====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz-executor170/5628 is trying to acquire lock: ffff88802456b580 (&sb->s_type->i_mutex_key#17){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] ffff88802456b580 (&sb->s_type->i_mutex_key#17){+.+.}-{4:4}, at: configfs_depend_item_unlocked+0x153/0x420 fs/configfs/dir.c:1259 but task is already holding lock: ffffffff8fe841e0 (tpg_instances_lock){+.+.}-{4:4}, at: usbg_make_tpg+0xf8/0x550 drivers/usb/gadget/function/f_tcm.c:1669 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (tpg_instances_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821 tcm_alloc+0x21/0x2e0 drivers/usb/gadget/function/f_tcm.c:2734 usb_get_function+0x63/0xb0 drivers/usb/gadget/functions.c:61 config_usb_cfg_link+0x148/0x260 drivers/usb/gadget/configfs.c:469 configfs_symlink+0x59a/0x1030 fs/configfs/symlink.c:196 vfs_symlink+0x18b/0x330 fs/namei.c:5796 filename_symlinkat+0x1cd/0x410 fs/namei.c:5821 __do_sys_symlinkat fs/namei.c:5841 [inline] __se_sys_symlinkat+0x4e/0x2b0 fs/namei.c:5836 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&gi->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821 config_usb_cfg_link+0x59/0x260 drivers/usb/gadget/configfs.c:439 configfs_symlink+0x59a/0x1030 fs/configfs/symlink.c:196 vfs_symlink+0x18b/0x330 fs/namei.c:5796 filename_symlinkat+0x1cd/0x410 fs/namei.c:5821 __do_sys_symlinkat fs/namei.c:5841 [inline] __se_sys_symlinkat+0x4e/0x2b0 fs/namei.c:5836 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&sb->s_type->i_mutex_key#17){+.+.}-{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/0x2e50 kernel/locking/lockdep.c:5254 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5908 down_write+0x96/0x200 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+0x1e0/0x550 drivers/usb/gadget/function/f_tcm.c:1692 target_fabric_make_tpg+0xa8/0x6d0 drivers/target/target_core_fabric_configfs.c:947 configfs_mkdir+0x4f6/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x40c/0x620 fs/namei.c:5412 filename_mkdirat+0x285/0x510 fs/namei.c:5445 __do_sys_mkdir fs/namei.c:5472 [inline] __se_sys_mkdir+0x34/0x150 fs/namei.c:5469 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 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: &sb->s_type->i_mutex_key#17 --> &gi->lock --> tpg_instances_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(tpg_instances_lock); lock(&gi->lock); lock(tpg_instances_lock); lock(&sb->s_type->i_mutex_key#17); *** DEADLOCK *** locks held by syz-executor170/5628: 4, last CPU#0: #0: ffff88801d3fa460 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:494 #1: ffff888076bc1dc0 (&sb->s_type->i_mutex_key#8/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1069 [inline] #1: ffff888076bc1dc0 (&sb->s_type->i_mutex_key#8/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2918 [inline] #1: ffff888076bc1dc0 (&sb->s_type->i_mutex_key#8/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2942 [inline] #1: ffff888076bc1dc0 (&sb->s_type->i_mutex_key#8/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:5092 #2: ffffffff8fb4e868 (&subsys->su_mutex){+.+.}-{4:4}, at: configfs_mkdir+0x4b0/0x9e0 fs/configfs/dir.c:1358 #3: ffffffff8fe841e0 (tpg_instances_lock){+.+.}-{4:4}, at: usbg_make_tpg+0xf8/0x550 drivers/usb/gadget/function/f_tcm.c:1669 stack backtrace: CPU: 0 UID: 0 PID: 5628 Comm: syz-executor170 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 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/0x2e50 kernel/locking/lockdep.c:5254 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5908 down_write+0x96/0x200 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+0x1e0/0x550 drivers/usb/gadget/function/f_tcm.c:1692 target_fabric_make_tpg+0xa8/0x6d0 drivers/target/target_core_fabric_configfs.c:947 configfs_mkdir+0x4f6/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x40c/0x620 fs/namei.c:5412 filename_mkdirat+0x285/0x510 fs/namei.c:5445 __do_sys_mkdir fs/namei.c:5472 [inline] __se_sys_mkdir+0x34/0x150 fs/namei.c:5469 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f640df966c9 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:00007ffebb4bb448 EFLAGS: 00000246 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 0000200000000140 RCX: 00007f640df966c9 RDX: 0000000000000000 RSI: 00000000000001ff RDI: 0000200000000c00 RBP: 73666769666e6f63 R08: 0000000000000006 R09: 0000000000000006 R10: 0000000000000006 R11: 0000000000000246 R12: 6769666e6f632f2e R13: 431bde82d7b634db R14: 00007f640e029c40 R15: 0000000000000002