linux-kernel - [syzbot] [dri?] WARNING in drm_atomic_helper_wait_for

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <69381d6c.050a0220.4004e.0017.GAE@google.com>
Date: Tue, 09 Dec 2025 05:00:28 -0800
From: syzbot <syzbot+fcede535e7eb57cf5b43@...kaller.appspotmail.com>
To: airlied@...il.com, dri-devel@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org, maarten.lankhorst@...ux.intel.com, 
	mripard@...nel.org, simona@...ll.ch, syzkaller-bugs@...glegroups.com, 
	tzimmermann@...e.de
Subject: [syzbot] [dri?] WARNING in drm_atomic_helper_wait_for_vblanks (5)

Hello,

syzbot found the following issue on:

HEAD commit:    cb015814f8b6 Merge tag 'f2fs-for-6.19-rc1' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16269a1a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=dbcb767d1e1208ac
dashboard link: https://syzkaller.appspot.com/bug?extid=fcede535e7eb57cf5b43
compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-cb015814.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/81f7cff430d3/vmlinux-cb015814.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1252ad8ea70f/bzImage-cb015814.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fcede535e7eb57cf5b43@...kaller.appspotmail.com

------------[ cut here ]------------
[CRTC:37:crtc-0] vblank wait timed out
WARNING: drivers/gpu/drm/drm_atomic_helper.c:1844 at 0x0, CPU#3: kworker/3:0/34
Modules linked in:
CPU: 3 UID: 0 PID: 34 Comm: kworker/3:0 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: events drm_fb_helper_damage_work
RIP: 0010:drm_atomic_helper_wait_for_vblanks.part.0+0x766/0x8c0 drivers/gpu/drm/drm_atomic_helper.c:1844
Code: 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 0f b6 04 01 84 c0 74 08 3c 03 0f 8e 3f 01 00 00 48 8d 3d f0 9b 3a 0b 8b b5 d8 00 00 00 <67> 48 0f b9 3a e9 ed fc ff ff e8 8b 66 67 fc e9 81 fe ff ff e8 b1
RSP: 0018:ffffc900006df688 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffff11004e34023
RDX: ffff8880264b9cc0 RSI: 0000000000000025 RDI: ffffffff909219c0
RBP: ffff8880271a0040 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: ffff88801e6bd4b0 R12: dffffc0000000000
R13: ffff88802b42d300 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880d6c07000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5e2cb4af98 CR3: 00000000578af000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 drm_atomic_helper_wait_for_vblanks drivers/gpu/drm/drm_atomic_helper.c:1818 [inline]
 drm_atomic_helper_commit_tail+0xaa/0xd0 drivers/gpu/drm/drm_atomic_helper.c:1920
 commit_tail+0x334/0x410 drivers/gpu/drm/drm_atomic_helper.c:1997
 drm_atomic_helper_commit+0x300/0x380 drivers/gpu/drm/drm_atomic_helper.c:2235
 drm_atomic_commit+0x234/0x300 drivers/gpu/drm/drm_atomic.c:1743
 drm_atomic_helper_dirtyfb+0x5fd/0x780 drivers/gpu/drm/drm_damage_helper.c:183
 drm_fbdev_shmem_helper_fb_dirty+0x1cc/0x310 drivers/gpu/drm/drm_fbdev_shmem.c:117
 drm_fb_helper_fb_dirty drivers/gpu/drm/drm_fb_helper.c:346 [inline]
 drm_fb_helper_damage_work+0x2a2/0x5e0 drivers/gpu/drm/drm_fb_helper.c:369
 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
----------------
Code disassembly (best guess), 5 bytes skipped:
   0:	df 48 89             	fisttps -0x77(%rax)
   3:	f9                   	stc
   4:	48 c1 e9 03          	shr    $0x3,%rcx
   8:	0f b6 04 01          	movzbl (%rcx,%rax,1),%eax
   c:	84 c0                	test   %al,%al
   e:	74 08                	je     0x18
  10:	3c 03                	cmp    $0x3,%al
  12:	0f 8e 3f 01 00 00    	jle    0x157
  18:	48 8d 3d f0 9b 3a 0b 	lea    0xb3a9bf0(%rip),%rdi        # 0xb3a9c0f
  1f:	8b b5 d8 00 00 00    	mov    0xd8(%rbp),%esi
* 25:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2a:	e9 ed fc ff ff       	jmp    0xfffffd1c
  2f:	e8 8b 66 67 fc       	call   0xfc6766bf
  34:	e9 81 fe ff ff       	jmp    0xfffffeba
  39:	e8                   	.byte 0xe8
  3a:	b1                   	.byte 0xb1


---
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@...glegroups.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