====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.3.5809/22652 is trying to acquire lock: ffff88803743e138 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_write fs/autofs/waitq.c:55 [inline] ffff88803743e138 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_notify_daemon+0x4f8/0xd90 fs/autofs/waitq.c:164 but task is already holding lock: ffff8880784be480 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&of->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:632 [inline] __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806 kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 traverse.part.0.constprop.0+0xaf/0x650 fs/seq_file.c:107 traverse fs/seq_file.c:99 [inline] seq_read_iter+0x93f/0x1270 fs/seq_file.c:196 kernfs_fop_read_iter+0x46c/0x610 fs/kernfs/file.c:297 do_iter_readv_writev+0x60d/0x920 fs/read_write.c:827 vfs_readv+0x4d3/0x8d0 fs/read_write.c:1020 do_readv+0x13e/0x340 fs/read_write.c:1082 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (&p->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:632 [inline] __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806 seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 kernfs_fop_read_iter+0x46c/0x610 fs/kernfs/file.c:297 copy_splice_read+0x4ba/0xb90 fs/splice.c:362 do_splice_read fs/splice.c:980 [inline] do_splice_read+0x285/0x370 fs/splice.c:954 splice_file_to_pipe+0x82/0x120 fs/splice.c:1290 do_sendfile+0x366/0xe20 fs/read_write.c:1378 __do_sys_sendfile64 fs/read_write.c:1433 [inline] __se_sys_sendfile64 fs/read_write.c:1419 [inline] __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1419 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&pipe->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:632 [inline] __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806 anon_pipe_write+0x163/0x1d40 fs/pipe.c:458 __kernel_write_iter+0x6b2/0x920 fs/read_write.c:621 __kernel_write+0xf6/0x140 fs/read_write.c:641 autofs_write fs/autofs/waitq.c:57 [inline] autofs_notify_daemon+0x50d/0xd90 fs/autofs/waitq.c:164 autofs_wait+0x10fd/0x1b50 fs/autofs/waitq.c:426 autofs_mount_wait+0x132/0x3b0 fs/autofs/root.c:256 autofs_d_automount+0x490/0x950 fs/autofs/root.c:410 follow_automount fs/namei.c:1560 [inline] __traverse_mounts+0x1b9/0x8a0 fs/namei.c:1613 traverse_mounts fs/namei.c:1642 [inline] handle_mounts fs/namei.c:1744 [inline] step_into_slowpath+0xb7e/0xf90 fs/namei.c:2100 step_into fs/namei.c:2148 [inline] open_last_lookups fs/namei.c:4646 [inline] path_openat+0xf95/0x31a0 fs/namei.c:4855 do_file_open+0x20e/0x430 fs/namei.c:4887 do_sys_openat2+0x10d/0x1e0 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1381 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&sbi->pipe_mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:632 [inline] __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x4f8/0xd90 fs/autofs/waitq.c:164 autofs_wait+0x10fd/0x1b50 fs/autofs/waitq.c:426 autofs_mount_wait+0x132/0x3b0 fs/autofs/root.c:256 autofs_d_automount+0x490/0x950 fs/autofs/root.c:410 follow_automount fs/namei.c:1560 [inline] __traverse_mounts+0x1b9/0x8a0 fs/namei.c:1613 traverse_mounts fs/namei.c:1642 [inline] handle_mounts fs/namei.c:1744 [inline] step_into_slowpath+0xb7e/0xf90 fs/namei.c:2100 step_into fs/namei.c:2148 [inline] walk_component fs/namei.c:2284 [inline] lookup_last fs/namei.c:2785 [inline] path_lookupat+0x58b/0xc40 fs/namei.c:2809 filename_lookup+0x202/0x590 fs/namei.c:2838 kern_path+0x37/0x50 fs/namei.c:3044 lookup_bdev+0xd8/0x280 block/bdev.c:1213 resume_store+0x1d6/0x460 kernel/power/hibernate.c:1306 kobj_attr_store+0x58/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352 aio_write+0x3ba/0x920 fs/aio.c:1687 __io_submit_one fs/aio.c:2059 [inline] io_submit_one+0x1142/0x1fb0 fs/aio.c:2106 __do_sys_io_submit fs/aio.c:2165 [inline] __se_sys_io_submit fs/aio.c:2135 [inline] __x64_sys_io_submit+0x1b1/0x3a0 fs/aio.c:2135 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &sbi->pipe_mutex --> &p->lock --> &of->mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&of->mutex); lock(&p->lock); lock(&of->mutex); lock(&sbi->pipe_mutex); *** DEADLOCK *** 2 locks held by syz.3.5809/22652: #0: ffff8880784be480 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #1: ffff88801ea85698 (kn->active#89){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #1: ffff88801ea85698 (kn->active#89){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 stack backtrace: CPU: 0 UID: 0 PID: 22652 Comm: syz.3.5809 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:632 [inline] __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x4f8/0xd90 fs/autofs/waitq.c:164 autofs_wait+0x10fd/0x1b50 fs/autofs/waitq.c:426 autofs_mount_wait+0x132/0x3b0 fs/autofs/root.c:256 autofs_d_automount+0x490/0x950 fs/autofs/root.c:410 follow_automount fs/namei.c:1560 [inline] __traverse_mounts+0x1b9/0x8a0 fs/namei.c:1613 traverse_mounts fs/namei.c:1642 [inline] handle_mounts fs/namei.c:1744 [inline] step_into_slowpath+0xb7e/0xf90 fs/namei.c:2100 step_into fs/namei.c:2148 [inline] walk_component fs/namei.c:2284 [inline] lookup_last fs/namei.c:2785 [inline] path_lookupat+0x58b/0xc40 fs/namei.c:2809 filename_lookup+0x202/0x590 fs/namei.c:2838 kern_path+0x37/0x50 fs/namei.c:3044 lookup_bdev+0xd8/0x280 block/bdev.c:1213 resume_store+0x1d6/0x460 kernel/power/hibernate.c:1306 kobj_attr_store+0x58/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352 aio_write+0x3ba/0x920 fs/aio.c:1687 __io_submit_one fs/aio.c:2059 [inline] io_submit_one+0x1142/0x1fb0 fs/aio.c:2106 __do_sys_io_submit fs/aio.c:2165 [inline] __se_sys_io_submit fs/aio.c:2135 [inline] __x64_sys_io_submit+0x1b1/0x3a0 fs/aio.c:2135 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f517319c819 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:00007f517410a028 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1 RAX: ffffffffffffffda RBX: 00007f5173415fa0 RCX: 00007f517319c819 RDX: 0000200000000a80 RSI: 0000000000000001 RDI: 00007f51740e9000 RBP: 00007f5173232c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5173416038 R14: 00007f5173415fa0 R15: 00007ffc454128b8