[syzbot] [usb?] possible deadlock in tcm_alloc

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 11028ab62899 Merge tag 'probes-fixes-v7.2-rc5' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10994aea580000
kernel config: https://syzkaller.appspot.com/x/.config?x=145fa60d73086782
dashboard link: https://syzkaller.appspot.com/bug?extid=2799146a53c356f8017d
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

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-11028ab6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e2be78614a29/vmlinux-11028ab6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/301a11d315af/bzImage-11028ab6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+279914...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.239/6703 is trying to acquire lock:
ffffffff90252b60 (tpg_instances_lock){+.+.}-{4:4}, at: tcm_alloc+0x20/0x440 drivers/usb/gadget/function/f_tcm.c:2733

but task is already holding lock:
ffff888058a66390 (&gi->lock){+.+.}-{4:4}, at: config_usb_cfg_link+0x57/0x3a0 drivers/usb/gadget/configfs.c:439

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&gi->lock){+.+.}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821
config_usb_cfg_link+0x57/0x3a0 drivers/usb/gadget/configfs.c:439
configfs_symlink+0x540/0x11f0 fs/configfs/symlink.c:196
vfs_symlink fs/namei.c:5660 [inline]
vfs_symlink+0x178/0x4d0 fs/namei.c:5639
filename_symlinkat+0x2a6/0x560 fs/namei.c:5685
__do_sys_symlinkat fs/namei.c:5705 [inline]
__se_sys_symlinkat fs/namei.c:5700 [inline]
__x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5700
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

-> #2 (&sb->s_type->i_mutex_key#24){++++}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
down_write+0x8b/0x1f0 kernel/locking/rwsem.c:1631
inode_lock include/linux/fs.h:1024 [inline]
configfs_depend_item_unlocked+0xf3/0x6a0 fs/configfs/dir.c:1259
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

-> #1 (&opts->dep_lock){+.+.}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821
usbg_make_tpg+0x1a4/0x620 drivers/usb/gadget/function/f_tcm.c:1678
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

-> #0 (tpg_instances_lock){+.+.}-{4:4}:
check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3165
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821
tcm_alloc+0x20/0x440 drivers/usb/gadget/function/f_tcm.c:2733
usb_get_function+0x5e/0xd0 drivers/usb/gadget/functions.c:61
config_usb_cfg_link+0x1ed/0x3a0 drivers/usb/gadget/configfs.c:469
configfs_symlink+0x540/0x11f0 fs/configfs/symlink.c:196
vfs_symlink fs/namei.c:5660 [inline]
vfs_symlink+0x178/0x4d0 fs/namei.c:5639
filename_symlinkat+0x2a6/0x560 fs/namei.c:5685
__do_sys_symlinkat fs/namei.c:5705 [inline]
__se_sys_symlinkat fs/namei.c:5700 [inline]
__x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5700
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

other info that might help us debug this:

Chain exists of:
tpg_instances_lock --> &sb->s_type->i_mutex_key#24 --> &gi->lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&gi->lock);
lock(&sb->s_type->i_mutex_key#24);
lock(&gi->lock);
lock(tpg_instances_lock);

*** DEADLOCK ***

3 locks held by syz.0.239/6703:
#0: ffff888024522450 (sb_writers#13){.+.+}-{0:0}, at: filename_create+0x10d/0x400 fs/namei.c:4948
#1: ffff888057d20ac0 (&sb->s_type->i_mutex_key#24){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#1: ffff888057d20ac0 (&sb->s_type->i_mutex_key#24){++++}-{4:4}, at: configfs_symlink+0x3c0/0x11f0 fs/configfs/symlink.c:186
#2: ffff888058a66390 (&gi->lock){+.+.}-{4:4}, at: config_usb_cfg_link+0x57/0x3a0 drivers/usb/gadget/configfs.c:439

stack backtrace:
CPU: 2 UID: 0 PID: 6703 Comm: syz.0.239 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
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043
check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175
check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3165
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821
tcm_alloc+0x20/0x440 drivers/usb/gadget/function/f_tcm.c:2733
usb_get_function+0x5e/0xd0 drivers/usb/gadget/functions.c:61
config_usb_cfg_link+0x1ed/0x3a0 drivers/usb/gadget/configfs.c:469
configfs_symlink+0x540/0x11f0 fs/configfs/symlink.c:196
vfs_symlink fs/namei.c:5660 [inline]
vfs_symlink+0x178/0x4d0 fs/namei.c:5639
filename_symlinkat+0x2a6/0x560 fs/namei.c:5685
__do_sys_symlinkat fs/namei.c:5705 [inline]
__se_sys_symlinkat fs/namei.c:5700 [inline]
__x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5700
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: 0033:0x7f358b59df99
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:00007f358c541028 EFLAGS: 00000246 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 00007f358b825fa0 RCX: 00007f358b59df99
RDX: 0000200000000400 RSI: ffffffffffffff9c RDI: 0000200000000300
RBP: 00007f358b634ec4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f358b826038 R14: 00007f358b825fa0 R15: 00007ffdf9fc7e88
</TASK>


---
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