BUG: unable to handle kernel paging request in drm_fb_helper_damage_work

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 17fbcdf9 Merge tag 'nfsd-5.11-3' of git://git.kernel.org/p..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15ae36f8d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=bd1f72220b2e57eb
dashboard link: https://syzkaller.appspot.com/bug?extid=01c1ae3d62eebced6b29
userspace arch: i386
CC: [b...@alien8.de h...@zytor.com linux-...@vger.kernel.org mi...@redhat.com tg...@linutronix.de x...@kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+01c1ae...@syzkaller.appspotmail.com

BUG: unable to handle page fault for address: ffffc9000cde0fe0
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 10c00067 P4D 10c00067 PUD 10dab067 PMD 1a6d3067 PTE 0
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 3 PID: 30 Comm: kworker/3:0 Not tainted 5.11.0-rc6-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Workqueue: events drm_fb_helper_damage_work
RIP: 0010:rep_movs arch/x86/lib/iomem.c:12 [inline]
RIP: 0010:memcpy_toio+0x83/0xe0 arch/x86/lib/iomem.c:57
Code: 9a fd 49 89 dd 31 ff 41 83 e5 02 4c 89 ee e8 a4 ea 9a fd 4d 85 ed 75 2e e8 aa e2 9a fd 48 89 e9 48 89 df 4c 89 e6 48 c1 e9 02 <f3> a5 40 f6 c5 02 74 02 66 a5 40 f6 c5 01 74 01 a4 5b 5d 41 5c 41
RSP: 0018:ffffc9000057fbc8 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffffc9000cde0fe0 RCX: 0000000000000008
RDX: ffff888011563780 RSI: ffffc9000b101fe0 RDI: ffffc9000cde0fe0
RBP: 0000000000000020 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff83d7eeac R11: 0000000000000000 R12: ffffc9000b101fe0
R13: 0000000000000000 R14: ffffc9000b101fe0 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff88802cd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc9000cde0fe0 CR3: 0000000069890000 CR4: 0000000000150ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
dma_buf_map_memcpy_to include/linux/dma-buf-map.h:245 [inline]
drm_fb_helper_damage_blit_real drivers/gpu/drm/drm_fb_helper.c:388 [inline]
drm_fb_helper_damage_blit drivers/gpu/drm/drm_fb_helper.c:419 [inline]
drm_fb_helper_damage_work+0x733/0xac0 drivers/gpu/drm/drm_fb_helper.c:450
process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
kthread+0x3b1/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Modules linked in:
Dumping ftrace buffer:
(ftrace buffer empty)
CR2: ffffc9000cde0fe0
---[ end trace f43e1e9fbb70527f ]---
RIP: 0010:rep_movs arch/x86/lib/iomem.c:12 [inline]
RIP: 0010:memcpy_toio+0x83/0xe0 arch/x86/lib/iomem.c:57
Code: 9a fd 49 89 dd 31 ff 41 83 e5 02 4c 89 ee e8 a4 ea 9a fd 4d 85 ed 75 2e e8 aa e2 9a fd 48 89 e9 48 89 df 4c 89 e6 48 c1 e9 02 <f3> a5 40 f6 c5 02 74 02 66 a5 40 f6 c5 01 74 01 a4 5b 5d 41 5c 41
RSP: 0018:ffffc9000057fbc8 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffffc9000cde0fe0 RCX: 0000000000000008
RDX: ffff888011563780 RSI: ffffc9000b101fe0 RDI: ffffc9000cde0fe0
RBP: 0000000000000020 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff83d7eeac R11: 0000000000000000 R12: ffffc9000b101fe0
R13: 0000000000000000 R14: ffffc9000b101fe0 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff88802cd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc9000cde0fe0 CR3: 0000000069890000 CR4: 0000000000150ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.