WARNING in media_create_pad_link (2)

Status: auto-obsoleted due to no activity on 2026/07/09 20:59
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+fdb1feaa214f91bff2d0@syzkaller.appspotmail.com
First crash: 136d, last: 121d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2026/03/18 linux-5.15.y (ToT) 91d48252ad4b C [report] WARNING in media_create_pad_link
2026/03/18 upstream (ToT) 8a30aeb0d1b4 C Didn't crash
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in media_create_pad_link (2) usb media -1 syz, C error done 11 295d 498d 29/29 fixed on 2025/11/14 14:05
linux-5.15 WARNING in media_create_pad_link origin:upstream -1 syz, C error 7 596d 1229d 0/3 auto-obsoleted due to no activity on 2025/03/22 03:16
linux-6.1 WARNING in media_create_pad_link origin:upstream -1 syz, C error 2 697d 1228d 3/3 fixed on 2024/12/14 20:01
upstream WARNING in media_create_pad_link usb media -1 syz, C done done 104 616d 2268d 28/29 fixed on 2024/12/16 09:50
linux-6.1 WARNING in media_create_pad_link (2) origin:lts-only -1 syz, C inconclusive 16 105d 136d 0/3 upstream: reported C repro on 2026/03/17 03:30
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/06/03 07:15 23m retest repro linux-5.15.y OK log
▶ ▼ Fix bisection attempts (3)
Created Duration User Patch Repo Result
2026/05/20 14:08 18m fix candidate upstream error job log
2026/04/20 13:23 22m fix candidate upstream error job log
2026/03/19 08:04 34m fix candidate upstream error job log

Sample crash report:
usb 2-1: Found UVC 7.ff device syz (174f:5212)
uvcvideo 2-1:6.220: Entity type for entity Output 4 was not initialized!
------------[ cut here ]------------
WARNING: CPU: 0 PID: 4230 at drivers/media/mc/mc-entity.c:667 media_create_pad_link+0x98a/0xae0 drivers/media/mc/mc-entity.c:667
Modules linked in:
CPU: 0 PID: 4230 Comm: kworker/0:5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: usb_hub_wq hub_event
RIP: 0010:media_create_pad_link+0x98a/0xae0 drivers/media/mc/mc-entity.c:667
Code: 01 00 00 66 ff 03 31 c0 48 83 c4 50 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 04 23 06 fb 0f 0b b8 ea ff ff ff eb e3 e8 f6 22 06 fb <0f> 0b b8 ea ff ff ff eb d5 e8 e8 22 06 fb 0f 0b b8 ea ff ff ff eb
RSP: 0018:ffffc9000322eaa0 EFLAGS: 00010287
RAX: ffffffff8672fe1a RBX: 0000000000000002 RCX: 0000000000100000
RDX: ffffc90013338000 RSI: 00000000000277ce RDI: 00000000000277cf
RBP: 0000000000000000 R08: 0000000000000003 R09: 1ffff1100c0a1297
R10: dffffc0000000000 R11: ffffed100c0a1298 R12: ffff88807ee90880
R13: ffff8880734b1080 R14: 0000000000000000 R15: ffff8880734b11c0
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3a1ff7 CR3: 000000007ebe2000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 uvc_mc_create_links drivers/media/usb/uvc/uvc_entity.c:50 [inline]
 uvc_mc_register_entities+0x6be/0x930 drivers/media/usb/uvc/uvc_entity.c:151
 uvc_register_chains+0x3cf/0x4b0 drivers/media/usb/uvc/uvc_driver.c:2360
 uvc_probe+0xa356/0xac00 drivers/media/usb/uvc/uvc_driver.c:2505
 usb_probe_interface+0x5c5/0xb20 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x284/0xc80 drivers/base/dd.c:595
 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
 __device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a8/0x480 drivers/base/dd.c:979
 bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
 device_add+0xa00/0xfb0 drivers/base/core.c:3412
 usb_set_configuration+0x1991/0x1fd0 drivers/usb/core/message.c:2165
 usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
 usb_probe_device+0x139/0x270 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x284/0xc80 drivers/base/dd.c:595
 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
 __device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a8/0x480 drivers/base/dd.c:979
 bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
 device_add+0xa00/0xfb0 drivers/base/core.c:3412
 usb_new_device+0xd65/0x1660 drivers/usb/core/hub.c:2632
 hub_port_connect drivers/usb/core/hub.c:5497 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5637 [inline]
 port_event drivers/usb/core/hub.c:5799 [inline]
 hub_event+0x2e4a/0x55e0 drivers/usb/core/hub.c:5881
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/31 20:59 linux-5.15.y 91d48252ad4b aeea1c72 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in media_create_pad_link
2026/03/18 10:10 linux-5.15.y 91d48252ad4b c8810548 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in media_create_pad_link
2026/03/17 02:24 linux-5.15.y 91d48252ad4b 0737c18f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in media_create_pad_link
2026/03/17 02:24 linux-5.15.y 91d48252ad4b 0737c18f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in media_create_pad_link
* Struck through repros no longer work on HEAD.