====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.1.121/4606 is trying to acquire lock: ffff88801cd9f900 (&sb->s_type->i_mutex_key#21){++++}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline] ffff88801cd9f900 (&sb->s_type->i_mutex_key#21){++++}-{3:3}, at: configfs_depend_item_unlocked+0x14f/0x430 fs/configfs/dir.c:1255 but task is already holding lock: ffffffff8cf20cc8 (tpg_instances_lock){+.+.}-{3:3}, at: usbg_make_tpg+0xf5/0x550 drivers/usb/gadget/function/f_tcm.c:1334 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (tpg_instances_lock){+.+.}-{3:3}: __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 usbg_make_tpg+0xf5/0x550 drivers/usb/gadget/function/f_tcm.c:1334 target_fabric_make_tpg+0xa0/0x6d0 drivers/target/target_core_fabric_configfs.c:845 configfs_mkdir+0x511/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x386/0x570 fs/namei.c:4116 do_mkdirat+0x1dd/0x5c0 fs/namei.c:4141 __do_sys_mkdir fs/namei.c:4161 [inline] __se_sys_mkdir fs/namei.c:4159 [inline] __x64_sys_mkdir+0x6a/0x80 fs/namei.c:4159 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #1 (&subsys->su_mutex){+.+.}-{3:3}: __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 configfs_rmdir+0x638/0x980 fs/configfs/dir.c:1556 vfs_rmdir+0x19d/0x410 fs/namei.c:4200 do_rmdir+0x27f/0x710 fs/namei.c:4261 __do_sys_rmdir fs/namei.c:4280 [inline] __se_sys_rmdir fs/namei.c:4278 [inline] __x64_sys_rmdir+0x45/0x50 fs/namei.c:4278 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #0 (&sb->s_type->i_mutex_key#21){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5625 down_write+0x38/0x60 kernel/locking/rwsem.c:1551 inode_lock include/linux/fs.h:793 [inline] configfs_depend_item_unlocked+0x14f/0x430 fs/configfs/dir.c:1255 usbg_make_tpg+0x1dd/0x550 drivers/usb/gadget/function/f_tcm.c:1357 target_fabric_make_tpg+0xa0/0x6d0 drivers/target/target_core_fabric_configfs.c:845 configfs_mkdir+0x511/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x386/0x570 fs/namei.c:4116 do_mkdirat+0x1dd/0x5c0 fs/namei.c:4141 __do_sys_mkdir fs/namei.c:4161 [inline] __se_sys_mkdir fs/namei.c:4159 [inline] __x64_sys_mkdir+0x6a/0x80 fs/namei.c:4159 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 other info that might help us debug this: Chain exists of: &sb->s_type->i_mutex_key#21 --> &subsys->su_mutex --> tpg_instances_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(tpg_instances_lock); lock(&subsys->su_mutex); lock(tpg_instances_lock); lock(&sb->s_type->i_mutex_key#21); *** DEADLOCK *** 4 locks held by syz.1.121/4606: #0: ffff88801d7d8460 (sb_writers#14){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386 #1: ffff888075779aa0 (&sb->s_type->i_mutex_key#7/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:828 [inline] #1: ffff888075779aa0 (&sb->s_type->i_mutex_key#7/1){+.+.}-{3:3}, at: filename_create+0x20b/0x450 fs/namei.c:3886 #2: ffffffff8cc24710 (&subsys->su_mutex){+.+.}-{3:3}, at: configfs_mkdir+0x4b5/0x9e0 fs/configfs/dir.c:1358 #3: ffffffff8cf20cc8 (tpg_instances_lock){+.+.}-{3:3}, at: usbg_make_tpg+0xf5/0x550 drivers/usb/gadget/function/f_tcm.c:1334 stack backtrace: CPU: 0 PID: 4606 Comm: syz.1.121 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5625 down_write+0x38/0x60 kernel/locking/rwsem.c:1551 inode_lock include/linux/fs.h:793 [inline] configfs_depend_item_unlocked+0x14f/0x430 fs/configfs/dir.c:1255 usbg_make_tpg+0x1dd/0x550 drivers/usb/gadget/function/f_tcm.c:1357 target_fabric_make_tpg+0xa0/0x6d0 drivers/target/target_core_fabric_configfs.c:845 configfs_mkdir+0x511/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x386/0x570 fs/namei.c:4116 do_mkdirat+0x1dd/0x5c0 fs/namei.c:4141 __do_sys_mkdir fs/namei.c:4161 [inline] __se_sys_mkdir fs/namei.c:4159 [inline] __x64_sys_mkdir+0x6a/0x80 fs/namei.c:4159 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f1fc702f159 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:00007f1fc5287028 EFLAGS: 00000246 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 00007f1fc72b6fa0 RCX: 00007f1fc702f159 RDX: 0000000000000000 RSI: 00000000000001ff RDI: 0000200000000600 RBP: 00007f1fc70c606b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1fc72b7038 R14: 00007f1fc72b6fa0 R15: 00007ffda2d72108