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Subject[syzbot] BUG: unable to handle kernel paging request in drm_fb_helper_damage_work (3)
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Hello,

syzbot found the following issue on:

HEAD commit: 5833291ab6de Merge tag 'pci-v5.16-fixes-1' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11d04e6eb00000
kernel config: https://syzkaller.appspot.com/x/.config?x=9d7259f0deb293aa
dashboard link: https://syzkaller.appspot.com/bug?extid=38cf2d663fcac29c9e0b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: i386

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+38cf2d663fcac29c9e0b@syzkaller.appspotmail.com

BUG: unable to handle page fault for address: ffffc900048f1000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 10c00067 P4D 10c00067 PUD 10dbe067 PMD 45f19067 PTE 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 3 PID: 4467 Comm: kworker/3:6 Not tainted 5.15.0-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: 83 fd 49 89 dd 31 ff 41 83 e5 02 4c 89 ee e8 f4 22 83 fd 4d 85 ed 75 2e e8 5a 20 83 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:ffffc90006d9fbc8 EFLAGS: 00010206
RAX: 0000000000000000 RBX: ffffc900066fd000 RCX: 0000000000000400
RDX: ffff88801b369d00 RSI: ffffc900048f1000 RDI: ffffc90006700000
RBP: 0000000000004000 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff83f4a60c R11: 0000000000000000 R12: ffffc900048ee000
R13: 0000000000000000 R14: ffffc900048ee000 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff88802cd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc900048f1000 CR3: 0000000071bde000 CR4: 0000000000150ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
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+0x9b2/0x1690 kernel/workqueue.c:2298
worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Modules linked in:
CR2: ffffc900048f1000
---[ end trace 3c61e5e2b34760bf ]---
RIP: 0010:rep_movs arch/x86/lib/iomem.c:12 [inline]
RIP: 0010:memcpy_toio+0x83/0xe0 arch/x86/lib/iomem.c:57
Code: 83 fd 49 89 dd 31 ff 41 83 e5 02 4c 89 ee e8 f4 22 83 fd 4d 85 ed 75 2e e8 5a 20 83 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:ffffc90006d9fbc8 EFLAGS: 00010206
RAX: 0000000000000000 RBX: ffffc900066fd000 RCX: 0000000000000400
RDX: ffff88801b369d00 RSI: ffffc900048f1000 RDI: ffffc90006700000
RBP: 0000000000004000 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff83f4a60c R11: 0000000000000000 R12: ffffc900048ee000
R13: 0000000000000000 R14: ffffc900048ee000 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff88802cd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc900048f1000 CR3: 0000000071bde000 CR4: 0000000000150ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 83 fd 49 cmp $0x49,%ebp
3: 89 dd mov %ebx,%ebp
5: 31 ff xor %edi,%edi
7: 41 83 e5 02 and $0x2,%r13d
b: 4c 89 ee mov %r13,%rsi
e: e8 f4 22 83 fd callq 0xfd832307
13: 4d 85 ed test %r13,%r13
16: 75 2e jne 0x46
18: e8 5a 20 83 fd callq 0xfd832077
1d: 48 89 e9 mov %rbp,%rcx
20: 48 89 df mov %rbx,%rdi
23: 4c 89 e6 mov %r12,%rsi
26: 48 c1 e9 02 shr $0x2,%rcx
* 2a: f3 a5 rep movsl %ds:(%rsi),%es:(%rdi) <-- trapping instruction
2c: 40 f6 c5 02 test $0x2,%bpl
30: 74 02 je 0x34
32: 66 a5 movsw %ds:(%rsi),%es:(%rdi)
34: 40 f6 c5 01 test $0x1,%bpl
38: 74 01 je 0x3b
3a: a4 movsb %ds:(%rsi),%es:(%rdi)
3b: 5b pop %rbx
3c: 5d pop %rbp
3d: 41 5c pop %r12
3f: 41 rex.B


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

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