====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.16/6461 is trying to acquire lock: ffff88803287ec88 (&of->mutex){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172 but task is already holding lock: ffff888031026418 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe20 fs/seq_file.c:182 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 seq_read_iter+0xb7/0xe20 fs/seq_file.c:182 copy_splice_read+0x5d4/0xa50 fs/splice.c:363 do_splice_read fs/splice.c:982 [inline] splice_file_to_pipe+0x273/0x440 fs/splice.c:1292 do_sendfile+0x475/0x7e0 fs/read_write.c:1376 __do_sys_sendfile64 fs/read_write.c:1431 [inline] __se_sys_sendfile64+0x13e/0x190 fs/read_write.c:1417 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (&pipe->mutex){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 anon_pipe_write+0x15d/0x1460 fs/pipe.c:458 __kernel_write_iter+0x481/0x910 fs/read_write.c:619 __kernel_write+0xef/0x150 fs/read_write.c:639 autofs_write fs/autofs/waitq.c:57 [inline] autofs_notify_daemon+0x748/0xe50 fs/autofs/waitq.c:164 autofs_wait+0x11dc/0x1870 fs/autofs/waitq.c:426 autofs_mount_wait+0x16b/0x330 fs/autofs/root.c:255 autofs_d_automount+0x393/0x720 fs/autofs/root.c:401 follow_automount fs/namei.c:1459 [inline] __traverse_mounts+0x301/0x5e0 fs/namei.c:1512 traverse_mounts fs/namei.c:1541 [inline] handle_mounts fs/namei.c:1644 [inline] step_into+0x4f2/0xe80 fs/namei.c:1989 lookup_last fs/namei.c:2652 [inline] path_lookupat+0x163/0x430 fs/namei.c:2676 filename_lookup+0x212/0x570 fs/namei.c:2705 kern_path+0x35/0x50 fs/namei.c:2863 lookup_bdev+0xc0/0x280 block/bdev.c:1205 resume_store+0x169/0x460 kernel/power/hibernate.c:1309 kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&sbi->pipe_mutex){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x735/0xe50 fs/autofs/waitq.c:164 autofs_wait+0x11dc/0x1870 fs/autofs/waitq.c:426 autofs_mount_wait+0x16b/0x330 fs/autofs/root.c:255 autofs_d_automount+0x393/0x720 fs/autofs/root.c:401 follow_automount fs/namei.c:1459 [inline] __traverse_mounts+0x301/0x5e0 fs/namei.c:1512 traverse_mounts fs/namei.c:1541 [inline] handle_mounts fs/namei.c:1644 [inline] step_into+0x4f2/0xe80 fs/namei.c:1989 lookup_last fs/namei.c:2652 [inline] path_lookupat+0x163/0x430 fs/namei.c:2676 filename_lookup+0x212/0x570 fs/namei.c:2705 kern_path+0x35/0x50 fs/namei.c:2863 lookup_bdev+0xc0/0x280 block/bdev.c:1205 resume_store+0x169/0x460 kernel/power/hibernate.c:1309 kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&of->mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172 seq_read_iter+0x3f7/0xe20 fs/seq_file.c:225 copy_splice_read+0x5d4/0xa50 fs/splice.c:363 do_splice_read fs/splice.c:982 [inline] splice_file_to_pipe+0x273/0x440 fs/splice.c:1292 do_sendfile+0x475/0x7e0 fs/read_write.c:1376 __do_sys_sendfile64 fs/read_write.c:1431 [inline] __se_sys_sendfile64+0x13e/0x190 fs/read_write.c:1417 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 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: &of->mutex --> &pipe->mutex --> &p->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(&pipe->mutex); lock(&p->lock); lock(&of->mutex); *** DEADLOCK *** 2 locks held by syz.0.16/6461: #0: ffff888032866468 (&pipe->mutex){+.+.}-{4:4}, at: splice_file_to_pipe+0x2e/0x440 fs/splice.c:1289 #1: ffff888031026418 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe20 fs/seq_file.c:182 stack backtrace: CPU: 0 UID: 0 PID: 6461 Comm: syz.0.16 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 check_noncircular+0x134/0x160 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+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172 seq_read_iter+0x3f7/0xe20 fs/seq_file.c:225 copy_splice_read+0x5d4/0xa50 fs/splice.c:363 do_splice_read fs/splice.c:982 [inline] splice_file_to_pipe+0x273/0x440 fs/splice.c:1292 do_sendfile+0x475/0x7e0 fs/read_write.c:1376 __do_sys_sendfile64 fs/read_write.c:1431 [inline] __se_sys_sendfile64+0x13e/0x190 fs/read_write.c:1417 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f437978e9a9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f43789fe038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f43799b6080 RCX: 00007f437978e9a9 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000 RBP: 00007f4379810d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f43799b6080 R15: 00007ffcfd9a9408