[syzbot] [kernel?] WARNING in firmware_fallback_sysfs (2)

[syzbot] [kernel?] WARNING in firmware_fallback_sysfs (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    de9c2c66ad8e Linux 6.11-rc2
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14019861980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e8a2eef9745ade09
dashboard link: https://syzkaller.appspot.com/bug?extid=8f06445357a052a92657
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2a5965e13719/disk-de9c2c66.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/52c0d9ae2edc/vmlinux-de9c2c66.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3c8963098f5f/bzImage-de9c2c66.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8f06445357a052a92657@syzkaller.appspotmail.com

usb 1-1: Direct firmware load for v4l-pvrusb2-29xxx-01.fw failed with error -2
usb 1-1: Falling back to sysfs fallback for: v4l-pvrusb2-29xxx-01.fw
------------[ cut here ]------------
WARNING: CPU: 0 PID: 2036 at drivers/base/firmware_loader/fallback.c:148 fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:148 [inline]
WARNING: CPU: 0 PID: 2036 at drivers/base/firmware_loader/fallback.c:148 firmware_fallback_sysfs+0x782/0x9e0 drivers/base/firmware_loader/fallback.c:238
Modules linked in:
CPU: 0 UID: 0 PID: 2036 Comm: pvrusb2-context Not tainted 6.11.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
RIP: 0010:fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:148 [inline]
RIP: 0010:firmware_fallback_sysfs+0x782/0x9e0 drivers/base/firmware_loader/fallback.c:238
Code: 1c 24 e9 4d fc ff ff e8 ec cb 9f fb c6 05 45 f0 0d 0a 01 48 c7 c7 80 83 86 8c e8 f9 1e bf 05 e9 72 fc ff ff e8 cf cb 9f fb 90 <0f> 0b 90 48 89 df 48 c7 c6 60 84 86 8c 4c 89 ea e8 29 85 c1 05 e9
RSP: 0018:ffffc90004daf730 EFLAGS: 00010293
RAX: ffffffff85f3ab21 RBX: ffff88805bb470a8 RCX: ffff8880258a8000
RDX: 0000000000000000 RSI: 00000000fffffff5 RDI: 0000000000000000
RBP: 000000000000003c R08: ffffffff85f3a530 R09: 1ffffffff26e5922
R10: dffffc0000000000 R11: fffffbfff26e5923 R12: 00000000fffffff5
R13: ffffffff8cddfb00 R14: 0000000000000001 R15: 0000000000001770
FS:  0000000000000000(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020bc5000 CR3: 000000000e734000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 _request_firmware+0xcf5/0x12b0 drivers/base/firmware_loader/main.c:914
 request_firmware+0x36/0x50 drivers/base/firmware_loader/main.c:963
 pvr2_locate_firmware+0xb1/0x500 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:1359
 pvr2_upload_firmware1+0x1c6/0x950 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+0x411/0x3d10 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2338
 pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:111 [inline]
 pvr2_context_thread_func+0x4b3/0xb50 drivers/media/usb/pvrusb2/pvrusb2-context.c:158
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>


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Re: [syzbot] [kernel?] WARNING in firmware_fallback_sysfs (2)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    bc35965f6940 Merge tag 'mm-hotfixes-stable-2026-09-03-17-4..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=123d08f9580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8c5c3949d762a91f
dashboard link: https://syzkaller.appspot.com/bug?extid=8f06445357a052a92657
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=125c6125580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8f06445357a052a92657@syzkaller.appspotmail.com

usb 7-1: Falling back to sysfs fallback for: v4l-pvrusb2-160xxx-01.fw
------------[ cut here ]------------
ret
WARNING: drivers/base/firmware_loader/fallback.c:158 at fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:158 [inline], CPU#0: pvrusb2-context/2510
WARNING: drivers/base/firmware_loader/fallback.c:158 at firmware_fallback_sysfs+0x6ef/0xc60 drivers/base/firmware_loader/fallback.c:248, CPU#0: pvrusb2-context/2510
Modules linked in:
CPU: 0 UID: 0 PID: 2510 Comm: pvrusb2-context Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:158 [inline]
RIP: 0010:firmware_fallback_sysfs+0x6ef/0xc60 drivers/base/firmware_loader/fallback.c:248
Code: ff ff e9 2f 42 d0 fa e8 af ab 9b fb e8 6a 31 5f fb 31 ff 89 c3 89 c6 e8 0f a6 9b fb 85 db 0f 84 f5 fa ff ff e8 92 ab 9b fb 90 <0f> 0b 90 48 8b 3c 24 4c 89 e2 48 c7 c6 20 f2 93 8c e8 6b 11 d0 fa
RSP: 0018:ffffc90007d1f8d0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 00000000fffffff5 RCX: 0000000000000000
RDX: ffff88802e7e2580 RSI: ffffffff8670447e RDI: ffff88802e7e2580
RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000fffffff5 R11: 000000000000761b R12: ffffffff8cff0200
R13: ffff888027cff200 R14: 0000000000001770 R15: ffff888027cff210
FS:  0000000000000000(0000) GS:ffff8880d5b60000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f735b1f0980 CR3: 0000000035e42000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 _request_firmware+0xfd7/0x13c0 drivers/base/firmware_loader/main.c:898
 request_firmware+0x35/0x50 drivers/base/firmware_loader/main.c:948
 pvr2_locate_firmware+0x8f/0x330 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:1359
 pvr2_upload_firmware1+0x1ca/0x920 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+0x3e6/0x3710 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2338
 pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:111 [inline]
 pvr2_context_thread_func+0x253/0x920 drivers/media/usb/pvrusb2/pvrusb2-context.c:158
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


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