====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.3.318/5594 is trying to acquire lock: ffff0000c683d080 (&sb->s_type->i_mutex_key#24){++++}-{3:3}, at: inode_lock include/linux/fs.h:764 [inline] ffff0000c683d080 (&sb->s_type->i_mutex_key#24){++++}-{3:3}, at: configfs_depend_item_unlocked+0x128/0x434 fs/configfs/dir.c:1251 but task is already holding lock: ffff8000180105a8 (tpg_instances_lock){+.+.}-{3:3}, at: usbg_make_tpg+0x100/0x4ac drivers/usb/gadget/function/f_tcm.c:1348 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (tpg_instances_lock){+.+.}-{3:3}: __mutex_lock_common+0x1a0/0x1f3c kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 tcm_alloc+0x30/0x2d4 drivers/usb/gadget/function/f_tcm.c:2413 usb_get_function+0x64/0xb0 drivers/usb/gadget/functions.c:61 config_usb_cfg_link+0x13c/0x22c drivers/usb/gadget/configfs.c:459 configfs_symlink+0x468/0xee0 fs/configfs/symlink.c:202 vfs_symlink+0x238/0x3b0 fs/namei.c:4522 do_symlinkat+0x178/0x35c fs/namei.c:4551 __do_sys_symlinkat fs/namei.c:4568 [inline] __se_sys_symlinkat fs/namei.c:4565 [inline] __arm64_sys_symlinkat+0xa4/0xbc fs/namei.c:4565 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 -> #1 (&gi->lock){+.+.}-{3:3}: __mutex_lock_common+0x1a0/0x1f3c kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 config_usb_cfg_link+0x5c/0x22c drivers/usb/gadget/configfs.c:429 configfs_symlink+0x468/0xee0 fs/configfs/symlink.c:202 vfs_symlink+0x238/0x3b0 fs/namei.c:4522 do_symlinkat+0x178/0x35c fs/namei.c:4551 __do_sys_symlinkat fs/namei.c:4568 [inline] __se_sys_symlinkat fs/namei.c:4565 [inline] __arm64_sys_symlinkat+0xa4/0xbc fs/namei.c:4565 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 -> #0 (&sb->s_type->i_mutex_key#24){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3162 [inline] check_prevs_add kernel/locking/lockdep.c:3281 [inline] validate_chain kernel/locking/lockdep.c:3897 [inline] __lock_acquire+0x3504/0x7280 kernel/locking/lockdep.c:5171 lock_acquire+0x210/0x63c kernel/locking/lockdep.c:5790 down_write+0x5c/0x88 kernel/locking/rwsem.c:1573 inode_lock include/linux/fs.h:764 [inline] configfs_depend_item_unlocked+0x128/0x434 fs/configfs/dir.c:1251 usbg_make_tpg+0x1c4/0x4ac drivers/usb/gadget/function/f_tcm.c:1371 target_fabric_make_tpg+0x98/0x518 drivers/target/target_core_fabric_configfs.c:913 configfs_mkdir+0x3e0/0x884 fs/configfs/dir.c:1356 vfs_mkdir+0x314/0x4d8 fs/namei.c:4157 do_mkdirat+0x1b8/0x3ec fs/namei.c:4182 __do_sys_mkdirat fs/namei.c:4197 [inline] __se_sys_mkdirat fs/namei.c:4195 [inline] __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4195 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 other info that might help us debug this: Chain exists of: &sb->s_type->i_mutex_key#24 --> &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#24); *** DEADLOCK *** 4 locks held by syz.3.318/5594: #0: ffff0000c719c460 (sb_writers#16){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:402 #1: ffff0000f5dddfb0 (&sb->s_type->i_mutex_key#7/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:799 [inline] #1: ffff0000f5dddfb0 (&sb->s_type->i_mutex_key#7/1){+.+.}-{3:3}, at: filename_create+0x1b0/0x3a8 fs/namei.c:3927 #2: ffff800017bad030 (&subsys->su_mutex){+.+.}-{3:3}, at: configfs_mkdir+0x3a0/0x884 fs/configfs/dir.c:1354 #3: ffff8000180105a8 (tpg_instances_lock){+.+.}-{3:3}, at: usbg_make_tpg+0x100/0x4ac drivers/usb/gadget/function/f_tcm.c:1348 stack backtrace: CPU: 0 PID: 5594 Comm: syz.3.318 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2026 Call trace: dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2088 check_noncircular+0x290/0x370 kernel/locking/lockdep.c:2215 check_prev_add kernel/locking/lockdep.c:3162 [inline] check_prevs_add kernel/locking/lockdep.c:3281 [inline] validate_chain kernel/locking/lockdep.c:3897 [inline] __lock_acquire+0x3504/0x7280 kernel/locking/lockdep.c:5171 lock_acquire+0x210/0x63c kernel/locking/lockdep.c:5790 down_write+0x5c/0x88 kernel/locking/rwsem.c:1573 inode_lock include/linux/fs.h:764 [inline] configfs_depend_item_unlocked+0x128/0x434 fs/configfs/dir.c:1251 usbg_make_tpg+0x1c4/0x4ac drivers/usb/gadget/function/f_tcm.c:1371 target_fabric_make_tpg+0x98/0x518 drivers/target/target_core_fabric_configfs.c:913 configfs_mkdir+0x3e0/0x884 fs/configfs/dir.c:1356 vfs_mkdir+0x314/0x4d8 fs/namei.c:4157 do_mkdirat+0x1b8/0x3ec fs/namei.c:4182 __do_sys_mkdirat fs/namei.c:4197 [inline] __se_sys_mkdirat fs/namei.c:4195 [inline] __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4195 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585