Hello, syzbot found the following issue on: HEAD commit: ac347a0655db Merge tag 'arm64-fixes' of git://git.kernel.o.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=101ba588e80000 kernel config: https://syzkaller.appspot.com/x/.config?x=88e7ba51eecd9cd6 dashboard link: https://syzkaller.appspot.com/bug?extid=2e93e6fb36e6fdc56574 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=11252f97680000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10fd2498e80000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/8fcb90d89768/disk-ac347a06.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/360d9341a71c/vmlinux-ac347a06.xz kernel image: https://storage.googleapis.com/syzbot-assets/a370aa406c63/bzImage-ac347a06.xz The issue was bisected to: commit ea40d7857d5250e5400f38c69ef9e17321e9c4a2 Author: Daniel Vetter <daniel.vetter@xxxxxxxx> Date: Fri Oct 9 23:21:56 2020 +0000 drm/vkms: fbdev emulation support bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1058223f680000 final oops: https://syzkaller.appspot.com/x/report.txt?x=1258223f680000 console output: https://syzkaller.appspot.com/x/log.txt?x=1458223f680000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+2e93e6fb36e6fdc56574@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: ea40d7857d52 ("drm/vkms: fbdev emulation support") divide error: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 5068 Comm: syz-executor357 Not tainted 6.6.0-syzkaller-16039-gac347a0655db #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023 RIP: 0010:drm_mode_vrefresh drivers/gpu/drm/drm_modes.c:1303 [inline] RIP: 0010:drm_mode_debug_printmodeline+0x118/0x4e0 drivers/gpu/drm/drm_modes.c:60 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 fb 07 66 fc eb 05 e8 f4 07 66 fc 48 89 RSP: 0018:ffffc9000391f8d0 EFLAGS: 00010246 RAX: 000000000001f400 RBX: ffff888025045000 RCX: 000000000001f400 RDX: 0000000000000000 RSI: 0000000000008000 RDI: ffff888025045018 RBP: 0000000000000000 R08: ffffffff8528b9af R09: 0000000000000000 R10: ffffc9000391f8a0 R11: fffff52000723f17 R12: 0000000000000080 R13: dffffc0000000000 R14: 0000000000000080 R15: ffff888025045016 FS: 0000555556932380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000005fdeb8 CR3: 000000007fcff000 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+0x362/0x500 drivers/gpu/drm/drm_ioctl.c:792 drm_ioctl+0x636/0xb00 drivers/gpu/drm/drm_ioctl.c:895 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:51 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f6c63dd6729 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:00007ffcde0dd0e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffcde0dd2b8 RCX: 00007f6c63dd6729 RDX: 0000000020000180 RSI: 00000000c06864a2 RDI: 0000000000000003 RBP: 00007f6c63e49610 R08: 00000000fffff4e6 R09: 00007ffcde0dd2b8 R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffcde0dd2a8 R14: 0000000000000001 R15: 0000000000000001 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:drm_mode_vrefresh drivers/gpu/drm/drm_modes.c:1303 [inline] RIP: 0010:drm_mode_debug_printmodeline+0x118/0x4e0 drivers/gpu/drm/drm_modes.c:60 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 fb 07 66 fc eb 05 e8 f4 07 66 fc 48 89 RSP: 0018:ffffc9000391f8d0 EFLAGS: 00010246 RAX: 000000000001f400 RBX: ffff888025045000 RCX: 000000000001f400 RDX: 0000000000000000 RSI: 0000000000008000 RDI: ffff888025045018 RBP: 0000000000000000 R08: ffffffff8528b9af R09: 0000000000000000 R10: ffffc9000391f8a0 R11: fffff52000723f17 R12: 0000000000000080 R13: dffffc0000000000 R14: 0000000000000080 R15: ffff888025045016 FS: 0000555556932380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000064392c CR3: 000000007fcff000 CR4: 00000000003506f0 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 fb 07 66 fc call 0xfc660832 37: eb 05 jmp 0x3e 39: e8 f4 07 66 fc call 0xfc660832 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 syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection If the report is already addressed, 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 report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
