[syzbot] [media?] INFO: trying to register non-static key in __vb2_queue_cancel

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cc2b5f627e8c Add linux-next specific files for 20260714
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17fb04b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2290ccbf984c524f
dashboard link: https://syzkaller.appspot.com/bug?extid=2302c5dc59995fbb8089
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12d598b9580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14500789580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6836f8efb1da/disk-cc2b5f62.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0109d3477cc7/vmlinux-cc2b5f62.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c2e49e350bbf/bzImage-cc2b5f62.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2302c5...@syzkaller.appspotmail.com

em28xx 1-1:0.132: AC97 chip type couldn't be determined
em28xx 1-1:0.132: No AC97 audio processor
usb 1-1: Decoder not found
em28xx 1-1:0.132: failed to create media graph
em28xx 1-1:0.132: V4L2 device video103 deregistered
INFO: trying to register non-static key.
The code is fine but needs lockdep annotation, or maybe
you didn't initialize this object before use?
turning off the locking correctness validator.
CPU: 1 UID: 0 PID: 5649 Comm: kworker/1:3 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
Workqueue: events request_module_async
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
assign_lock_key+0x133/0x150 kernel/locking/lockdep.c:1000
register_lock_class+0xcc/0x2e0 kernel/locking/lockdep.c:1315
__lock_acquire+0xaf/0x2e40 kernel/locking/lockdep.c:5128
lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5906
rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56
spin_lock include/linux/spinlock_rt.h:45 [inline]
__wake_up_common_lock+0x2f/0x1f0 kernel/sched/wait.c:124
__vb2_queue_cancel+0x2de/0xdc0 drivers/media/common/videobuf2/videobuf2-core.c:2244
vb2_core_queue_release+0x2f/0x150 drivers/media/common/videobuf2/videobuf2-core.c:2677
vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:956 [inline]
vb2_video_unregister_device+0x15b/0x200 drivers/media/common/videobuf2/videobuf2-v4l2.c:1292
em28xx_v4l2_init+0x1c60/0x3140 drivers/media/usb/em28xx/em28xx-video.c:3097
em28xx_init_extension+0x120/0x1d0 drivers/media/usb/em28xx/em28xx-core.c:1248
process_one_work+0xaaf/0x1480 kernel/workqueue.c:3379
process_scheduled_works kernel/workqueue.c:3462 [inline]
worker_thread+0xb05/0x10d0 kernel/workqueue.c:3543
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 5649 Comm: kworker/1:3 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
Workqueue: events request_module_async
RIP: 0010:__wake_up_common kernel/sched/wait.c:104 [inline]
RIP: 0010:__wake_up_common_lock+0xd6/0x1f0 kernel/sched/wait.c:125
Code: 0f 84 d4 00 00 00 44 8b 7c 24 04 eb 13 48 ba 00 00 00 00 00 fc ff df 4c 39 ed 0f 84 ba 00 00 00 49 89 ee 48 89 e8 48 c1 e8 03 <80> 3c 10 00 74 12 4c 89 f7 e8 1c ce 93 00 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc9000595f908 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff8bcbd060 RDI: 00000000ffffffff
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1fa1890 R12: ffff88803e181b14
R13: ffff88803e181c28 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125af2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005625301fb660 CR3: 000000003774e000 CR4: 00000000003526f0
Call Trace:
<TASK>
__vb2_queue_cancel+0x2de/0xdc0 drivers/media/common/videobuf2/videobuf2-core.c:2244
vb2_core_queue_release+0x2f/0x150 drivers/media/common/videobuf2/videobuf2-core.c:2677
vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:956 [inline]
vb2_video_unregister_device+0x15b/0x200 drivers/media/common/videobuf2/videobuf2-v4l2.c:1292
em28xx_v4l2_init+0x1c60/0x3140 drivers/media/usb/em28xx/em28xx-video.c:3097
em28xx_init_extension+0x120/0x1d0 drivers/media/usb/em28xx/em28xx-core.c:1248
process_one_work+0xaaf/0x1480 kernel/workqueue.c:3379
process_scheduled_works kernel/workqueue.c:3462 [inline]
worker_thread+0xb05/0x10d0 kernel/workqueue.c:3543
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__wake_up_common kernel/sched/wait.c:104 [inline]
RIP: 0010:__wake_up_common_lock+0xd6/0x1f0 kernel/sched/wait.c:125
Code: 0f 84 d4 00 00 00 44 8b 7c 24 04 eb 13 48 ba 00 00 00 00 00 fc ff df 4c 39 ed 0f 84 ba 00 00 00 49 89 ee 48 89 e8 48 c1 e8 03 <80> 3c 10 00 74 12 4c 89 f7 e8 1c ce 93 00 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc9000595f908 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff8bcbd060 RDI: 00000000ffffffff
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1fa1890 R12: ffff88803e181b14
R13: ffff88803e181c28 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125af2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005625301fb660 CR3: 000000003774e000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
0: 0f 84 d4 00 00 00 je 0xda
6: 44 8b 7c 24 04 mov 0x4(%rsp),%r15d
b: eb 13 jmp 0x20
d: 48 ba 00 00 00 00 00 movabs $0xdffffc0000000000,%rdx
14: fc ff df
17: 4c 39 ed cmp %r13,%rbp
1a: 0f 84 ba 00 00 00 je 0xda
20: 49 89 ee mov %rbp,%r14
23: 48 89 e8 mov %rbp,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 80 3c 10 00 cmpb $0x0,(%rax,%rdx,1) <-- trapping instruction
2e: 74 12 je 0x42
30: 4c 89 f7 mov %r14,%rdi
33: e8 1c ce 93 00 call 0x93ce54
38: 48 rex.W
39: ba 00 00 00 00 mov $0x0,%edx
3e: 00 fc add %bh,%ah


