[syzbot] [dri?] WARNING in drm_atomic_helper_wait_for_vblanks (4)

Sat May 31 21:45:25 UTC 2025

Hello,

syzbot found the following issue on:

HEAD commit:    914873bc7df9 Merge tag 'x86-build-2025-05-25' of git://git..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1550fdf4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=99deacfb6378f156
dashboard link: https://syzkaller.appspot.com/bug?extid=70c83229f190c4cbf649
compiler:       arm-linux-gnueabi-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/98a89b9f34e4/non_bootable_disk-914873bc.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/55cb8ce834df/vmlinux-914873bc.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6c2325ebf21a/zImage-914873bc.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+70c83229f190c4cbf649 at syzkaller.appspotmail.com

input: AT Raw Set 2 keyboard as /devices/platform/bus at 8000000/bus at 8000000:motherboard-bus/bus at 8000000:motherboard-bus:iofpga-bus at 300000000/1c060000.kmi/serio0/input/input0
input: ImExPS/2 Generic Explorer Mouse as /devices/platform/bus at 8000000/bus at 8000000:motherboard-bus/bus at 8000000:motherboard-bus:iofpga-bus at 300000000/1c070000.kmi/serio1/input/input2
------------[ cut here ]------------
WARNING: CPU: 1 PID: 47 at drivers/gpu/drm/drm_atomic_helper.c:1720 drm_atomic_helper_wait_for_vblanks.part.0+0x280/0x288 drivers/gpu/drm/drm_atomic_helper.c:1720
[CRTC:34:crtc-0] vblank wait timed out
Modules linked in:
Kernel panic - not syncing: kernel: panic_on_warn set ...
CPU: 1 UID: 0 PID: 47 Comm: kworker/1:1 Not tainted 6.15.0-syzkaller #0 PREEMPT 
Hardware name: ARM-Versatile Express
Workqueue: events output_poll_execute
Call trace: 
[<802019e4>] (dump_backtrace) from [<80201ae0>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:8282083c r5:00000000 r4:822585bc
[<80201ac8>] (show_stack) from [<802204e0>] (__dump_stack lib/dump_stack.c:94 [inline])
[<80201ac8>] (show_stack) from [<802204e0>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120)
[<8022048c>] (dump_stack_lvl) from [<80220520>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r5:00000000 r4:82a6fd1c
[<80220508>] (dump_stack) from [<802025f8>] (panic+0x120/0x374 kernel/panic.c:354)
[<802024d8>] (panic) from [<80259160>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<802024d8>] (panic) from [<80259160>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8280c604 r2:00000001 r1:8223f214 r0:82246c00
 r7:80ae0220
[<802590ec>] (check_panic_on_warn) from [<802592c4>] (__warn+0x80/0x188 kernel/panic.c:749)
[<80259244>] (__warn) from [<802595b4>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:784)
 r8:00000009 r7:822d4db8 r6:df921bb4 r5:832e0000 r4:00000000
[<802593d0>] (warn_slowpath_fmt) from [<80ae0220>] (drm_atomic_helper_wait_for_vblanks.part.0+0x280/0x288 drivers/gpu/drm/drm_atomic_helper.c:1720)
 r10:83833000 r9:00000001 r8:00000000 r7:00000000 r6:8334b500 r5:843cf050
 r4:00000000
[<80adffa0>] (drm_atomic_helper_wait_for_vblanks.part.0) from [<80ae166c>] (drm_atomic_helper_wait_for_vblanks drivers/gpu/drm/drm_atomic_helper.c:1696 [inline])
[<80adffa0>] (drm_atomic_helper_wait_for_vblanks.part.0) from [<80ae166c>] (drm_atomic_helper_commit_tail+0x84/0x94 drivers/gpu/drm/drm_atomic_helper.c:1796)
 r10:838a1c1c r9:00000000 r8:00000000 r7:00000001 r6:be5c55c0 r5:83833000
 r4:8334b500
[<80ae15e8>] (drm_atomic_helper_commit_tail) from [<80ae2d2c>] (commit_tail+0x178/0x19c drivers/gpu/drm/drm_atomic_helper.c:1873)
 r5:00000000 r4:8334b500
[<80ae2bb4>] (commit_tail) from [<80ae2eb8>] (drm_atomic_helper_commit+0x150/0x174 drivers/gpu/drm/drm_atomic_helper.c:2111)
