======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz-executor322/5624 is trying to acquire lock:
ffff8880244c5dc0 (&sb->s_type->i_mutex_key#17){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
ffff8880244c5dc0 (&sb->s_type->i_mutex_key#17){+.+.}-{4:4}, at: configfs_depend_item_unlocked+0xf3/0x6a0 fs/configfs/dir.c:1259

but task is already holding lock:
ffff888036e4b918 (&opts->dep_lock){+.+.}-{4:4}, at: usbg_make_tpg+0x1a4/0x620 drivers/usb/gadget/function/f_tcm.c:1678

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&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
       tcm_set_name+0x29/0xb0 drivers/usb/gadget/function/f_tcm.c:2669
       function_make+0x21c/0x3f0 drivers/usb/gadget/configfs.c:636
       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_mkdirat fs/namei.c:5330 [inline]
       __se_sys_mkdirat fs/namei.c:5327 [inline]
       __x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5327
       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 (gadget_subsys.su_mutex){+.+.}-{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
       uvcg_extension_allow_link+0x70/0x280 drivers/usb/gadget/function/uvc_configfs.c:1195
       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

-> #0 (&sb->s_type->i_mutex_key#17){+.+.}-{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
       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_mkdirat fs/namei.c:5330 [inline]
       __se_sys_mkdirat fs/namei.c:5327 [inline]
       __x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5327
       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:
  &sb->s_type->i_mutex_key#17 --> gadget_subsys.su_mutex --> &opts->dep_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&opts->dep_lock);
                               lock(gadget_subsys.su_mutex);
                               lock(&opts->dep_lock);
  lock(&sb->s_type->i_mutex_key#17);

 *** DEADLOCK ***

5 locks held by syz-executor322/5624:
 #0: ffff88801df4c450 (sb_writers#9){.+.+}-{0:0}, at: filename_create+0x10d/0x400 fs/namei.c:4948
 #1: ffff8880792d3580 (&sb->s_type->i_mutex_key#7/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1069 [inline]
 #1: ffff8880792d3580 (&sb->s_type->i_mutex_key#7/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2918 [inline]
 #1: ffff8880792d3580 (&sb->s_type->i_mutex_key#7/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2942 [inline]
 #1: ffff8880792d3580 (&sb->s_type->i_mutex_key#7/1){+.+.}-{4:4}, at: filename_create+0x1c0/0x400 fs/namei.c:4955
 #2: ffffffff8fd87a68 (&subsys->su_mutex){+.+.}-{4:4}, at: configfs_mkdir+0x4b5/0xb70 fs/configfs/dir.c:1358
 #3: ffffffff90252b60 (tpg_instances_lock){+.+.}-{4:4}, at: usbg_make_tpg+0x10b/0x620 drivers/usb/gadget/function/f_tcm.c:1669
 #4: ffff888036e4b918 (&opts->dep_lock){+.+.}-{4:4}, at: usbg_make_tpg+0x1a4/0x620 drivers/usb/gadget/function/f_tcm.c:1678

stack backtrace:
CPU: 0 UID: 0 PID: 5624 Comm: syz-executor322 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
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
 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_mkdirat fs/namei.c:5330 [inline]
 __se_sys_mkdirat fs/namei.c:5327 [inline]
 __x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5327
 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: 0033:0x7fa892310749
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffec68349f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000200000000500 RCX: 00007fa892310749
RDX: 00000000000001ff RSI: 0000200000001000 RDI: 00000000ffffff9c
RBP: 0000200000000000 R08: 0000000000000006 R09: 0000000000000006
R10: 0000000000000006 R11: 0000000000000246 R12: 0000200000000100
R13: 73666769666e6f63 R14: 666e6f63796d2f2e R15: 0000000000000002
 </TASK>