[moderation] [fs?] general protection fault in configfs_depend_item_unlocked

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4235cb24ec1e Merge tag 'vfs-7.2-rc5.fixes' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=119ec6b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b7079b368dcec295
dashboard link: https://syzkaller.appspot.com/bug?extid=d0e98cbb85bec373bb33
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
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: https://storage.googleapis.com/syzbot-assets/efc7b2f0cdd3/disk-4235cb24.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bd4a09c82e14/vmlinux-4235cb24.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7a0b50818a22/bzImage-4235cb24.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d0e98c...@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067]
CPU: 0 UID: 0 PID: 13143 Comm: syz.6.1876 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:configfs_depend_item_unlocked+0x24a/0x6a0 fs/configfs/dir.c:1246
Code: be fc 08 c7 44 24 1c fe ff ff ff e9 a6 02 00 00 e8 9b 57 4a ff 48 8d 7d 60 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 1d 04 00 00 48 bb 00 00 00 00 00 fc ff df 4c 8b
RSP: 0018:ffffc90004a27b28 EFLAGS: 00010216
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90020802000
RDX: 000000000000000c RSI: ffffffff82bfe785 RDI: 0000000000000060
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88807c68ec00 R14: ffff88807c68ec00 R15: ffff88807c68ecb8
FS: 00007f53b48bd6c0(0000) GS:ffff888123dde000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2da18ff8 CR3: 0000000076580000 CR4: 0000000000350ef0
Call Trace:
<TASK>
usbg_make_tpg+0x261/0x620 drivers/usb/gadget/function/f_tcm.c:1686
target_fabric_make_tpg+0xab/0x8c0 drivers/target/target_core_fabric_configfs.c:939
configfs_mkdir+0x51e/0xb70 fs/configfs/dir.c:1360
vfs_mkdir+0x361/0x850 fs/namei.c:5276
filename_mkdirat+0x48b/0x5e0 fs/namei.c:5309
__do_sys_mkdir fs/namei.c:5336 [inline]
__se_sys_mkdir fs/namei.c:5333 [inline]
__x64_sys_mkdir+0x6b/0x90 fs/namei.c:5333
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f53b399de99
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:00007f53b48bd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00007f53b3c26090 RCX: 00007f53b399de99
RDX: 0000000000000000 RSI: 00000000000001ff RDI: 0000200000000600
RBP: 00007f53b3a33eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f53b3c26128 R14: 00007f53b3c26090 R15: 00007fffd5a8f168
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:configfs_depend_item_unlocked+0x24a/0x6a0 fs/configfs/dir.c:1246
Code: be fc 08 c7 44 24 1c fe ff ff ff e9 a6 02 00 00 e8 9b 57 4a ff 48 8d 7d 60 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 1d 04 00 00 48 bb 00 00 00 00 00 fc ff df 4c 8b
RSP: 0018:ffffc90004a27b28 EFLAGS: 00010216
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90020802000
RDX: 000000000000000c RSI: ffffffff82bfe785 RDI: 0000000000000060
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88807c68ec00 R14: ffff88807c68ec00 R15: ffff88807c68ecb8
FS: 00007f53b48bd6c0(0000) GS:ffff888123dde000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055cd41293268 CR3: 0000000076580000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess), 3 bytes skipped:
0: c7 44 24 1c fe ff ff movl $0xfffffffe,0x1c(%rsp)
7: ff
8: e9 a6 02 00 00 jmp 0x2b3
d: e8 9b 57 4a ff call 0xff4a57ad
12: 48 8d 7d 60 lea 0x60(%rbp),%rdi
16: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
1d: fc ff df
20: 48 89 fa mov %rdi,%rdx
23: 48 c1 ea 03 shr $0x3,%rdx
* 27: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2b: 0f 85 1d 04 00 00 jne 0x44e
31: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx
38: fc ff df
3b: 4c rex.WR
3c: 8b .byte 0x8b


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