled at: [ 512.123241] [<0000000000000000>] 0x0 [ 512.123275] CPU: 3 PID: 1253 Comm: gnome-shell Tainted: G W 5.19.0+ #1 [ 512.123304] Hardware name: Packard Bell dot s/SJE01_CT, BIOS V1.10 07/23/2013 [ 512.…

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CVE-2022-48634 — drm/gma500: Fix BUG: sleeping function called from invalid context errors