---
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 syzk...@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 syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

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

[Gautam Bhadoria]

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git cc2b5f627e8ccbae1188ef2d8be3e451d7f933a5

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
lost connection to test machine



Tested on:

commit: cc2b5f62 Add linux-next specific files for 20260714
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=117a58b9580000

kernel config: https://syzkaller.appspot.com/x/.config?x=2290ccbf984c524f
dashboard link: https://syzkaller.appspot.com/bug?extid=2302c5dc59995fbb8089
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=167ff346580000

[Gautam Bhadoria]

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

cc2b5f627e8ccbae1188ef2d8be3e451d7f933a5  

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
lost connection to test machine



Tested on:

commit: cc2b5f62 Add linux-next specific files for 20260714

git tree: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=11d20b46580000

kernel config: https://syzkaller.appspot.com/x/.config?x=2290ccbf984c524f
dashboard link: https://syzkaller.appspot.com/bug?extid=2302c5dc59995fbb8089
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=17d658b9580000

[Gautam Bhadoria]

#syz test

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
lost connection to test machine



Tested on:

commit: cc2b5f62 Add linux-next specific files for 20260714

git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10b844b9580000

kernel config: https://syzkaller.appspot.com/x/.config?x=2290ccbf984c524f
dashboard link: https://syzkaller.appspot.com/bug?extid=2302c5dc59995fbb8089
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Note: no patches were applied.

[Gautam Bhadoria]

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

cc2b5f627e8ccbae1188ef2d8be3e451d7f933a5

[syzbot]

> #syz test https://

I've failed to parse your command.
Did you perhaps forget to provide the branch name, or added an extra ':'?
Please use one of the two supported formats:
1. #syz test
2. #syz test: repo branch-or-commit-hash
Note the lack of ':' in option 1.

> git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> cc2b5f627e8ccbae1188ef2d8be3e451d7f933a5

[Gautam Bhadoria]

it was an empty test without any patch so why is still giving me 

" syzbot has tested the proposed patch but the reproducer is still triggering an issue:
lost connection to test machine  "

[Gautam Bhadoria]

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

cc2b5f627e8ccbae1188ef2d8be3e451d7f933a5

[syzbot]

> #syz test: https://

"https://" does not look like a valid git repo address.

