[moderation] [fs?] VFS: Close: file count is zero (use-after-free) (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: bd1dde877520 Merge tag 'vfs-7.2-rc6.fixes' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1120ec9e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c05be6c9b0d36cb9
dashboard link: https://syzkaller.appspot.com/bug?extid=f95090e892d74b08ac6f
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
CC: [a.hin...@kernel.org lei...@debian.org linux-...@vger.kernel.org linux-...@vger.kernel.org]

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-bd1dde87.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/db8e24aa4aad/vmlinux-bd1dde87.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d6a8adc75a55/bzImage-bd1dde87.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f95090...@syzkaller.appspotmail.com

slab filp start ffff88803f1a7c40 pointer offset 0 size 352
VFS: Close: file count is 0 (f_op=snd_ctl_f_ops)
------------[ cut here ]------------
kernel BUG at fs/open.c:1466!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5327 Comm: syz.0.0 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:filp_flush+0x184/0x190 fs/open.c:1464
Code: 48 83 c3 48 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 dc 13 ee ff 48 8b 33 48 c7 c7 80 8c fe 8b e8 ed 7b df fe 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000e2b76b8 EFLAGS: 00010246
RAX: 0000000000000030 RBX: ffff88803f1a7c88 RCX: 3851772b82498100
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc9000e2b77d8 R08: ffff88801fc24713 R09: 1ffff11003f848e2
R10: dffffc0000000000 R11: ffffed1003f848e3 R12: dffffc0000000000
R13: ffff888012d10528 R14: 0000000000000000 R15: 0000000000000003
FS: 00007f3b28a4d6c0(0000) GS:ffff88808c540000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3b27dd1b00 CR3: 000000001fb3a000 CR4: 0000000000352ef0
Call Trace:
<TASK>
filp_close+0x1d/0x40 fs/open.c:1484
gaudio_close_snd_dev drivers/usb/gadget/function/u_uac1_legacy.c:263 [inline]
gaudio_cleanup+0x54/0xf0 drivers/usb/gadget/function/u_uac1_legacy.c:305
f_audio_bind+0x4a0/0x630 drivers/usb/gadget/function/f_uac1_legacy.c:792
usb_add_function+0x2e1/0x9f0 drivers/usb/gadget/composite.c:333
configfs_composite_bind+0xde0/0x1410 drivers/usb/gadget/configfs.c:1802
gadget_bind_driver+0x2ca/0x9e0 drivers/usb/gadget/udc/core.c:1662
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x254/0xae0 drivers/base/dd.c:706
__driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
__driver_attach+0x339/0x600 drivers/base/dd.c:1292
bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:383
bus_add_driver+0x345/0x670 drivers/base/bus.c:763
driver_register+0x23a/0x320 drivers/base/driver.c:174
usb_gadget_register_driver_owner+0xf9/0x270 drivers/usb/gadget/udc/core.c:1752
gadget_dev_desc_UDC_store+0x1c9/0x2f0 drivers/usb/gadget/configfs.c:300
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0x337/0x430 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x612/0xba0 fs/read_write.c:687
ksys_write+0x150/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3b27b9e019
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:00007f3b28a4cfe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f3b27e26090 RCX: 00007f3b27b9e019
RDX: 000000000000000c RSI: 0000200000000400 RDI: 0000000000000003
RBP: 00007f3b27c3500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3b27e26128 R14: 00007f3b27e26090 R15: 00007ffef9c9dc58
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:filp_flush+0x184/0x190 fs/open.c:1464
Code: 48 83 c3 48 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 dc 13 ee ff 48 8b 33 48 c7 c7 80 8c fe 8b e8 ed 7b df fe 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000e2b76b8 EFLAGS: 00010246
RAX: 0000000000000030 RBX: ffff88803f1a7c88 RCX: 3851772b82498100
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc9000e2b77d8 R08: ffff88801fc24713 R09: 1ffff11003f848e2
R10: dffffc0000000000 R11: ffffed1003f848e3 R12: dffffc0000000000
R13: ffff888012d10528 R14: 0000000000000000 R15: 0000000000000003
FS: 00007f3b28a4d6c0(0000) GS:ffff88808c540000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3b27d5bab0 CR3: 000000001fb3a000 CR4: 0000000000352ef0


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