WARNING in firmware_fallback_sysfs (2)

Status: upstream: reported on 2026/08/04 21:17
Reported-by: syzbot+88ad674700b1b2130bf6@syzkaller.appspotmail.com
First crash: 47d, last: 3d07h
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in firmware_fallback_sysfs usb fs -1 syz, C error error 3432 888d 2026d 0/29 auto-obsoleted due to no activity on 2024/06/24 11:12
linux-5.15 WARNING in firmware_fallback_sysfs missing-backport origin:upstream -1 syz, C error 295 47d 1274d 0/3 upstream: reported C repro on 2023/03/26 17:15
linux-6.6 WARNING in firmware_fallback_sysfs origin:lts-only -1 syz, C inconclusive 583 3d05h 460d 0/2 upstream: reported C repro on 2025/06/17 10:18
linux-6.1 WARNING in firmware_fallback_sysfs origin:upstream missing-backport -1 syz, C error 256 59d 1274d 3/3 fixed on 2026/07/24 15:33
upstream WARNING in firmware_fallback_sysfs (2) prio:low kernel -1 C 376 2d18h 772d 0/29 upstream: reported C repro on 2024/08/09 15:45

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 2313 at drivers/base/firmware_loader/fallback.c:154 fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:154 [inline]
WARNING: CPU: 0 PID: 2313 at drivers/base/firmware_loader/fallback.c:154 firmware_fallback_sysfs+0x732/0x960 drivers/base/firmware_loader/fallback.c:244
Modules linked in:
CPU: 0 PID: 2313 Comm: pvrusb2-context Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:154 [inline]
RIP: 0010:firmware_fallback_sysfs+0x732/0x960 drivers/base/firmware_loader/fallback.c:244
Code: 74 66 fc e9 56 fc ff ff e8 4b 74 66 fc c6 05 dd 8d f0 08 01 48 c7 c7 80 14 04 8b e8 48 97 0b 05 e9 79 fc ff ff e8 2e 74 66 fc <0f> 0b 4c 89 f7 48 c7 c6 60 15 04 8b 4c 89 e2 e8 4f 98 0f 05 e9 5b
RSP: 0018:ffffc90006247760 EFLAGS: 00010293
RAX: ffffffff851bbeb2 RBX: dffffc0000000000 RCX: ffff888029ba3c00
RDX: 0000000000000000 RSI: 00000000fffffff5 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffffffff90b0f357 R09: 1ffffffff2161e6a
R10: dffffc0000000000 R11: fffffbfff2161e6b R12: ffffffff8b5fb4c0
R13: 0000000000001770 R14: ffff888074b270a8 R15: 00000000fffffff5
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f698a136e9c CR3: 000000002fc5c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 _request_firmware+0xccb/0x1280 drivers/base/firmware_loader/main.c:884
 request_firmware+0x32/0x50 drivers/base/firmware_loader/main.c:933
 pvr2_locate_firmware+0xb3/0x500 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:1359
 pvr2_upload_firmware1+0x1ba/0x940 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:1426
 pvr2_hdw_setup_low drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2107 [inline]
 pvr2_hdw_setup drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2261 [inline]
 pvr2_hdw_initialize+0x422/0x3c10 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2338
 pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:111 [inline]
 pvr2_context_thread_func+0x4f8/0xbd0 drivers/media/usb/pvrusb2/pvrusb2-context.c:158
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (16):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/17 23:04 linux-6.1.y 1a8763b93150 8d7d05f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/17 22:40 linux-6.1.y e4f7d8be268e 905244d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/17 22:09 linux-6.1.y e4f7d8be268e 905244d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/05 02:00 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/05 01:39 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/05 01:02 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/05 00:40 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/05 00:34 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/05 00:31 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/05 00:20 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/04 23:29 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/04 23:25 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/04 23:14 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/04 23:14 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/04 22:57 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
2026/08/04 21:17 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in firmware_fallback_sysfs
* Struck through repros no longer work on HEAD.