> git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

[Gautam Bhadoria]

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

cc2b5f627e8ccbae1188ef2d8be3e451d7f933a5

[syzbot]

> #syz test git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

I've failed to parse your command.
Did you perhaps forget to provide the branch name, or added an extra ':'?
Please use one of the two supported formats:
1. #syz test
2. #syz test: repo branch-or-commit-hash
Note the lack of ':' in option 1.

> cc2b5f627e8ccbae1188ef2d8be3e451d7f933a5

[Gautam Bhadoria]

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git  cc2b5f627e8ccbae1188ef2d8be3e451d7f933a5

[syzbot]

[Gautam Bhadoria]

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git  cc2b5f627e8ccbae1188ef2d8be3e451d7f933a5

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
lost connection to test machine



Tested on:

commit: cc2b5f62 Add linux-next specific files for 20260714

git tree: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=17858c32580000

[Gautam Bhadoria]

  The syzbot test request is failing with "lost connection to test machine" even when sending #syz test without any patch. This appears to be unrelated to the proposed fix and may indicate a problem with the current syzbot test environment.  

[Gautam Bhadoria]

#syz test

[Gautam Bhadoria]

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

928][ T1] pci_bus 0000:00: resource 7 [io 0xa000-0xbfff window]
[ 5.040994][ T1] pci_bus 0000:00: resource 8 [mem 0x000a0000-0x000bffff window]
[ 5.041069][ T1] pci_bus 0000:00: resource 9 [mem 0xc0000000-0xfebfefff window]
[ 5.056552][ T1] pci 0000:00:00.0: Limiting direct PCI/PCI transfers
[ 5.057829][ T1] PCI: CLS 0 bytes, default 64
[ 5.062697][ T1] PCI-DMA: Using software bounce buffering for IO (SWIOTLB)
[ 5.062755][ T1] software IO TLB: mapped [mem 0x00000000b4600000-0x00000000b8600000] (64MB)
[ 5.091103][ T1] ACPI: bus type thunderbolt registered
[ 5.110651][ T70] kworker/u8:4 (70) used greatest stack depth: 26408 bytes left
[ 5.125500][ T1] RAPL PMU: API unit is 2^-32 Joules, 0 fixed counters, 10737418240 ms ovfl timer
[ 5.169904][ T1] kvm_amd: CPU 0 isn't AMD or Hygon
[ 5.169939][ T1] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x1fb63109b96, max_idle_ns: 440795265316 ns
[ 5.177074][ T1] clocksource: Switched to clocksource tsc
[ 5.256175][ T1] Initialise system trusted keyrings
[ 5.264090][ T1] workingset: timestamp_bits=40 (anon: 35) max_order=21 bucket_order=0 (anon: 0)
[ 5.282669][ T1] DLM installed
[ 5.293488][ T1] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[ 5.312965][ T1] NFS: Registering the id_resolver key type
[ 5.313172][ T1] Key type id_resolver registered
[ 5.313186][ T1] Key type id_legacy registered
[ 5.313573][ T1] nfs4filelayout_init: NFSv4 File Layout Driver Registering...
[ 5.313793][ T1] nfs4flexfilelayout_init: NFSv4 Flexfile Layout Driver Registering...
[ 5.334869][ T1] smbdirect: subsystem loading...
[ 5.353534][ T1] smbdirect: subsystem loaded
[ 5.378220][ T1] Key type cifs.spnego registered
[ 5.378646][ T1] Key type cifs.idmap registered
[ 5.388711][ T1] ntfs3: Enabled Linux POSIX ACLs support
