====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.2523/12838 is trying to acquire lock: ffffffff8ddf6d10 (gadget_subsys.su_mutex){+.+.}-{3:3}, at: uvcg_streaming_header_allow_link+0x71/0x4a0 drivers/usb/gadget/function/uvc_configfs.c:1747 but task is already holding lock: ffff8880772ed090 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline] ffff8880772ed090 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: configfs_symlink+0x47a/0xfe0 fs/configfs/symlink.c:192 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&sb->s_type->i_mutex_key#20){++++}-{3:3}: down_write+0x97/0x200 kernel/locking/rwsem.c:1573 inode_lock include/linux/fs.h:804 [inline] configfs_depend_item_unlocked+0x157/0x430 fs/configfs/dir.c:1255 usbg_make_tpg+0x1f7/0x580 drivers/usb/gadget/function/f_tcm.c:1341 target_fabric_make_tpg+0xa4/0x6d0 drivers/target/target_core_fabric_configfs.c:939 configfs_mkdir+0x515/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x2a5/0x470 fs/namei.c:4125 do_mkdirat+0x1dc/0x450 fs/namei.c:4148 __do_sys_mkdir fs/namei.c:4168 [inline] __se_sys_mkdir fs/namei.c:4166 [inline] __x64_sys_mkdir+0x6e/0x80 fs/namei.c:4166 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (&opts->dep_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x135/0xc80 kernel/locking/mutex.c:747 tcm_set_name+0x2a/0x90 drivers/usb/gadget/function/f_tcm.c:2188 function_make+0x199/0x350 drivers/usb/gadget/configfs.c:635 configfs_mkdir+0x515/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x2a5/0x470 fs/namei.c:4125 do_mkdirat+0x1dc/0x450 fs/namei.c:4148 __do_sys_mkdir fs/namei.c:4168 [inline] __se_sys_mkdir fs/namei.c:4166 [inline] __x64_sys_mkdir+0x6e/0x80 fs/namei.c:4166 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (gadget_subsys.su_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x37ef/0x7d80 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x135/0xc80 kernel/locking/mutex.c:747 uvcg_streaming_header_allow_link+0x71/0x4a0 drivers/usb/gadget/function/uvc_configfs.c:1747 configfs_symlink+0x5a5/0xfe0 fs/configfs/symlink.c:202 vfs_symlink+0x138/0x2b0 fs/namei.c:4485 do_symlinkat+0x1ba/0x400 fs/namei.c:4511 __do_sys_symlinkat fs/namei.c:4527 [inline] __se_sys_symlinkat fs/namei.c:4524 [inline] __x64_sys_symlinkat+0x99/0xb0 fs/namei.c:4524 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Chain exists of: gadget_subsys.su_mutex --> &opts->dep_lock --> &sb->s_type->i_mutex_key#20 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#20); lock(&opts->dep_lock); lock(&sb->s_type->i_mutex_key#20); lock(gadget_subsys.su_mutex); *** DEADLOCK *** 2 locks held by syz.0.2523/12838: #0: ffff888142e46418 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412 #1: ffff8880772ed090 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline] #1: ffff8880772ed090 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: configfs_symlink+0x47a/0xfe0 fs/configfs/symlink.c:192 stack backtrace: CPU: 0 PID: 12838 Comm: syz.0.2523 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 check_noncircular+0x2fc/0x400 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x37ef/0x7d80 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x135/0xc80 kernel/locking/mutex.c:747 uvcg_streaming_header_allow_link+0x71/0x4a0 drivers/usb/gadget/function/uvc_configfs.c:1747 configfs_symlink+0x5a5/0xfe0 fs/configfs/symlink.c:202 vfs_symlink+0x138/0x2b0 fs/namei.c:4485 do_symlinkat+0x1ba/0x400 fs/namei.c:4511 __do_sys_symlinkat fs/namei.c:4527 [inline] __se_sys_symlinkat fs/namei.c:4524 [inline] __x64_sys_symlinkat+0x99/0xb0 fs/namei.c:4524 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f126099e019 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:00007f1261902028 EFLAGS: 00000246 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 00007f1260c25fa0 RCX: 00007f126099e019 RDX: 0000200000001600 RSI: ffffffffffffff9c RDI: 0000200000001500 RBP: 00007f1260a3500c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1260c26038 R14: 00007f1260c25fa0 R15: 00007ffc3a91b258 configfs-gadget.g1 gadget.32: uvc: uvc_function_bind() udc usbip-vudc.0: failed to start g1: -19 UDC core: g1: couldn't find an available UDC or it's busy