BUG: unable to handle kernel NULL pointer dereference in dvb_usb_start_feed

Status: moderation: reported on 2026/10/08 22:10
Subsystems: media
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+e1acb3e41d8b7ec78155@syzkaller.appspotmail.com
First crash: 4d16h, last: 4d16h
▶ ▼ ✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision
c59cf013 repro-c 💥 BUG: unable to handle kernel NULL pointer dereference in dvb_usb_start_feed 2026/10/09 05:12 2026/10/09 05:12 2026/10/09 08:12 b2734a59
58bdcf0c repro-c 💥 BUG: unable to handle kernel NULL pointer dereference in dvb_usb_start_feed 2026/10/07 02:52 2026/10/07 02:52 2026/10/07 05:56 f7710056
384c1778 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ BUG: unable to handle kernel NULL pointer dereference in dvb_usb_start_feed 2026/10/06 00:07 2026/10/06 00:07 2026/10/06 00:50 1995e6c7

Sample crash report:
UDC core: USB Raw Gadget: couldn't find an available UDC or it's busy
misc raw-gadget: fail, usb_gadget_register_driver returned -16
usb 6-1: dvb_usb_v2: could not submit urb no. 0 - get them all back
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 80000000271f3067 P4D 80000000271f3067 PUD 0 
Oops: Oops: 0010 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 11786 Comm: syz.0.1565 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc900041d7b58 EFLAGS: 00010246
RAX: 1ffff1100c046e9f RBX: 0000000000000000 RCX: ffff888035b9be80
RDX: 0000000000000002 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900041d7c38 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff888053d44000 R14: ffffffff8c3586b0 R15: ffff888053d449b8
FS:  00007f36bd8e66c0(0000) GS:ffff888125bc2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000003d800000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 dvb_usb_start_feed+0x492/0xc70 drivers/media/usb/dvb-usb-v2/dvb_usb_core.c:299
 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+0x48e/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+0xff/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: 0033:0x7f36bf68e159
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:00007f36bd8e6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f36bf915fa0 RCX: 00007f36bf68e159
RDX: 0000200000000300 RSI: 0000000040146f2c RDI: 0000000000000004
RBP: 00007f36bf72506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f36bf916038 R14: 00007f36bf915fa0 R15: 00007ffffa5c76e8
 </TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc900041d7b58 EFLAGS: 00010246
RAX: 1ffff1100c046e9f RBX: 0000000000000000 RCX: ffff888035b9be80
RDX: 0000000000000002 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900041d7c38 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff888053d44000 R14: ffffffff8c3586b0 R15: ffff888053d449b8
FS:  00007f36bd8e66c0(0000) GS:ffff888125bc2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000003d800000 CR4: 00000000003526f0

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/04 22:04 upstream 6addb4f38557 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in dvb_usb_start_feed
* Struck through repros no longer work on HEAD.