[ 5.388725][ T1] ntfs3: Read-only LZX/Xpress compression included
[ 5.389252][ T1] jffs2: version 2.2. (NAND) (SUMMARY) © 2001-2006 Red Hat, Inc.
[ 5.401586][ T1] romfs: ROMFS MTD (C) 2007 Red Hat, Inc.
[ 5.401943][ T1] QNX4 filesystem 0.2.3 registered.
[ 5.402089][ T1] qnx6: QNX6 filesystem 1.0.0 registered.
[ 5.403903][ T1] fuse: init (API version 7.45)
[ 5.408825][ T1] orangefs_debugfs_init: called with debug mask: :none: :0:
[ 5.424152][ T1] orangefs_init: module version upstream loaded
[ 5.425732][ T1] JFS: nTxBlock = 8192, nTxLock = 65536
[ 5.452094][ T1] SGI XFS with ACLs, security attributes, realtime, scrub, repair, quota, no debug enabled
[ 5.482169][ T1] 9p: Installing v9fs 9p2000 file system support
[ 5.483755][ T1] NILFS version 2 loaded
[ 5.483769][ T1] befs: version: 0.9.3
[ 5.485358][ T1] ocfs2: Registered cluster interface o2cb
[ 5.486741][ T1] ocfs2: Registered cluster interface user
[ 5.489406][ T1] OCFS2 User DLM kernel interface loaded
[ 5.542362][ T1] gfs2: GFS2 installed
[ 5.567883][ T1] ceph: loaded (mds proto 32)
[ 5.586370][ T1] NET: Registered PF_ALG protocol family
[ 5.587688][ T1] async_tx: api initialized (async)
[ 5.587756][ T1] Key type asymmetric registered
[ 5.587848][ T1] Asymmetric key parser 'x509' registered
[ 5.587866][ T1] Asymmetric key parser 'pkcs8' registered
[ 5.587883][ T1] Key type pkcs7_test registered
[ 5.589016][ T1] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 239)
[ 5.603067][ T1] io scheduler mq-deadline registered
[ 5.603139][ T1] io scheduler kyber registered
[ 5.604834][ T1] io scheduler bfq registered
[ 5.649355][ T1] input: Power Button as /devices/platform/LNXPWRBN:00/input/input0
[ 5.662681][ T1] ACPI: button: Power Button [PWRF]
[ 5.667457][ T1] input: Sleep Button as /devices/platform/LNXSLPBN:00/input/input1
[ 5.681011][ T1] ACPI: button: Sleep Button [SLPF]
[ 5.718524][ T1] ioatdma: Intel(R) QuickData Technology Driver 5.00
[ 5.772183][ T10] ACPI: \_SB_.LNKC: Enabled at IRQ 11
[ 5.774597][ T10] virtio-pci 0000:00:03.0: virtio_pci: leaving for legacy driver
[ 5.821763][ T10] ACPI: \_SB_.LNKD: Enabled at IRQ 10
[ 5.821966][ T10] virtio-pci 0000:00:04.0: virtio_pci: leaving for legacy driver
[ 5.872047][ T10] ACPI: \_SB_.LNKB: Enabled at IRQ 10
[ 5.872225][ T10] virtio-pci 0000:00:06.0: virtio_pci: leaving for legacy driver
[ 5.908391][ T10] virtio-pci 0000:00:07.0: virtio_pci: leaving for legacy driver
[ 6.978343][ T1] N_HDLC line discipline registered with maxframe=4096
[ 6.984196][ T1] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[ 7.005107][ T1] 00:02: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
[ 7.038077][ T1] 00:03: ttyS1 at I/O 0x2f8 (irq = 3, base_baud = 115200) is a 16550A
[ 7.067193][ T1] 00:04: ttyS2 at I/O 0x3e8 (irq = 6, base_baud = 115200) is a 16550A
[ 7.095230][ T1] 00:05: ttyS3 at I/O 0x2e8 (irq = 7, base_baud = 115200) is a 16550A
[ 7.150291][ T1] Non-volatile memory driver v1.3
[ 7.194453][ T1] usbcore: registered new interface driver xillyusb
[ 7.207219][ T1] ACPI: bus type drm_connector registered
[ 7.219124][ T1] [drm] Initialized vgem 1.0.0 for vgem on minor 0
[ 7.230757][ T1] ------------[ cut here ]------------
