[v6.1] divide error in drm_mode_debug_printmodeline

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 09045dae0d90 Linux 6.1.53
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13afdcac680000
kernel config: https://syzkaller.appspot.com/x/.config?x=195b6ef285251409
dashboard link: https://syzkaller.appspot.com/bug?extid=ea0ff9cfb920e6638412
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=152f4264680000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12db0274680000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c3b1bb820e74/disk-09045dae.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4c5cfb0563d9/vmlinux-09045dae.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c682edb60d96/bzImage-09045dae.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ea0ff9...@syzkaller.appspotmail.com

divide error: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 3542 Comm: syz-executor350 Not tainted 6.1.53-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023
RIP: 0010:drm_mode_vrefresh drivers/gpu/drm/drm_modes.c:826 [inline]
RIP: 0010:drm_mode_debug_printmodeline+0x114/0x4e0 drivers/gpu/drm/drm_modes.c:59
Code: 00 41 0f b7 07 66 83 f8 02 b9 01 00 00 00 0f 43 c8 0f b7 c1 0f af e8 44 89 f0 48 69 c8 e8 03 00 00 89 e8 d1 e8 48 01 c8 31 d2 <48> f7 f5 49 89 c6 eb 0c e8 af a0 cb fc eb 05 e8 a8 a0 cb fc 48 89
RSP: 0018:ffffc900039df8f0 EFLAGS: 00010246
RAX: 000000000001f400 RBX: ffff888022a3ec00 RCX: 000000000001f400
RDX: 0000000000000000 RSI: 0000000000008000 RDI: ffff888022a3ec18
RBP: 0000000000000000 R08: ffffffff84be72db R09: ffffc900039df8c0
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000080
R13: dffffc0000000000 R14: 0000000000000080 R15: ffff888022a3ec16
FS: 0000555557523380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000080 CR3: 0000000072740000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
drm_mode_setcrtc+0x837/0x1870 drivers/gpu/drm/drm_crtc.c:794
drm_ioctl_kernel+0x345/0x4f0 drivers/gpu/drm/drm_ioctl.c:788
drm_ioctl+0x618/0x9f0 drivers/gpu/drm/drm_ioctl.c:891
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f7670638729
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdec685298 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffdec685468 RCX: 00007f7670638729
RDX: 0000000020000180 RSI: 00000000c06864a2 RDI: 0000000000000003
RBP: 00007f76706ab610 R08: 00000000fffff4e6 R09: 00007ffdec685468
R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffdec685458 R14: 0000000000000001 R15: 0000000000000001
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:drm_mode_vrefresh drivers/gpu/drm/drm_modes.c:826 [inline]
RIP: 0010:drm_mode_debug_printmodeline+0x114/0x4e0 drivers/gpu/drm/drm_modes.c:59
Code: 00 41 0f b7 07 66 83 f8 02 b9 01 00 00 00 0f 43 c8 0f b7 c1 0f af e8 44 89 f0 48 69 c8 e8 03 00 00 89 e8 d1 e8 48 01 c8 31 d2 <48> f7 f5 49 89 c6 eb 0c e8 af a0 cb fc eb 05 e8 a8 a0 cb fc 48 89
RSP: 0018:ffffc900039df8f0 EFLAGS: 00010246
RAX: 000000000001f400 RBX: ffff888022a3ec00 RCX: 000000000001f400
RDX: 0000000000000000 RSI: 0000000000008000 RDI: ffff888022a3ec18
RBP: 0000000000000000 R08: ffffffff84be72db R09: ffffc900039df8c0
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000080
R13: dffffc0000000000 R14: 0000000000000080 R15: ffff888022a3ec16
FS: 0000555557523380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000080 CR3: 0000000072740000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 00 41 0f add %al,0xf(%rcx)
3: b7 07 mov $0x7,%bh
5: 66 83 f8 02 cmp $0x2,%ax
9: b9 01 00 00 00 mov $0x1,%ecx
e: 0f 43 c8 cmovae %eax,%ecx
11: 0f b7 c1 movzwl %cx,%eax
14: 0f af e8 imul %eax,%ebp
17: 44 89 f0 mov %r14d,%eax
1a: 48 69 c8 e8 03 00 00 imul $0x3e8,%rax,%rcx
21: 89 e8 mov %ebp,%eax
23: d1 e8 shr %eax
25: 48 01 c8 add %rcx,%rax
28: 31 d2 xor %edx,%edx
* 2a: 48 f7 f5 div %rbp <-- trapping instruction
2d: 49 89 c6 mov %rax,%r14
30: eb 0c jmp 0x3e
32: e8 af a0 cb fc call 0xfccba0e6
37: eb 05 jmp 0x3e
39: e8 a8 a0 cb fc call 0xfccba0e6
3e: 48 rex.W
3f: 89 .byte 0x89


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup