WARNING in firmware_fallback_sysfs (2)

Status: upstream: reported on 2026/08/04 21:17
Reported-by: syzbot+88ad674700b1b2130bf6@syzkaller.appspotmail.com
First crash: 2d03h, last: 1d22h
▶ ▼ 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 843d 1981d 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 1d23h 1229d 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 580 1d22h 415d 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 13d 1229d 3/3 fixed on 2026/07/24 15:33
upstream WARNING in firmware_fallback_sysfs (2) prio:low kernel -1 328 2d01h 727d 0/29 upstream: reported on 2024/08/09 15:45

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 4439 at drivers/base/firmware_loader/fallback.c:144 fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:144 [inline]
WARNING: CPU: 1 PID: 4439 at drivers/base/firmware_loader/fallback.c:144 firmware_fallback_sysfs+0x71e/0x950 drivers/base/firmware_loader/fallback.c:234
Modules linked in:
CPU: 1 PID: 4439 Comm: cxacru 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:144 [inline]
RIP: 0010:firmware_fallback_sysfs+0x71e/0x950 drivers/base/firmware_loader/fallback.c:234
Code: df e8 36 6a f9 ff 45 89 e7 eb bc e8 bc 01 67 fc c6 05 14 75 f1 08 01 48 c7 c7 20 06 04 8b e8 79 b9 09 05 eb a7 e8 a2 01 67 fc <0f> 0b 4c 89 f7 48 c7 c6 00 07 04 8b 4c 89 e2 e8 83 ba 0d 05 eb 8c
RSP: 0018:ffffc90005037ae0 EFLAGS: 00010293
RAX: ffffffff851b2c7e RBX: dffffc0000000000 RCX: ffff88801a36bc00
RDX: 0000000000000000 RSI: 00000000fffffff5 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffffffff8c9da6e3 R09: 1ffffffff193b4dc
R10: dffffc0000000000 R11: fffffbfff193b4dd R12: ffffc90005037d40
R13: 0000000000001770 R14: ffff888074acd030 R15: 00000000fffffff5
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbbe797c000 CR3: 00000000276d6000 CR4: 00000000003506e0
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
 cxacru_find_firmware+0x101/0x230 drivers/usb/atm/cxacru.c:994
 cxacru_heavy_init+0x17a/0xc40 drivers/usb/atm/cxacru.c:1016
 usbatm_do_heavy_init+0x8a/0x110 drivers/usb/atm/usbatm.c:963
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (13):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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.