====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.3.2379/11273 is trying to acquire lock: ffff800017fb6090 (gadget_subsys.su_mutex){+.+.}-{3:3}, at: uvcg_streaming_header_allow_link+0x78/0x488 drivers/usb/gadget/function/uvc_configfs.c:884 but task is already holding lock: ffff0001000aaee0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock include/linux/fs.h:764 [inline] ffff0001000aaee0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: configfs_symlink+0x310/0xee0 fs/configfs/symlink.c:192 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&sb->s_type->i_mutex_key#20){++++}-{3:3}: 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 -> #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_inst+0x6c/0x190 drivers/usb/gadget/function/f_tcm.c:2366 try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline] usb_get_function_instance+0xe8/0x2dc drivers/usb/gadget/functions.c:44 function_make+0x108/0x2f8 drivers/usb/gadget/configfs.c:615 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 -> #1 (func_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 try_get_usb_function_instance drivers/usb/gadget/functions.c:18 [inline] usb_get_function_instance+0x3c/0x2dc drivers/usb/gadget/functions.c:44 function_make+0x108/0x2f8 drivers/usb/gadget/configfs.c:615 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 -> #0 (gadget_subsys.su_mutex){+.+.}-{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 __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 uvcg_streaming_header_allow_link+0x78/0x488 drivers/usb/gadget/function/uvc_configfs.c:884 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 other info that might help us debug this: Chain exists of: gadget_subsys.su_mutex --> tpg_instances_lock --> &sb->s_type->i_mutex_key#20 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#20); lock(tpg_instances_lock); lock(&sb->s_type->i_mutex_key#20); lock(gadget_subsys.su_mutex); *** DEADLOCK *** 2 locks held by syz.3.2379/11273: #0: ffff0000c7b68460 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:402 #1: ffff0001000aaee0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock include/linux/fs.h:764 [inline] #1: ffff0001000aaee0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: configfs_symlink+0x310/0xee0 fs/configfs/symlink.c:192 stack backtrace: CPU: 0 PID: 11273 Comm: syz.3.2379 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/23/2026 dump_backtrace(regs = 0000000000000000 tsk = 0000000000000000) 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 __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 uvcg_streaming_header_allow_link+0x78/0x488 drivers/usb/gadget/function/uvc_configfs.c:884 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 configfs: configfs_get_target_path: depth = 7, size = 76 configfs: configfs_get_target_path: path = '../../../../../../../usb_gadget/g1/functions/uvc.0/streaming/uncompressed/u' kcov: kcov_task_exit: t = ffff0000d9608000, kcov->t = ffff0000d9608000