From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f77.google.com (mail-ot1-f77.google.com [209.85.210.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 98BD01A275 for ; Thu, 25 Dec 2025 00:33:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766622800; cv=none; b=ZXblnv21kEFyfIIR/oeBfdHLUCq0EV6ycxVP/ncVVefyjrFZKJS0GMOcO4lgW+w1kLlzsfP2qjjFDroevENDoDxuKlaIIwViRtTJJa5i3j+FNxZiBP7UvzZfcfXfAGxZ1Gvq7ghb33+iFid12hr0rxS87d8OVbOpdoKCeh7vuSk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766622800; c=relaxed/simple; bh=y3bbC9gQ9DDpqJQRtCo4xtEY0NRspFuz6+pP5gmqq/k=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=QqY9Ylu6FpL2jVW4RYK+z8bw5MmFx6BXgiR/2Ldoy52X2ouHC5xXfbEYyMDe4gHh21JIhbDDullPQJT04acnfFVDjnduLpdtObNiYj7jvz3EHgGmomk+qao5NvtiKpkVAWJqMiwY8q4cqQQu0DeKAI5TYB2a8syGREMeVWwoOFE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.210.77 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-ot1-f77.google.com with SMTP id 46e09a7af769-7cad1393ec8so13127042a34.0 for ; Wed, 24 Dec 2025 16:33:18 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1766622797; x=1767227597; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=5uhpoHrh3BvVX/j1akM/WBbeEEdFzi5EXt/jkxmHEMY=; b=CGzpO8WJi1fIyndSBMm1Bi1Qek0QXJJKcMnFT8IlW9smg48s+zJEwmnrMSl3rMMnf2 bk6ohkRxGdIln86eEc/sqHxiUmFVO3W0WzGBM1EVK+f+WqbSp6tloD2KmKbKqxAa6JqX uUQuCCy4NGp5TR9hKDZxwmmEQA0ZsZLMraCv45GIqvqiIHrGq/1szQrl0TVJi2SYTx4r C8d3jngtqd+iGlWk+zu2wCYDfAfSoKApnqhpL8hRXKrqg3j63awQh+GFaaayefmazbVZ kWFUrKUGKrSrRpPYXoF012wH5qRWjVC98yDOHDwI8h12X7joUKE2QgZ1jEWLm+aEPign gu5g== X-Forwarded-Encrypted: i=1; AJvYcCUC3Xg0LYqQ1LBOf16v5uCitIBLE//ggkPeXd+LSCoTGXiemwbFgT2cXDunxoD2WzzmKvAMgh49W9xJemo=@vger.kernel.org X-Gm-Message-State: AOJu0Yxdf5GVr5jceWW0bU0YB6QW086demJLWZpLY153xtIBYd0oLNk7 lSY+UEwwKdeDzm/3O4UeUna/ap92HvU8S13sqlAOoDh82LvC7w1jMRZqs/S7+BKpZATMPKarkkp 2mksnrXGTxWlEAT23ScVKUgCHwQYG2/JRs5ujcqrokBhHYYBv80rCR/sYgqQ= X-Google-Smtp-Source: AGHT+IE01I9ALrE5GxkCHSIXALgowbGo/bH+8/wJbshQN1+JbqcbtV1bx61FDCP61N+25tW5emzRU/TOsWnn0k+YtYnxk59vIm1A Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:1c51:b0:65c:fdbc:666c with SMTP id 006d021491bc7-65d0ea9c59emr5685645eaf.42.1766622797552; Wed, 24 Dec 2025 16:33:17 -0800 (PST) Date: Wed, 24 Dec 2025 16:33:17 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <694c864d.050a0220.35954c.002e.GAE@google.com> Subject: [syzbot] [dri?] WARNING in drm_crtc_wait_one_vblank From: syzbot To: airlied@gmail.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, simona@ffwll.ch, syzkaller-bugs@googlegroups.com, tzimmermann@suse.de Content-Type: text/plain; charset="UTF-8" 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: syzbot+c9f3062e1f1e68af836a@syzkaller.appspotmail.com ------------[ 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: 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 ---------------- 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 syzkaller@googlegroups.com. 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