====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.398/6021 is trying to acquire lock: ffff8880178529d0 (&sb->s_type->i_mutex_key#22){++++}-{3:3}, at: inode_lock include/linux/fs.h:764 [inline] ffff8880178529d0 (&sb->s_type->i_mutex_key#22){++++}-{3:3}, at: configfs_depend_item_unlocked+0x14f/0x430 fs/configfs/dir.c:1255 but task is already holding lock: ffffffff8d805a08 (tpg_instances_lock){+.+.}-{3:3}, at: usbg_make_tpg+0xf5/0x550 drivers/usb/gadget/function/f_tcm.c:1348 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 kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 usbg_make_tpg+0xf5/0x550 drivers/usb/gadget/function/f_tcm.c:1348 target_fabric_make_tpg+0xa0/0x6d0 drivers/target/target_core_fabric_configfs.c:913 configfs_mkdir+0x511/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x386/0x570 fs/namei.c:4157 do_mkdirat+0x1d8/0x440 fs/namei.c:4182 __do_sys_mkdirat fs/namei.c:4197 [inline] __se_sys_mkdirat fs/namei.c:4195 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4195 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (&subsys->su_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 configfs_rmdir+0x638/0x980 fs/configfs/dir.c:1556 vfs_rmdir+0x34e/0x4a0 fs/namei.c:4242 do_rmdir+0x29a/0x5c0 fs/namei.c:4303 __do_sys_rmdir fs/namei.c:4322 [inline] __se_sys_rmdir fs/namei.c:4320 [inline] __x64_sys_rmdir+0x45/0x50 fs/namei.c:4320 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&sb->s_type->i_mutex_key#22){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3830 [inline] __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5678 down_write+0x36/0x60 kernel/locking/rwsem.c:1573 inode_lock include/linux/fs.h:764 [inline] configfs_depend_item_unlocked+0x14f/0x430 fs/configfs/dir.c:1255 usbg_make_tpg+0x1dd/0x550 drivers/usb/gadget/function/f_tcm.c:1371 target_fabric_make_tpg+0xa0/0x6d0 drivers/target/target_core_fabric_configfs.c:913 configfs_mkdir+0x511/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x386/0x570 fs/namei.c:4157 do_mkdirat+0x1d8/0x440 fs/namei.c:4182 __do_sys_mkdirat fs/namei.c:4197 [inline] __se_sys_mkdirat fs/namei.c:4195 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4195 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Chain exists of: &sb->s_type->i_mutex_key#22 --> &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#22); *** DEADLOCK *** 4 locks held by syz.2.398/6021: #0: ffff888018f70460 (sb_writers#16){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402 #1: ffff888054970150 (&sb->s_type->i_mutex_key#7/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:799 [inline] #1: ffff888054970150 (&sb->s_type->i_mutex_key#7/1){+.+.}-{3:3}, at: filename_create+0x20b/0x450 fs/namei.c:3927 #2: ffffffff8d4ea290 (&subsys->su_mutex){+.+.}-{3:3}, at: configfs_mkdir+0x4b5/0x9e0 fs/configfs/dir.c:1358 #3: ffffffff8d805a08 (tpg_instances_lock){+.+.}-{3:3}, at: usbg_make_tpg+0xf5/0x550 drivers/usb/gadget/function/f_tcm.c:1348 stack backtrace: CPU: 1 PID: 6021 Comm: syz.2.398 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3830 [inline] __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5678 down_write+0x36/0x60 kernel/locking/rwsem.c:1573 inode_lock include/linux/fs.h:764 [inline] configfs_depend_item_unlocked+0x14f/0x430 fs/configfs/dir.c:1255 usbg_make_tpg+0x1dd/0x550 drivers/usb/gadget/function/f_tcm.c:1371 target_fabric_make_tpg+0xa0/0x6d0 drivers/target/target_core_fabric_configfs.c:913 configfs_mkdir+0x511/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x386/0x570 fs/namei.c:4157 do_mkdirat+0x1d8/0x440 fs/namei.c:4182 __do_sys_mkdirat fs/namei.c:4197 [inline] __se_sys_mkdirat fs/namei.c:4195 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4195 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f0e7899e159 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:00007f0e797e1028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f0e78c25fa0 RCX: 00007f0e7899e159 RDX: 00000000000001ff RSI: 0000200000000380 RDI: ffffffffffffff9c RBP: 00007f0e78a3506b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0e78c26038 R14: 00007f0e78c25fa0 R15: 00007ffd114c7c68