====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.19/5976 is trying to acquire lock: ffff888023170178 (&sb->s_type->i_mutex_key#23){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] ffff888023170178 (&sb->s_type->i_mutex_key#23){++++}-{4:4}, at: configfs_depend_item_unlocked+0x153/0x420 fs/configfs/dir.c:1259 but task is already holding lock: ffff888044e56d10 (&opts->dep_lock){+.+.}-{4:4}, at: usbg_make_tpg+0x147/0x590 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}: __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 tcm_set_name+0x2b/0xd0 drivers/usb/gadget/function/f_tcm.c:2669 function_make+0x1a8/0x360 drivers/usb/gadget/configfs.c:636 configfs_mkdir+0x4f6/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x408/0x620 fs/namei.c:5270 filename_mkdirat+0x289/0x520 fs/namei.c:5303 __do_sys_mkdirat fs/namei.c:5324 [inline] __se_sys_mkdirat+0x35/0x150 fs/namei.c:5321 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x17b/0x530 arch/x86/entry/syscall_64.c:85 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (gadget_subsys.su_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 configfs_rmdir+0x5f0/0x950 fs/configfs/dir.c:1556 vfs_rmdir+0x3e9/0x6b0 fs/namei.c:5375 filename_rmdir+0x292/0x520 fs/namei.c:5432 __do_sys_unlinkat fs/namei.c:5607 [inline] __se_sys_unlinkat+0x71/0x1a0 fs/namei.c:5600 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x17b/0x530 arch/x86/entry/syscall_64.c:85 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&sb->s_type->i_mutex_key#23){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3181 [inline] check_prevs_add kernel/locking/lockdep.c:3300 [inline] validate_chain kernel/locking/lockdep.c:3924 [inline] __lock_acquire+0x15ff/0x2e40 kernel/locking/lockdep.c:5254 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5906 down_write+0x3a/0x50 kernel/locking/rwsem.c:1631 inode_lock include/linux/fs.h:1024 [inline] configfs_depend_item_unlocked+0x153/0x420 fs/configfs/dir.c:1259 usbg_make_tpg+0x1f6/0x590 drivers/usb/gadget/function/f_tcm.c:1686 target_fabric_make_tpg+0xa8/0x6d0 drivers/target/target_core_fabric_configfs.c:939 configfs_mkdir+0x4f6/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x408/0x620 fs/namei.c:5270 filename_mkdirat+0x289/0x520 fs/namei.c:5303 __do_sys_mkdirat fs/namei.c:5324 [inline] __se_sys_mkdirat+0x35/0x150 fs/namei.c:5321 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x17b/0x530 arch/x86/entry/syscall_64.c:85 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &sb->s_type->i_mutex_key#23 --> 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#23); *** DEADLOCK *** locks held by syz.2.19/5976: 5, last CPU#1: #0: ffff88801c794510 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:494 #1: ffff888040dadd60 (&sb->s_type->i_mutex_key#7/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1069 [inline] #1: ffff888040dadd60 (&sb->s_type->i_mutex_key#7/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2918 [inline] #1: ffff888040dadd60 (&sb->s_type->i_mutex_key#7/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2942 [inline] #1: ffff888040dadd60 (&sb->s_type->i_mutex_key#7/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:4949 #2: ffffffff8eea86e0 (&subsys->su_mutex){+.+.}-{4:4}, at: configfs_mkdir+0x4b0/0x9e0 fs/configfs/dir.c:1358 #3: ffffffff8f1defd8 (tpg_instances_lock){+.+.}-{4:4}, at: usbg_make_tpg+0xf7/0x590 drivers/usb/gadget/function/f_tcm.c:1669 #4: ffff888044e56d10 (&opts->dep_lock){+.+.}-{4:4}, at: usbg_make_tpg+0x147/0x590 drivers/usb/gadget/function/f_tcm.c:1678 stack backtrace: CPU: 1 UID: 0 PID: 5976 Comm: syz.2.19 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2059 check_noncircular+0x12f/0x150 kernel/locking/lockdep.c:2191 check_prev_add kernel/locking/lockdep.c:3181 [inline] check_prevs_add kernel/locking/lockdep.c:3300 [inline] validate_chain kernel/locking/lockdep.c:3924 [inline] __lock_acquire+0x15ff/0x2e40 kernel/locking/lockdep.c:5254 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5906 down_write+0x3a/0x50 kernel/locking/rwsem.c:1631 inode_lock include/linux/fs.h:1024 [inline] configfs_depend_item_unlocked+0x153/0x420 fs/configfs/dir.c:1259 usbg_make_tpg+0x1f6/0x590 drivers/usb/gadget/function/f_tcm.c:1686 target_fabric_make_tpg+0xa8/0x6d0 drivers/target/target_core_fabric_configfs.c:939 configfs_mkdir+0x4f6/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x408/0x620 fs/namei.c:5270 filename_mkdirat+0x289/0x520 fs/namei.c:5303 __do_sys_mkdirat fs/namei.c:5324 [inline] __se_sys_mkdirat+0x35/0x150 fs/namei.c:5321 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x17b/0x530 arch/x86/entry/syscall_64.c:85 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5226e2de99 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:00007f522648e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f52270b5fa0 RCX: 00007f5226e2de99 RDX: 00000000000001ff RSI: 0000200000001000 RDI: ffffffffffffff9c RBP: 00007f5226ec3eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f52270b6038 R14: 00007f52270b5fa0 R15: 00007ffc84a12a28