====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.6.2009/13648 is trying to acquire lock: ffffffff8d7b2f90 (gadget_subsys.su_mutex){+.+.}-{3:3}, at: uvcg_streaming_header_allow_link+0x6d/0x4a0 drivers/usb/gadget/function/uvc_configfs.c:884 but task is already holding lock: ffff888055635080 (&sb->s_type->i_mutex_key#26){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] ffff888055635080 (&sb->s_type->i_mutex_key#26){++++}-{3:3}, at: configfs_symlink+0x47b/0x13c0 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#26){++++}-{3:3}: down_write+0x36/0x60 kernel/locking/rwsem.c:1573 inode_lock include/linux/fs.h:758 [inline] configfs_depend_item_unlocked+0x14f/0x430 fs/configfs/dir.c:1255 usbg_make_tpg+0x1f3/0x580 drivers/usb/gadget/function/f_tcm.c:1365 target_fabric_make_tpg+0xa0/0x6d0 drivers/target/target_core_fabric_configfs.c:905 configfs_mkdir+0x511/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x386/0x570 fs/namei.c:4114 do_mkdirat+0x1d8/0x440 fs/namei.c:4139 __do_sys_mkdir fs/namei.c:4159 [inline] __se_sys_mkdir fs/namei.c:4157 [inline] __x64_sys_mkdir+0x6a/0x80 fs/namei.c:4157 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 (&opts->dep_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 tcm_set_name+0x26/0x90 drivers/usb/gadget/function/f_tcm.c:2219 function_make+0x195/0x350 drivers/usb/gadget/configfs.c:625 configfs_mkdir+0x511/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x386/0x570 fs/namei.c:4114 do_mkdirat+0x1d8/0x440 fs/namei.c:4139 __do_sys_mkdir fs/namei.c:4159 [inline] __se_sys_mkdir fs/namei.c:4157 [inline] __x64_sys_mkdir+0x6a/0x80 fs/namei.c:4157 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 (gadget_subsys.su_mutex){+.+.}-{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:5676 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 uvcg_streaming_header_allow_link+0x6d/0x4a0 drivers/usb/gadget/function/uvc_configfs.c:884 configfs_symlink+0x5a4/0x13c0 fs/configfs/symlink.c:202 vfs_symlink+0x245/0x3d0 fs/namei.c:4479 do_symlinkat+0x1b6/0x400 fs/namei.c:4508 __do_sys_symlinkat fs/namei.c:4525 [inline] __se_sys_symlinkat fs/namei.c:4522 [inline] __x64_sys_symlinkat+0x95/0xa0 fs/namei.c:4522 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: gadget_subsys.su_mutex --> &opts->dep_lock --> &sb->s_type->i_mutex_key#26 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#26); lock(&opts->dep_lock); lock(&sb->s_type->i_mutex_key#26); lock(gadget_subsys.su_mutex); *** DEADLOCK *** 2 locks held by syz.6.2009/13648: #0: ffff88801a7b0460 (sb_writers#19){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402 #1: ffff888055635080 (&sb->s_type->i_mutex_key#26){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff888055635080 (&sb->s_type->i_mutex_key#26){++++}-{3:3}, at: configfs_symlink+0x47b/0x13c0 fs/configfs/symlink.c:192 stack backtrace: CPU: 1 PID: 13648 Comm: syz.6.2009 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:5676 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 uvcg_streaming_header_allow_link+0x6d/0x4a0 drivers/usb/gadget/function/uvc_configfs.c:884 configfs_symlink+0x5a4/0x13c0 fs/configfs/symlink.c:202 vfs_symlink+0x245/0x3d0 fs/namei.c:4479 do_symlinkat+0x1b6/0x400 fs/namei.c:4508 __do_sys_symlinkat fs/namei.c:4525 [inline] __se_sys_symlinkat fs/namei.c:4522 [inline] __x64_sys_symlinkat+0x95/0xa0 fs/namei.c:4522 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: 0033:0x7f4b0a99e019 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:00007f4b0b857028 EFLAGS: 00000246 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 00007f4b0ac25fa0 RCX: 00007f4b0a99e019 RDX: 0000200000001600 RSI: ffffffffffffff9c RDI: 0000200000001500 RBP: 00007f4b0aa3500c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4b0ac26038 R14: 00007f4b0ac25fa0 R15: 00007fffeae9a3e8