====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.2.3228/18408 is trying to acquire lock: ffff88806d13fc60 (&pipe->mutex){+.+.}-{4:4}, at: iter_file_splice_write+0x20a/0x1240 fs/splice.c:682 but task is already holding lock: ffff88801c2a8460 (sb_writers#5){.+.+}-{0:0}, at: do_splice+0xf11/0x19f0 fs/splice.c:1376 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (sb_writers#5){.+.+}-{0:0}: percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs/super.h:19 [inline] sb_start_write+0x48/0x1c0 include/linux/fs/super.h:125 mnt_want_write+0x41/0x90 fs/namespace.c:505 ovl_fix_origin fs/overlayfs/namei.c:940 [inline] ovl_lookup_layers fs/overlayfs/namei.c:1180 [inline] ovl_lookup+0xb93/0x1c80 fs/overlayfs/namei.c:1403 __lookup_slow+0x1fb/0x2f0 fs/namei.c:1919 lookup_slow+0x59/0x80 fs/namei.c:1936 walk_component fs/namei.c:2282 [inline] link_path_walk+0xd22/0x1910 fs/namei.c:2656 path_parentat fs/namei.c:2860 [inline] __filename_parentat+0x287/0x6f0 fs/namei.c:2884 filename_parentat fs/namei.c:2902 [inline] filename_unlinkat+0x104/0x610 fs/namei.c:5701 __do_sys_unlinkat fs/namei.c:5761 [inline] __se_sys_unlinkat+0x83/0x1a0 fs/namei.c:5753 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (DCACHE_PAR_LOOKUP){+.+.}-{0:0}: d_wait_lookup fs/dcache.c:2838 [inline] __d_alloc_parallel+0xc32/0x1700 fs/dcache.c:2942 __lookup_slow+0x82/0x2f0 fs/namei.c:1904 lookup_slow+0x59/0x80 fs/namei.c:1936 walk_component fs/namei.c:2282 [inline] link_path_walk+0xd22/0x1910 fs/namei.c:2656 path_openat+0x1c4/0x1da0 fs/namei.c:5007 do_file_open+0x23e/0x4a0 fs/namei.c:5040 do_sys_openat2+0x115/0x200 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_sys_openat fs/open.c:1464 [inline] __se_sys_openat fs/open.c:1459 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1459 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (&type->i_mutex_dir_key#3){++++}-{4:4}: down_read+0x45/0x320 kernel/locking/rwsem.c:1574 inode_lock_shared include/linux/fs.h:1039 [inline] lookup_open+0x221/0x1970 fs/namei.c:4460 open_last_lookups fs/namei.c:4769 [inline] path_openat+0x673/0x1da0 fs/namei.c:5008 do_file_open+0x23e/0x4a0 fs/namei.c:5040 file_open_name fs/open.c:1400 [inline] filp_open+0x16d/0x1d0 fs/open.c:1417 kernel_read_file_from_path_initns+0xde/0x1e0 fs/kernel_read_file.c:159 fw_get_filesystem_firmware drivers/base/firmware_loader/main.c:549 [inline] _request_firmware+0xa2b/0x1750 drivers/base/firmware_loader/main.c:873 request_firmware+0x36/0x50 drivers/base/firmware_loader/main.c:948 reg_reload_regdb+0x95/0x490 net/wireless/reg.c:1067 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2572 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline] netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1361 netlink_sendmsg+0x7c3/0xae0 net/netlink/af_netlink.c:1916 sock_sendmsg_nosec+0x14e/0x190 net/socket.c:800 __sock_sendmsg net/socket.c:818 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2715 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2769 __sys_sendmsg net/socket.c:2801 [inline] __do_sys_sendmsg net/socket.c:2806 [inline] __se_sys_sendmsg net/socket.c:2804 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2804 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (cb_lock){++++}-{4:4}: down_read+0x45/0x320 kernel/locking/rwsem.c:1574 genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline] netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1361 netlink_sendmsg+0x7c3/0xae0 net/netlink/af_netlink.c:1916 sock_sendmsg_nosec+0x14e/0x190 net/socket.c:800 __sock_sendmsg net/socket.c:818 [inline] sock_sendmsg+0x1ca/0x2d0 net/socket.c:841 splice_to_socket+0xc4d/0x1460 fs/splice.c:884 do_splice_from fs/splice.c:936 [inline] do_splice+0xf9e/0x19f0 fs/splice.c:1377 __do_splice fs/splice.c:1459 [inline] __do_sys_splice fs/splice.c:1662 [inline] __se_sys_splice+0x353/0x490 fs/splice.c:1644 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&pipe->mutex){+.