CVE-2022-48634

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

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

gmacrtcpageflip() was holding the eventlock spinlock while calling crtcfuncs->modesetbase() which takes wwmutex.

The only reason to hold eventlock is to clear gmacrtc->pageflipevent on modesetbase() errors.

Instead unlock it after setting gmacrtc->pageflipevent and on errors re-take the lock and clear gmacrtc->pageflipevent 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] inatomic(): 1, irqsdisabled(): 1, nonblock: 0, pid: 1253, name: gnome-shell [ 512.123031] preemptcount: 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>] copyprocess+0x9fc/0x1de0 [ 512.123176] softirqs last enabled at (0): [<ffffffff8d0ec28c>] copyprocess+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/SJE01CT, BIOS V1.10 07/23/2013 [ 512.123323] Call Trace: [ 512.123346] <TASK> [ 512.123370] dumpstack_lvl+0x5b/0x77 [ 512.123412] __mightresched.cold+0xff/0x13a [ 512.123458] wwmutexlock+0x1e/0xa0 [ 512.123495] psbgempin+0x2c/0x150 [gma500gfx] [ 512.123601] gmapipesetbase+0x76/0x240 [gma500gfx] [ 512.123708] gmacrtcpageflip+0x95/0x130 [gma500gfx] [ 512.123808] drmmodepageflipioctl+0x57d/0x5d0 [ 512.123897] ? drmmodecursor2ioctl+0x10/0x10 [ 512.123936] drmioctlkernel+0xa1/0x150 [ 512.123984] drmioctl+0x21f/0x420 [ 512.124025] ? drmmodecursor2ioctl+0x10/0x10 [ 512.124070] ? rcureadlockbhheld+0xb/0x60 [ 512.124104] ? lockrelease+0x1ef/0x2d0 [ 512.124161] __x64sysioctl+0x8d/0xd0 [ 512.124203] dosyscall64+0x58/0x80 [ 512.124239] ? dosyscall64+0x67/0x80 [ 512.124267] ? tracehardirqsonprepare+0x55/0xe0 [ 512.124300] ? dosyscall64+0x67/0x80 [ 512.124340] ? rcureadlockschedheld+0x10/0x80 [ 512.124377] entrySYSCALL64afterhwframe+0x63/0xcd [ 512.124411] RIP: 0033:0x7fcc4a70740f [ 512.124442] Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 18 48 8b 44 24 18 64 48 2b 04 25 28 00 00 [ 512.124470] RSP: 002b:00007ffda73f5390 EFLAGS: 00000246 ORIGRAX: 0000000000000010 [ 512.124503] RAX: ffffffffffffffda RBX: 000055cc9e474500 RCX: 00007fcc4a70740f [ 512.124524] RDX: 00007ffda73f5420 RSI: 00000000c01864b0 RDI: 0000000000000009 [ 512.124544] RBP: 00007ffda73f5420 R08: 000055cc9c0b0cb0 R09: 0000000000000034 [ 512.124564] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000c01864b0 [ 512.124584] R13: 0000000000000009 R14: 000055cc9df484d0 R15: 000055cc9af5d0c0 [ 512.124647] </TASK>