[syzbot] [dri?] WARNING in drm_atomic_helper_wait_for_vblanks (6)

[syzbot <syzbot+45bc7264de77caad91cb@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    79bd2dded182 Merge tag 'sched_ext-for-7.1-rc4-fixes' of gi..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12282ac8580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e327ee9a867dd6b9
dashboard link: https://syzkaller.appspot.com/bug?extid=45bc7264de77caad91cb
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

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-79bd2dde.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/334fd806b634/vmlinux-79bd2dde.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dc1d1c63d028/bzImage-79bd2dde.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+45bc7264de77caad91cb@syzkaller.appspotmail.com

------------[ cut here ]------------
[CRTC:39:crtc-0] vblank wait timed out
WARNING: drivers/gpu/drm/drm_atomic_helper.c:1921 at drm_atomic_helper_wait_for_vblanks.part.0+0x738/0x8a0 drivers/gpu/drm/drm_atomic_helper.c:1921, CPU#1: kworker/1:1/54
Modules linked in:
CPU: 1 UID: 0 PID: 54 Comm: kworker/1:1 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 04/01/2014
Workqueue: events drm_fb_helper_damage_work
RIP: 0010:drm_atomic_helper_wait_for_vblanks.part.0+0x73e/0x8a0 drivers/gpu/drm/drm_atomic_helper.c:1921
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 44 01 00 00 48 8d 3d e8 b2 3a 0b 8b b3 d0 00 00 00 <67> 48 0f b9 3a e9 e1 fc ff ff e8 43 4e 60 fc e9 7c fe ff ff e8 e9
RSP: 0018:ffffc90000a7f6e8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888100fa0040 RCX: 1ffff110201f4022
RDX: ffff888025b8c780 RSI: 0000000000000027 RDI: ffffffff90e31630
RBP: dffffc0000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff88802a6c0200
FS:  0000000000000000(0000) GS:ffff8880d646a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fea94fea540 CR3: 000000002e244000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 drm_atomic_helper_wait_for_vblanks drivers/gpu/drm/drm_atomic_helper.c:1895 [inline]
 drm_atomic_helper_commit_tail+0xff/0x130 drivers/gpu/drm/drm_atomic_helper.c:1997
 commit_tail+0x338/0x430 drivers/gpu/drm/drm_atomic_helper.c:2074
 drm_atomic_helper_commit+0x303/0x380 drivers/gpu/drm/drm_atomic_helper.c:2312
 drm_atomic_commit+0x230/0x300 drivers/gpu/drm/drm_atomic.c:1789
 drm_atomic_helper_dirtyfb+0x603/0x790 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:249 [inline]
 drm_fb_helper_damage_work+0x348/0x640 drivers/gpu/drm/drm_fb_helper.c:275
 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314
 process_scheduled_works kernel/workqueue.c:3397 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	00 fc                	add    %bh,%ah
   4:	ff                   	lcall  (bad)
   5:	df 48 89             	fisttps -0x77(%rax)
   8:	f9                   	stc
   9:	48 c1 e9 03          	shr    $0x3,%rcx
   d:	0f b6 04 01          	movzbl (%rcx,%rax,1),%eax
  11:	84 c0                	test   %al,%al
  13:	74 08                	je     0x1d
  15:	3c 03                	cmp    $0x3,%al
  17:	0f 8e 44 01 00 00    	jle    0x161
  1d:	48 8d 3d e8 b2 3a 0b 	lea    0xb3ab2e8(%rip),%rdi        # 0xb3ab30c
  24:	8b b3 d0 00 00 00    	mov    0xd0(%rbx),%esi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	e9 e1 fc ff ff       	jmp    0xfffffd15
  34:	e8 43 4e 60 fc       	call   0xfc604e7c
  39:	e9 7c fe ff ff       	jmp    0xfffffeba
  3e:	e8                   	.byte 0xe8
  3f:	e9                   	.byte 0xe9


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