[ 7.230772][ T1] [PLANE:35:plane-0] pixel format with alpha exposed but blend mode not setup
[ 7.230797][ T1] WARNING: drivers/gpu/drm/drm_mode_config.c:873 at drm_mode_config_validate+0x1c6d/0x1e60, CPU#1: swapper/0/1
[ 7.230848][ T1] Modules linked in:
[ 7.230896][ T1] CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
[ 7.230921][ T1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
[ 7.230941][ T1] RIP: 0010:drm_mode_config_validate+0x1cae/0x1e60
[ 7.230980][ T1] Code: 0f 85 ae 00 00 00 4d 8d 77 10 8b 6d 00 4c 89 f0 48 c1 e8 03 80 3c 18 00 74 08 4c 89 f7 e8 6a 80 ae fc 49 8b 16 4c 89 ef 89 ee <67> 48 0f b9 3a eb 05 e8 a6 39 42 fc 49 bd 00 00 00 00 00 fc ff df
[ 7.231012][ T1] RSP: 0000:ffffc90000067810 EFLAGS: 00010246
[ 7.231030][ T1] RAX: 1ffff11004e4a808 RBX: dffffc0000000000 RCX: ffff88801d6eddc0
[ 7.231047][ T1] RDX: ffff888026f1ab80 RSI: 0000000000000023 RDI: ffffffff8fdc0940
[ 7.231063][ T1] RBP: 0000000000000023 R08: 0000000000000000 R09: 0000000000000000
[ 7.231077][ T1] R10: dffffc0000000000 R11: fffffbfff1fa18f0 R12: dffffc0000000000
[ 7.231093][ T1] R13: ffffffff8fdc0940 R14: ffff888027254040 R15: ffff888027254030
[ 7.231110][ T1] FS: 0000000000000000(0000) GS:ffff888125af2000(0000) knlGS:0000000000000000
[ 7.231129][ T1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 7.231144][ T1] CR2: 0000000000000000 CR3: 000000000e1b0000 CR4: 00000000003526f0
[ 7.231162][ T1] Call Trace:
[ 7.231170][ T1] <TASK>
[ 7.231194][ T1] ? debugfs_create_file_full+0x3f/0x60
[ 7.231231][ T1] drm_dev_register+0x7f/0xd80
[ 7.231266][ T1] vkms_create+0x40d/0x4f0
[ 7.231292][ T1] ? __pfx_vkms_init+0x10/0x10
[ 7.231315][ T1] vkms_init+0x57/0x80
[ 7.231337][ T1] do_one_initcall+0x250/0x870
[ 7.231366][ T1] ? __pfx_vkms_init+0x10/0x10
[ 7.231389][ T1] ? __pfx_do_one_initcall+0x10/0x10
[ 7.231422][ T1] ? clockevents_program_event+0x491/0x630
[ 7.231451][ T1] ? __pfx___schedule+0x10/0x10
[ 7.231514][ T1] ? irqentry_exit+0x218/0x8f0
[ 7.231538][ T1] ? lockdep_hardirqs_on+0x7a/0x110
[ 7.231561][ T1] ? irqentry_exit+0x218/0x8f0
[ 7.231602][ T1] ? strlen+0x35/0x70
[ 7.231627][ T1] ? next_arg+0x4a0/0x5e0
[ 7.231654][ T1] ? parameq+0x14d/0x170
[ 7.231690][ T1] ? parse_args+0x9c3/0xad0
[ 7.231737][ T1] ? trace_kmalloc+0x2a/0xf0
[ 7.231771][ T1] ? rcu_is_watching+0x15/0xb0
[ 7.231820][ T1] do_initcall_level+0x10a/0x1a0
[ 7.231852][ T1] ? kernel_init+0x22/0x1d0
[ 7.231880][ T1] do_initcalls+0x59/0xa0
[ 7.231912][ T1] kernel_init_freeable+0x29d/0x3e0
[ 7.231941][ T1] ? __pfx_kernel_init+0x10/0x10
[ 7.231970][ T1] kernel_init+0x22/0x1d0
[ 7.232006][ T1] ? __pfx_kernel_init+0x10/0x10
[ 7.232033][ T1] ret_from_fork+0x514/0xb70
[ 7.232066][ T1] ? __pfx_ret_from_fork+0x10/0x10
[ 7.232098][ T1] ? __switch_to+0xc89/0x1420
[ 7.232127][ T1] ? __pfx_kernel_init+0x10/0x10
[ 7.232157][ T1] ret_from_fork_asm+0x1a/0x30
[ 7.232203][ T1] </TASK>
[ 7.232214][ T1] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 7.232230][ T1] CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
[ 7.232254][ T1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
[ 7.232266][ T1] Call Trace:
[ 7.232274][ T1] <TASK>
[ 7.232283][ T1] vpanic+0x56c/0xa60
[ 7.232305][ T1] ? __pfx__printk+0x10/0x10
[ 7.232330][ T1] ? __pfx_vpanic+0x10/0x10
