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Message-ID: <000000000000cb628c060a664eb0@google.com>
Date: Fri, 17 Nov 2023 21:13:04 -0800
From: syzbot <syzbot+2e93e6fb36e6fdc56574@...kaller.appspotmail.com>
To: eadavis@...com, linux-kernel@...r.kernel.org,
syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [dri?] divide error in drm_mode_debug_printmodeline
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
divide error in drm_mode_debug_printmodeline
mode: ffff888140bc9490, ht: 1344, vt: 806, c: 65000, vsc: 0, den: 1083264, num: 65000, drm_mode_vrefresh
mode: ffff88807c374000, ht: 128, vt: 32768, c: 128, vsc: 1024, den: 4294967296, num: 128, drm_mode_vrefresh
divide error: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 5448 Comm: syz-executor.0 Not tainted 6.6.0-rc7-syzkaller-00142-g888cf78c29e2-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
RIP: 0010:drm_mode_vrefresh drivers/gpu/drm/drm_modes.c:1305 [inline]
RIP: 0010:drm_mode_debug_printmodeline+0x308/0x5d0 drivers/gpu/drm/drm_modes.c:60
Code: b4 8c 4c 8b 7c 24 30 41 57 55 e8 53 c9 e7 05 48 83 c4 18 44 89 f8 48 69 c8 e8 03 00 00 48 89 e8 48 d1 e8 48 01 c8 89 e9 31 d2 <48> f7 f1 49 89 c0 e9 81 fd ff ff 89 e9 80 e1 07 fe c1 38 c1 0f 8c
RSP: 0018:ffffc90004e1f8d0 EFLAGS: 00010246
RAX: 000000008001f400 RBX: ffff88807c374000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000100000000 R08: ffffffff81711cfc R09: 1ffff920009c3e6c
R10: dffffc0000000000 R11: fffff520009c3e6d R12: dffffc0000000000
R13: 0000000000000080 R14: 1ffff1100f86e801 R15: 0000000000000080
FS: 00007fb08687c6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb085b980c0 CR3: 000000007eb58000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
drm_mode_setcrtc+0x83b/0x1880 drivers/gpu/drm/drm_crtc.c:794
drm_ioctl_kernel+0x349/0x4f0 drivers/gpu/drm/drm_ioctl.c:789
drm_ioctl+0x636/0xb00 drivers/gpu/drm/drm_ioctl.c:892
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xf8/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fb085a7cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb08687c0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fb085b9bf80 RCX: 00007fb085a7cae9
RDX: 0000000020000180 RSI: 00000000c06864a2 RDI: 0000000000000003
RBP: 00007fb085ac847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fb085b9bf80 R15: 00007ffe452acab8
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:drm_mode_vrefresh drivers/gpu/drm/drm_modes.c:1305 [inline]
RIP: 0010:drm_mode_debug_printmodeline+0x308/0x5d0 drivers/gpu/drm/drm_modes.c:60
Code: b4 8c 4c 8b 7c 24 30 41 57 55 e8 53 c9 e7 05 48 83 c4 18 44 89 f8 48 69 c8 e8 03 00 00 48 89 e8 48 d1 e8 48 01 c8 89 e9 31 d2 <48> f7 f1 49 89 c0 e9 81 fd ff ff 89 e9 80 e1 07 fe c1 38 c1 0f 8c
RSP: 0018:ffffc90004e1f8d0 EFLAGS: 00010246
RAX: 000000008001f400 RBX: ffff88807c374000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000100000000 R08: ffffffff81711cfc R09: 1ffff920009c3e6c
R10: dffffc0000000000 R11: fffff520009c3e6d R12: dffffc0000000000
R13: 0000000000000080 R14: 1ffff1100f86e801 R15: 0000000000000080
FS: 00007fb08687c6c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc82ccfc378 CR3: 000000007eb58000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: b4 8c mov $0x8c,%ah
2: 4c 8b 7c 24 30 mov 0x30(%rsp),%r15
7: 41 57 push %r15
9: 55 push %rbp
a: e8 53 c9 e7 05 call 0x5e7c962
f: 48 83 c4 18 add $0x18,%rsp
13: 44 89 f8 mov %r15d,%eax
16: 48 69 c8 e8 03 00 00 imul $0x3e8,%rax,%rcx
1d: 48 89 e8 mov %rbp,%rax
20: 48 d1 e8 shr %rax
23: 48 01 c8 add %rcx,%rax
26: 89 e9 mov %ebp,%ecx
28: 31 d2 xor %edx,%edx
* 2a: 48 f7 f1 div %rcx <-- trapping instruction
2d: 49 89 c0 mov %rax,%r8
30: e9 81 fd ff ff jmp 0xfffffdb6
35: 89 e9 mov %ebp,%ecx
37: 80 e1 07 and $0x7,%cl
3a: fe c1 inc %cl
3c: 38 c1 cmp %al,%cl
3e: 0f .byte 0xf
3f: 8c .byte 0x8c
Tested on:
commit: 888cf78c Merge tag 'iommu-fix-v6.6-rc7' of git://git.k..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=146669b8e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0d47f0e0359e88e
dashboard link: https://syzkaller.appspot.com/bug?extid=2e93e6fb36e6fdc56574
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=10890c77680000
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