+.}-{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+0x164c/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821 iter_file_splice_write+0x20a/0x1240 fs/splice.c:682 do_splice_from fs/splice.c:936 [inline] do_splice+0xf9e/0x19f0 fs/splice.c:1377 __do_splice fs/splice.c:1459 [inline] __do_sys_splice fs/splice.c:1662 [inline] __se_sys_splice+0x353/0x490 fs/splice.c:1644 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &pipe->mutex --> DCACHE_PAR_LOOKUP --> sb_writers#5 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(sb_writers#5); lock(DCACHE_PAR_LOOKUP); lock(sb_writers#5); lock(&pipe->mutex); *** DEADLOCK *** locks held by syz.2.3228/18408: 1, last CPU#0: #0: ffff88801c2a8460 (sb_writers#5){.+.+}-{0:0}, at: do_splice+0xf11/0x19f0 fs/splice.c:1376 stack backtrace: CPU: 0 UID: 0 PID: 18408 Comm: syz.2.3228 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2087 check_noncircular+0x12f/0x150 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+0x164c/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821 iter_file_splice_write+0x20a/0x1240 fs/splice.c:682 do_splice_from fs/splice.c:936 [inline] do_splice+0xf9e/0x19f0 fs/splice.c:1377 __do_splice fs/splice.c:1459 [inline] __do_sys_splice fs/splice.c:1662 [inline] __se_sys_splice+0x353/0x490 fs/splice.c:1644 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f353479e159 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:00007f35356eb028 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 00007f3534a25fa0 RCX: 00007f353479e159 RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 00007f353483506b R08: 0000000000000004 R09: 0000000000000000 R10: 0000200000000140 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3534a26038 R14: 00007f3534a25fa0 R15: 00007ffda49a4e08 bus: 'gadget': add driver configfs-gadget.g1 kobject: 'configfs-gadget.g1' (ffff888077789a00): kobject_add_internal: parent: 'drivers', set: 'drivers' kobject: 'configfs-gadget.g1' (ffff888077789a00): kobject_uevent_env kobject: 'configfs-gadget.g1' (ffff888077789a00): fill_kobj_path: path = '/bus/gadget/drivers/configfs-gadget.g1' UDC core: g1: couldn't find an available UDC or it's busy bus: 'gadget': remove driver configfs-gadget.g1 kernfs bind: removing kernfs unbind: removing kernfs uevent: removing kernfs module: removing kernfs gadget:configfs-gadget.g1: removing kobject: 'configfs-gadget.g1' (ffff888077789a00): kobject_cleanup, parent ffff8880236f0c50 kobject: 'configfs-gadget.g1' (ffff888077789a00): auto cleanup kobject_del kobject: 'configfs-gadget.g1' (ffff888077789a00): auto cleanup 'remove' event kobject: 'configfs-gadget.g1' (ffff888077789a00): kobject_uevent_env kobject: 'configfs-gadget.g1' (ffff888077789a00): fill_kobj_path: path = '/bus/gadget/drivers/configfs-gadget.g1' kernfs configfs-gadget.g1: removing kobject: 'configfs-gadget.g1' (ffff888077789a00): calling ktype release driver: 'configfs-gadget.g1': driver_release kobject: 'configfs-gadget.g1': free name kcov: kcov_task_exit: t = ffff888034fa5dc0, kcov->t = ffff888034fa5dc0