[ 7.232349][ T1] ? is_bpf_text_address+0x292/0x2b0
[ 7.232374][ T1] ? is_bpf_text_address+0x26/0x2b0
[ 7.232407][ T1] panic+0xc5/0xd0
[ 7.232428][ T1] ? __pfx_panic+0x10/0x10
[ 7.232458][ T1] ? ret_from_fork_asm+0x1a/0x30
[ 7.232492][ T1] __warn+0x315/0x4c0
[ 7.232513][ T1] ? drm_mode_config_validate+0x1c6d/0x1e60
[ 7.232547][ T1] ? drm_mode_config_validate+0x1c6d/0x1e60
[ 7.232579][ T1] __report_bug+0x276/0x570
[ 7.232605][ T1] ? drm_mode_config_validate+0x1c6d/0x1e60
[ 7.232640][ T1] ? __pfx___report_bug+0x10/0x10
[ 7.232669][ T1] ? _raw_spin_unlock_irqrestore+0x30/0x80
[ 7.232692][ T1] ? lockdep_hardirqs_on+0x7a/0x110
[ 7.232717][ T1] ? rt_mutex_slowunlock+0x4ee/0xa20
[ 7.232752][ T1] report_bug_entry+0x19a/0x290
[ 7.232775][ T1] ? drm_mode_config_validate+0x1cae/0x1e60
[ 7.232806][ T1] ? drm_mode_config_validate+0x1cb3/0x1e60
[ 7.232836][ T1] handle_bug+0xce/0x200
[ 7.232862][ T1] exc_invalid_op+0x1a/0x50
[ 7.232888][ T1] asm_exc_invalid_op+0x1a/0x20
[ 7.232909][ T1] RIP: 0010:drm_mode_config_validate+0x1cae/0x1e60
[ 7.232941][ T1] Code: 0f 85 ae 00 00 00 4d 8d 77 10 8b 6d 00 4c 89 f0 48 c1 e8 03 80 3c 18 00 74 08 4c 89 f7 e8 6a 80 ae fc 49 8b 16 4c 89 ef 89 ee <67> 48 0f b9 3a eb 05 e8 a6 39 42 fc 49 bd 00 00 00 00 00 fc ff df
[ 7.232959][ T1] RSP: 0000:ffffc90000067810 EFLAGS: 00010246
[ 7.232977][ T1] RAX: 1ffff11004e4a808 RBX: dffffc0000000000 RCX: ffff88801d6eddc0
[ 7.233001][ T1] RDX: ffff888026f1ab80 RSI: 0000000000000023 RDI: ffffffff8fdc0940
[ 7.233017][ T1] RBP: 0000000000000023 R08: 0000000000000000 R09: 0000000000000000
[ 7.233030][ T1] R10: dffffc0000000000 R11: fffffbfff1fa18f0 R12: dffffc0000000000
[ 7.233046][ T1] R13: ffffffff8fdc0940 R14: ffff888027254040 R15: ffff888027254030
[ 7.233087][ T1] ? debugfs_create_file_full+0x3f/0x60
[ 7.233122][ T1] drm_dev_register+0x7f/0xd80
[ 7.233157][ T1] vkms_create+0x40d/0x4f0
[ 7.233182][ T1] ? __pfx_vkms_init+0x10/0x10
[ 7.233204][ T1] vkms_init+0x57/0x80
[ 7.233226][ T1] do_one_initcall+0x250/0x870
[ 7.233255][ T1] ? __pfx_vkms_init+0x10/0x10
[ 7.233277][ T1] ? __pfx_do_one_initcall+0x10/0x10
[ 7.233310][ T1] ? clockevents_program_event+0x491/0x630
[ 7.233337][ T1] ? __pfx___schedule+0x10/0x10
[ 7.233384][ T1] ? irqentry_exit+0x218/0x8f0
[ 7.233406][ T1] ? lockdep_hardirqs_on+0x7a/0x110
[ 7.233428][ T1] ? irqentry_exit+0x218/0x8f0
[ 7.233468][ T1] ? strlen+0x35/0x70
[ 7.233492][ T1] ? next_arg+0x4a0/0x5e0
[ 7.233518][ T1] ? parameq+0x14d/0x170
[ 7.233552][ T1] ? parse_args+0x9c3/0xad0
[ 7.233599][ T1] ? trace_kmalloc+0x2a/0xf0
[ 7.233631][ T1] ? rcu_is_watching+0x15/0xb0
[ 7.233660][ T1] do_initcall_level+0x10a/0x1a0
[ 7.233690][ T1] ? kernel_init+0x22/0x1d0
[ 7.233718][ T1] do_initcalls+0x59/0xa0
[ 7.233747][ T1] kernel_init_freeable+0x29d/0x3e0
[ 7.233775][ T1] ? __pfx_kernel_init+0x10/0x10
[ 7.233805][ T1] kernel_init+0x22/0x1d0
[ 7.233831][ T1] ? __pfx_kernel_init+0x10/0x10
[ 7.233857][ T1] ret_from_fork+0x514/0xb70
[ 7.233888][ T1] ? __pfx_ret_from_fork+0x10/0x10
[ 7.233918][ T1] ? __switch_to+0xc89/0x1420
[ 7.233945][ T1] ? __pfx_kernel_init+0x10/0x10
[ 7.233975][ T1] ret_from_fork_asm+0x1a/0x30
[ 7.234035][ T1] </TASK>
[ 7.234204][ T1] Kernel Offset: disabled


