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

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

[Greg Kroah-Hartman]

Description
===========

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
[  512.123323] Call Trace:
[  512.123346]  <TASK>
[  512.123370]  dump_stack_lvl+0x5b/0x77
[  512.123412]  __might_resched.cold+0xff/0x13a
[  512.123458]  ww_mutex_lock+0x1e/0xa0
[  512.123495]  psb_gem_pin+0x2c/0x150 [gma500_gfx]
[  512.123601]  gma_pipe_set_base+0x76/0x240 [gma500_gfx]
[  512.123708]  gma_crtc_page_flip+0x95/0x130 [gma500_gfx]
[  512.123808]  drm_mode_page_flip_ioctl+0x57d/0x5d0
[  512.123897]  ? drm_mode_cursor2_ioctl+0x10/0x10
[  512.123936]  drm_ioctl_kernel+0xa1/0x150
[  512.123984]  drm_ioctl+0x21f/0x420
[  512.124025]  ? drm_mode_cursor2_ioctl+0x10/0x10
[  512.124070]  ? rcu_read_lock_bh_held+0xb/0x60
[  512.124104]  ? lock_release+0x1ef/0x2d0
[  512.124161]  __x64_sys_ioctl+0x8d/0xd0
[  512.124203]  do_syscall_64+0x58/0x80
[  512.124239]  ? do_syscall_64+0x67/0x80
[  512.124267]  ? trace_hardirqs_on_prepare+0x55/0xe0
[  512.124300]  ? do_syscall_64+0x67/0x80
[  512.124340]  ? rcu_read_lock_sched_held+0x10/0x80
[  512.124377]  entry_SYSCALL_64_after_hwframe+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 ORIG_RAX: 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>

The Linux kernel CVE team has assigned CVE-2022-48634 to this issue.


Affected and fixed versions
===========================

	Fixed in 5.10.146 with commit c5812807e416
	Fixed in 5.15.71 with commit e5ae504c8623
	Fixed in 5.19.12 with commit a6ed7624bf4d
	Fixed in 6.0 with commit 63e37a79f7bd

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2022-48634
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/gpu/drm/gma500/gma_display.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/c5812807e416618477d1bb0049727ce8bb8292fd
	https://git.kernel.org/stable/c/e5ae504c8623476e13032670f1a6d6344d53ec9b
	https://git.kernel.org/stable/c/a6ed7624bf4d0a32f2631e74828bca7b7bf15afd
	https://git.kernel.org/stable/c/63e37a79f7bd939314997e29c2f5a9f0ef184281