Hello, syzbot found the following issue on:
HEAD commit: cc3aa43b44bd Add linux-next specific files for 20251219 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=175fb77c580000 kernel config: https://syzkaller.appspot.com/x/.config?x=f7a09bf3b9133d9d dashboard link: https://syzkaller.appspot.com/bug?extid=c9f3062e1f1e68af836a compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/b1b23d9783ee/disk-cc3aa43b.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/07451939cf74/vmlinux-cc3aa43b.xz kernel image: https://storage.googleapis.com/syzbot-assets/e5ddf385746f/bzImage-cc3aa43b.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: [email protected] ------------[ cut here ]------------ faux_driver vkms: [drm] vblank wait timed out on crtc 0 WARNING: drivers/gpu/drm/drm_vblank.c:1320 at drm_crtc_wait_one_vblank+0x33a/0x4f0 drivers/gpu/drm/drm_vblank.c:1320, CPU#1: kworker/1:2/19751 Modules linked in: CPU: 1 UID: 0 PID: 19751 Comm: kworker/1:2 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: events drm_fb_helper_damage_work RIP: 0010:drm_crtc_wait_one_vblank+0x4a3/0x4f0 drivers/gpu/drm/drm_vblank.c:1320 Code: 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 4c 89 ef e8 ff ee e1 fc 4d 8b 7d 00 4c 89 e7 48 8b 74 24 18 4c 89 fa 44 89 f1 <67> 48 0f b9 3a 48 8b 7c 24 28 44 89 f6 e8 8b f6 ff ff b8 92 ff ff RSP: 0018:ffffc9000bc1f840 EFLAGS: 00010246 RAX: 1ffff11004a3da00 RBX: 1ffff92001783f10 RCX: 0000000000000000 RDX: ffffffff8c08f7a0 RSI: ffffffff8c0aa5c0 RDI: ffffffff8fced610 RBP: ffffc9000bc1f948 R08: ffffffff8fc3d077 R09: 1ffffffff1f87a0e R10: dffffc0000000000 R11: fffffbfff1f87a0f R12: ffffffff8fced610 R13: ffff8880251ed000 R14: 0000000000000000 R15: ffffffff8c08f7a0 FS: 0000000000000000(0000) GS:ffff888125adc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005627ed0d9b20 CR3: 000000002e21a000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: <TASK> drm_client_modeset_wait_for_vblank+0xc5/0xf0 drivers/gpu/drm/drm_client_modeset.c:1330 drm_fb_helper_fb_dirty drivers/gpu/drm/drm_fb_helper.c:236 [inline] drm_fb_helper_damage_work+0xc9/0x710 drivers/gpu/drm/drm_fb_helper.c:271 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 </TASK> ---------------- Code disassembly (best guess): 0: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx 7: fc ff df a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) e: 74 08 je 0x18 10: 4c 89 ef mov %r13,%rdi 13: e8 ff ee e1 fc call 0xfce1ef17 18: 4d 8b 7d 00 mov 0x0(%r13),%r15 1c: 4c 89 e7 mov %r12,%rdi 1f: 48 8b 74 24 18 mov 0x18(%rsp),%rsi 24: 4c 89 fa mov %r15,%rdx 27: 44 89 f1 mov %r14d,%ecx * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: 48 8b 7c 24 28 mov 0x28(%rsp),%rdi 34: 44 89 f6 mov %r14d,%esi 37: e8 8b f6 ff ff call 0xfffff6c7 3c: b8 .byte 0xb8 3d: 92 xchg %eax,%edx 3e: ff (bad) 3f: ff .byte 0xff --- 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 [email protected]. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title 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