syzkaller build log:
go env (err=<nil>)
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='auto'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build3354858300=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs-2/linux/gopath/src/github.com/google/syzkaller/go.mod'
GOMODCACHE='/syzkaller/jobs-2/linux/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/syzkaller/jobs-2/linux/gopath'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/syzkaller/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.26.0'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at 2130f68232
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=2130f682322a1c2ef698e3c27a2b97e89e96142f -X github.com/google/syzkaller/prog.gitRevisionDate=20260713-120227" ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=2130f682322a1c2ef698e3c27a2b97e89e96142f -X github.com/google/syzkaller/prog.gitRevisionDate=20260713-120227" ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=2130f682322a1c2ef698e3c27a2b97e89e96142f -X github.com/google/syzkaller/prog.gitRevisionDate=20260713-120227" -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_amd64
g++ -o ./bin/linux_amd64/syz-executor executor/executor.cc \
-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -std=c++17 -I. -Iexecutor/_include -DGOOS_linux=1 -DGOARCH_amd64=1 \
-DHOSTGOOS_linux=1 -DGIT_REVISION=\"2130f682322a1c2ef698e3c27a2b97e89e96142f\"
/usr/bin/ld: /tmp/ccNrC6p7.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x386): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
./tools/check-syzos.sh 2>/dev/null


