======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.33/5955 is trying to acquire lock:
ffffffff90480000 (tpg_instances_lock){+.+.}-{4:4}, at: tcm_alloc+0x20/0x440 drivers/usb/gadget/function/f_tcm.c:2734

but task is already holding lock:
ffff888036b28390 (&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:

-> #2 (&gi->lock){+.+.}-{4:4}:
       lock_acquire kernel/locking/lockdep.c:5942 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
       __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+0x695/0x1340 fs/configfs/symlink.c:211
       vfs_symlink fs/namei.c:5794 [inline]
       vfs_symlink+0x178/0x4d0 fs/namei.c:5773
       filename_symlinkat+0x2a6/0x560 fs/namei.c:5819
       __do_sys_symlinkat fs/namei.c:5839 [inline]
       __se_sys_symlinkat fs/namei.c:5834 [inline]
       __x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5834
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&sb->s_type->i_mutex_key#24){++++}-{4:4}:
       lock_acquire kernel/locking/lockdep.c:5942 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
       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:1268
       usbg_make_tpg+0x251/0x610 drivers/usb/gadget/function/f_tcm.c:1692
       target_fabric_make_tpg+0xab/0x8c0 drivers/target/target_core_fabric_configfs.c:947
       configfs_mkdir+0x525/0xd40 fs/configfs/dir.c:1369
       vfs_mkdir+0x364/0x850 fs/namei.c:5410
       filename_mkdirat+0x48b/0x5e0 fs/namei.c:5443
       __do_sys_mkdirat fs/namei.c:5464 [inline]
       __se_sys_mkdirat fs/namei.c:5461 [inline]
       __x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5461
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (tpg_instances_lock){+.+.}-{4:4}:
       check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3209
       check_prevs_add kernel/locking/lockdep.c:3328 [inline]
       validate_chain kernel/locking/lockdep.c:3952 [inline]
       __lock_acquire+0x1528/0x1f40 kernel/locking/lockdep.c:5288
       lock_acquire kernel/locking/lockdep.c:5942 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
       __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:2734
       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+0x695/0x1340 fs/configfs/symlink.c:211
       vfs_symlink fs/namei.c:5794 [inline]
       vfs_symlink+0x178/0x4d0 fs/namei.c:5773
       filename_symlinkat+0x2a6/0x560 fs/namei.c:5819
       __do_sys_symlinkat fs/namei.c:5839 [inline]
       __se_sys_symlinkat fs/namei.c:5834 [inline]
       __x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5834
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       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 ***

locks held by syz.0.33/5955: 3, last CPU#2:
 #0: ffff888024360460 (sb_writers#13){.+.+}-{0:0}, at: filename_create+0x10d/0x400 fs/namei.c:5085
 #1: ffff888056053580 (&sb->s_type->i_mutex_key#24){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #1: ffff888056053580 (&sb->s_type->i_mutex_key#24){++++}-{4:4}, at: configfs_symlink+0x452/0x1340 fs/configfs/symlink.c:201
 #2: ffff888036b28390 (&gi->lock){+.+.}-{4:4}, at: config_usb_cfg_link+0x57/0x3a0 drivers/usb/gadget/configfs.c:439

stack backtrace:
CPU: 2 UID: 0 PID: 5955 Comm: syz.0.33 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+0x178/0x1be kernel/locking/lockdep.c:2087
 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2219
 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3209
 check_prevs_add kernel/locking/lockdep.c:3328 [inline]
 validate_chain kernel/locking/lockdep.c:3952 [inline]
 __lock_acquire+0x1528/0x1f40 kernel/locking/lockdep.c:5288
 lock_acquire kernel/locking/lockdep.c:5942 [inline]
 lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
 __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:2734
 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+0x695/0x1340 fs/configfs/symlink.c:211
 vfs_symlink fs/namei.c:5794 [inline]
 vfs_symlink+0x178/0x4d0 fs/namei.c:5773
 filename_symlinkat+0x2a6/0x560 fs/namei.c:5819
 __do_sys_symlinkat fs/namei.c:5839 [inline]
 __se_sys_symlinkat fs/namei.c:5834 [inline]
 __x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5834
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd157d9e159
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:00007fd158c7a028 EFLAGS: 00000246 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 00007fd158025fa0 RCX: 00007fd157d9e159
RDX: 0000200000000600 RSI: ffffffffffffff9c RDI: 00002000000005c0
RBP: 00007fd157e3506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd158026038 R14: 00007fd158025fa0 R15: 00007ffd601de078
 </TASK>