====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.5.1016/10280 is trying to acquire lock: ffff0000c14c8f80 (&sb->s_type->i_mutex_key#30){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] ffff0000c14c8f80 (&sb->s_type->i_mutex_key#30){++++}-{4:4}, at: configfs_depend_item_unlocked+0x154/0x344 fs/configfs/dir.c:1268 but task is already holding lock: ffff80008a46cd60 (tpg_instances_lock){+.+.}-{4:4}, at: usbg_make_tpg+0x14c/0x4a0 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+0x164/0x1078 kernel/locking/mutex.c:821 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874 tcm_alloc+0x30/0x2e8 drivers/usb/gadget/function/f_tcm.c:2734 usb_get_function+0x64/0xb0 drivers/usb/gadget/functions.c:61 config_usb_cfg_link+0x158/0x224 drivers/usb/gadget/configfs.c:469 configfs_symlink+0x5ec/0xfb4 fs/configfs/symlink.c:211 vfs_symlink+0x16c/0x290 fs/namei.c:5823 filename_symlinkat+0x18c/0x328 fs/namei.c:5848 __do_sys_symlinkat fs/namei.c:5868 [inline] __se_sys_symlinkat fs/namei.c:5863 [inline] __arm64_sys_symlinkat+0xb0/0xdc fs/namei.c:5863 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606 -> #1 (&gi->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x164/0x1078 kernel/locking/mutex.c:821 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874 config_usb_cfg_link+0x5c/0x224 drivers/usb/gadget/configfs.c:439 configfs_symlink+0x5ec/0xfb4 fs/configfs/symlink.c:211 vfs_symlink+0x16c/0x290 fs/namei.c:5823 filename_symlinkat+0x18c/0x328 fs/namei.c:5848 __do_sys_symlinkat fs/namei.c:5868 [inline] __se_sys_symlinkat fs/namei.c:5863 [inline] __arm64_sys_symlinkat+0xb0/0xdc fs/namei.c:5863 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606 -> #0 (&sb->s_type->i_mutex_key#30){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x1660/0x2b08 kernel/locking/lockdep.c:5288 lock_acquire+0x13c/0x320 kernel/locking/lockdep.c:5942 down_write+0xac/0x2a8 kernel/locking/rwsem.c:1631 inode_lock include/linux/fs.h:1024 [inline] configfs_depend_item_unlocked+0x154/0x344 fs/configfs/dir.c:1268 usbg_make_tpg+0x218/0x4a0 drivers/usb/gadget/function/f_tcm.c:1692 target_fabric_make_tpg+0x98/0x518 drivers/target/target_core_fabric_configfs.c:947 configfs_mkdir+0x374/0x7d4 fs/configfs/dir.c:1369 vfs_mkdir+0x2e4/0x46c fs/namei.c:5439 filename_mkdirat+0x228/0x3f4 fs/namei.c:5472 __do_sys_mkdirat fs/namei.c:5493 [inline] __se_sys_mkdirat fs/namei.c:5490 [inline] __arm64_sys_mkdirat+0x9c/0xc0 fs/namei.c:5490 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606 other info that might help us debug this: Chain exists of: &sb->s_type->i_mutex_key#30 --> &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#30); *** DEADLOCK *** locks held by syz.5.1016/10280: 4, last CPU#0: #0: ffff0000c3a64460 (sb_writers#21){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:527 #1: ffff0000daf3d900 (&sb->s_type->i_mutex_key#7/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1069 [inline] #1: ffff0000daf3d900 (&sb->s_type->i_mutex_key#7/1){+.+.}-{4:4}, at: __start_dirop+0xa0/0xf4 fs/namei.c:2947 #2: ffff80008a16c5e8 (&subsys->su_mutex){+.+.}-{4:4}, at: configfs_mkdir+0x334/0x7d4 fs/configfs/dir.c:1367 #3: ffff80008a46cd60 (tpg_instances_lock){+.+.}-{4:4}, at: usbg_make_tpg+0x14c/0x4a0 drivers/usb/gadget/function/f_tcm.c:1669 stack backtrace: CPU: 0 UID: 0 PID: 10280 Comm: syz.5.1016 Not tainted syzkaller #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/23/2026 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x328/0x330 kernel/locking/lockdep.c:2087 check_noncircular+0x158/0x174 kernel/locking/lockdep.c:2219 check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x1660/0x2b08 kernel/locking/lockdep.c:5288 lock_acquire+0x13c/0x320 kernel/locking/lockdep.c:5942 down_write+0xac/0x2a8 kernel/locking/rwsem.c:1631 inode_lock include/linux/fs.h:1024 [inline] configfs_depend_item_unlocked+0x154/0x344 fs/configfs/dir.c:1268 usbg_make_tpg+0x218/0x4a0 drivers/usb/gadget/function/f_tcm.c:1692 target_fabric_make_tpg+0x98/0x518 drivers/target/target_core_fabric_configfs.c:947 configfs_mkdir+0x374/0x7d4 fs/configfs/dir.c:1369 vfs_mkdir+0x2e4/0x46c fs/namei.c:5439 filename_mkdirat+0x228/0x3f4 fs/namei.c:5472 __do_sys_mkdirat fs/namei.c:5493 [inline] __se_sys_mkdirat fs/namei.c:5490 [inline] __arm64_sys_mkdirat+0x9c/0xc0 fs/namei.c:5490 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606