Error text is too large and was truncated, full error text is at:
https://syzkaller.appspot.com/x/error.txt?x=117ff4b9580000


Tested on:

commit: b8809969 Add linux-next specific files for 20260715
git tree: linux-next
kernel config: https://syzkaller.appspot.com/x/.config?x=6a6b64f65d709086

[Gautam Bhadoria]

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
cc2b5f627e8ccbae1188ef2d8be3e451d7f933a5

diff --git a/drivers/media/usb/em28xx/em28xx-video.c
b/drivers/media/usb/em28xx/em28xx-video.c
index c418add65b..d93f1b5049 100644
--- a/drivers/media/usb/em28xx/em28xx-video.c
+++ b/drivers/media/usb/em28xx/em28xx-video.c
@@ -1410,6 +1410,9 @@ static int em28xx_vb2_setup(struct em28xx *dev)
if (rc < 0)
return rc;

+ if (!em28xx_vbi_supported(dev))
+ return 0;
+
/* Setup Videobuf2 for VBI capture */
q = &v4l2->vb_vbiq;
q->type = V4L2_BUF_TYPE_VBI_CAPTURE;
@@ -2416,7 +2419,7 @@ static int em28xx_v4l2_fini(struct em28xx *dev)
if (video_is_registered(&v4l2->radio_dev)) {
dev_info(&dev->intf->dev, "V4L2 device %s deregistered\n",
video_device_node_name(&v4l2->radio_dev));
- vb2_video_unregister_device(&v4l2->radio_dev);
+ video_unregister_device(&v4l2->radio_dev);
}
if (video_is_registered(&v4l2->vbi_dev)) {
dev_info(&dev->intf->dev, "V4L2 device %s deregistered\n",
@@ -2954,6 +2957,7 @@ static int em28xx_v4l2_init(struct em28xx *dev)
mutex_init(&v4l2->vb_vbi_queue_lock);
v4l2->vdev.queue = &v4l2->vb_vidq;
v4l2->vdev.queue->lock = &v4l2->vb_queue_lock;
+ v4l2->vb_vbiq.lock = &v4l2->vb_vbi_queue_lock;
v4l2->vdev.device_caps = V4L2_CAP_READWRITE | V4L2_CAP_VIDEO_CAPTURE |
V4L2_CAP_STREAMING;
if (dev->int_audio_type != EM28XX_INT_AUDIO_NONE)
@@ -2983,6 +2987,11 @@ static int em28xx_v4l2_init(struct em28xx *dev)
if (dev->chip_id == CHIP_ID_EM2828X || dev->board.decoder == EM28XX_BUILTIN)
v4l2_disable_ioctl(&v4l2->vdev, VIDIOC_ENUM_FRAMESIZES);

+ /* Initialize the queues before registering devices that reference them. */
+ ret = em28xx_vb2_setup(dev);
+ if (ret)
+ goto unregister_dev;
+
/* register v4l2 video video_device */
ret = video_register_device(&v4l2->vdev, VFL_TYPE_VIDEO,
video_nr[dev->devno]);
@@ -3068,9 +3077,6 @@ static int em28xx_v4l2_init(struct em28xx *dev)
/* Save some power by putting tuner to sleep */
v4l2_device_call_all(&v4l2->v4l2_dev, 0, tuner, standby);

- /* initialize videobuf2 stuff */
- em28xx_vb2_setup(dev);
-
dev_info(&dev->intf->dev,
"V4L2 extension successfully initialized\n");

@@ -3082,7 +3088,7 @@ static int em28xx_v4l2_init(struct em28xx *dev)
dev_info(&dev->intf->dev,
"V4L2 device %s deregistered\n",
video_device_node_name(&v4l2->radio_dev));
- vb2_video_unregister_device(&v4l2->radio_dev);
+ video_unregister_device(&v4l2->radio_dev);
}
if (video_is_registered(&v4l2->vbi_dev)) {
dev_info(&dev->intf->dev,

[Pimyn Girgis]

Thanks for the report! We created
https://github.com/google/syzkaller/issues/7621 to track the issue.

> --
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--
Ⲡⲟⲓⲙⲏⲛ Ⲅⲉⲱⲣⲅⲓⲟⲥ - Pimyn Girgis
Software Engineer
Kernel Dynamic Analysis
pi...@google.com

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:

lost connection to test machine

Tested on:

commit: cc2b5f62 Add linux-next specific files for 20260714
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

console output: https://syzkaller.appspot.com/x/log.txt?x=103bd4b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2290ccbf984c524f

dashboard link: https://syzkaller.appspot.com/bug?extid=2302c5dc59995fbb8089
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=17000cb9580000