WARNING in vidtv_start_feed

Status: upstream: reported on 2026/08/25 22:21
Subsystems: media
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+525fda837bd5fc2be560@syzkaller.appspotmail.com
First crash: 5d15h, last: 2d23h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
db7c096c assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in vidtv_start_feed 2026/08/23 00:01 2026/08/23 00:01 2026/08/23 01:03 1e72964b
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [media?] WARNING in vidtv_start_feed 0 (1) 2026/08/25 22:21

Sample crash report:
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(lock->magic != lock)
WARNING: kernel/locking/mutex.c:625 at __mutex_lock_common kernel/locking/mutex.c:625 [inline], CPU#1: syz.0.342/7078
WARNING: kernel/locking/mutex.c:625 at __mutex_lock+0x12e6/0x1550 kernel/locking/mutex.c:821, CPU#1: syz.0.342/7078
Modules linked in:
CPU: 1 UID: 0 PID: 7078 Comm: syz.0.342 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:__mutex_lock_common kernel/locking/mutex.c:625 [inline]
RIP: 0010:__mutex_lock+0x12ed/0x1550 kernel/locking/mutex.c:821
Code: 29 79 90 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 47 02 00 00 83 3d 77 a5 9a 04 00 75 13 48 8d 3d ba 9b 9d 04 48 c7 c6 80 fe 0c 8c <67> 48 0f b9 3a 90 e9 67 ee ff ff 90 0f 0b 90 e9 3a f2 ff ff 90 0f
RSP: 0018:ffffc900051b7960 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000080000
RDX: ffffc9001174a000 RSI: ffffffff8c0cfe80 RDI: ffffffff907c1f80
RBP: ffffc900051b7af0 R08: ffffffff90792933 R09: 1ffffffff20f2526
R10: dffffc0000000000 R11: fffffbfff20f2527 R12: ffff888026075128
R13: 0000000000000000 R14: 1ffff92000a36f40 R15: 0000000000000000
FS:  00007fad388b86c0(0000) GS:ffff888124e0c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33316ff8 CR3: 000000002e6c2000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 vidtv_start_feed+0x102/0x5a0 drivers/media/test-drivers/vidtv/vidtv_bridge.c:233
 dmx_ts_feed_start_filtering+0x129/0x220 drivers/media/dvb-core/dvb_demux.c:747
 dvb_dmxdev_start_feed drivers/media/dvb-core/dmxdev.c:658 [inline]
 dvb_dmxdev_filter_start+0x434/0x10d0 drivers/media/dvb-core/dmxdev.c:769
 dvb_demux_do_ioctl+0x48b/0x540 drivers/media/dvb-core/dmxdev.c:1099
 dvb_usercopy+0x199/0x2e0 drivers/media/dvb-core/dvbdev.c:996
 dvb_demux_ioctl+0x29/0x40 drivers/media/dvb-core/dmxdev.c:1208
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fad3799e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fad388b8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fad37c26180 RCX: 00007fad3799e0d9
RDX: 00002000000000c0 RSI: 0000000040146f2c RDI: 0000000000000003
RBP: 00007fad37a35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fad37c26218 R14: 00007fad37c26180 R15: 00007fff575e5288
 </TASK>
----------------
Code disassembly (best guess):
   0:	29 79 90             	sub    %edi,-0x70(%rcx)
   3:	48 c1 e8 03          	shr    $0x3,%rax
   7:	0f b6 04 18          	movzbl (%rax,%rbx,1),%eax
   b:	84 c0                	test   %al,%al
   d:	0f 85 47 02 00 00    	jne    0x25a
  13:	83 3d 77 a5 9a 04 00 	cmpl   $0x0,0x49aa577(%rip)        # 0x49aa591
  1a:	75 13                	jne    0x2f
  1c:	48 8d 3d ba 9b 9d 04 	lea    0x49d9bba(%rip),%rdi        # 0x49d9bdd
  23:	48 c7 c6 80 fe 0c 8c 	mov    $0xffffffff8c0cfe80,%rsi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	90                   	nop
  30:	e9 67 ee ff ff       	jmp    0xffffee9c
  35:	90                   	nop
  36:	0f 0b                	ud2
  38:	90                   	nop
  39:	e9 3a f2 ff ff       	jmp    0xfffff278
  3e:	90                   	nop
  3f:	0f                   	.byte 0xf

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/22 02:30 upstream 4e69c1856bfd 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in vidtv_start_feed
2026/08/21 22:12 upstream 818bebeb63dd 1e72964b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in vidtv_start_feed
2026/08/24 15:01 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 21d6ac051080 23caa175 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in vidtv_start_feed
* Struck through repros no longer work on HEAD.