 r9:00000000 r8:8334b52c r7:00000000 r6:83833000 r5:00000000 r4:8334b500
[<80ae2d68>] (drm_atomic_helper_commit) from [<80a9cff0>] (drm_atomic_commit+0xcc/0x100 drivers/gpu/drm/drm_atomic.c:1518)
 r9:00000000 r8:843cf520 r7:00000001 r6:00000001 r5:83833000 r4:8334b500
[<80a9cf24>] (drm_atomic_commit) from [<80ad4c3c>] (drm_client_modeset_commit_atomic+0x21c/0x25c drivers/gpu/drm/drm_client_modeset.c:1079)
 r5:838331ac r4:8334b500
[<80ad4a20>] (drm_client_modeset_commit_atomic) from [<80ad4d54>] (drm_client_modeset_commit_locked+0x64/0x18c drivers/gpu/drm/drm_client_modeset.c:1182)
 r10:838331ec r9:00000000 r8:822d3f0c r7:844b2a18 r6:844b2a00 r5:83833000
 r4:83833000
[<80ad4cf0>] (drm_client_modeset_commit_locked) from [<80ad4ea8>] (drm_client_modeset_commit+0x2c/0x48 drivers/gpu/drm/drm_client_modeset.c:1208)
 r9:00000000 r8:822d3f0c r7:838330ac r6:844b2ab8 r5:83833000 r4:844b2a00
[<80ad4e7c>] (drm_client_modeset_commit) from [<80aeef7c>] (__drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:237 [inline])
[<80ad4e7c>] (drm_client_modeset_commit) from [<80aeef7c>] (__drm_fb_helper_restore_fbdev_mode_unlocked+0xa4/0xd8 drivers/gpu/drm/drm_fb_helper.c:216)
 r5:844b2a00 r4:00000000
[<80aeeed8>] (__drm_fb_helper_restore_fbdev_mode_unlocked) from [<80aeeec8>] (drm_fb_helper_set_par drivers/gpu/drm/drm_fb_helper.c:1359 [inline])
[<80aeeed8>] (__drm_fb_helper_restore_fbdev_mode_unlocked) from [<80aeeec8>] (drm_fb_helper_hotplug_event+0xf8/0x108 drivers/gpu/drm/drm_fb_helper.c:1970)
 r7:838330ac r6:83833000 r5:844b2ab8 r4:844b2a00
[<80aeedd0>] (drm_fb_helper_hotplug_event) from [<80aef428>] (drm_fbdev_client_hotplug+0x24/0xc8 drivers/gpu/drm/clients/drm_fbdev_client.c:43)
 r5:83833000 r4:844b2a00
[<80aef404>] (drm_fbdev_client_hotplug) from [<80ad44b4>] (drm_client_hotplug drivers/gpu/drm/drm_client_event.c:69 [inline])
[<80aef404>] (drm_fbdev_client_hotplug) from [<80ad44b4>] (drm_client_dev_hotplug drivers/gpu/drm/drm_client_event.c:98 [inline])
[<80aef404>] (drm_fbdev_client_hotplug) from [<80ad44b4>] (drm_client_dev_hotplug+0xd8/0x130 drivers/gpu/drm/drm_client_event.c:84)
 r7:838330ac r6:83833000 r5:83833098 r4:844b2a00
[<80ad43dc>] (drm_client_dev_hotplug) from [<80aea6b8>] (drm_kms_helper_hotplug_event drivers/gpu/drm/drm_probe_helper.c:735 [inline])
[<80ad43dc>] (drm_client_dev_hotplug) from [<80aea6b8>] (output_poll_execute+0x27c/0x2c8 drivers/gpu/drm/drm_probe_helper.c:847)
 r9:00000000 r8:838330d8 r7:00000001 r6:83833000 r5:00000001 r4:832a0000
[<80aea43c>] (output_poll_execute) from [<8027eb9c>] (process_one_work+0x1b4/0x4f4 kernel/workqueue.c:3238)
 r10:83016070 r9:83018205 r8:832e0000 r7:ddde2d80 r6:83018200 r5:838331ec
 r4:832a0000
[<8027e9e8>] (process_one_work) from [<8027f7e4>] (process_scheduled_works kernel/workqueue.c:3319 [inline])
[<8027e9e8>] (process_one_work) from [<8027f7e4>] (worker_thread+0x1fc/0x3d8 kernel/workqueue.c:3400)
 r10:61c88647 r9:832e0000 r8:832a002c r7:82804d40 r6:ddde2d80 r5:ddde2da0
 r4:832a0000
[<8027f5e8>] (worker_thread) from [<80286810>] (kthread+0x12c/0x280 kernel/kthread.c:464)
 r10:00000000 r9:832a0000 r8:8027f5e8 r7:df879e60 r6:832a0080 r5:832e0000
 r4:00000001
[<802866e4>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137)
Exception stack(0xdf921fb0 to 0xdf921ff8)
1fa0:                                     00000000 00000000 00000000 00000000
1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
1fe0: 00000000 00000000 00000000 00000000 00000013 00000000
 r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:802866e4
 r4:832a1000
Rebooting in 86400 seconds..

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