====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.17/6442 is trying to acquire lock: ffff8880341fc888 (&of->mutex){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172 but task is already holding lock: ffff88803475bc30 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10 fs/seq_file.c:183 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 seq_read_iter+0xb7/0xe10 fs/seq_file.c:183 copy_splice_read+0x5ff/0xaa0 fs/splice.c:363 do_splice_read fs/splice.c:982 [inline] splice_file_to_pipe+0x446/0x6b0 fs/splice.c:1292 do_sendfile+0x4db/0x7d0 fs/read_write.c:1378 __do_sys_sendfile64 fs/read_write.c:1433 [inline] __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1419 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (&pipe->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 anon_pipe_write+0x15b/0x1480 fs/pipe.c:458 __kernel_write_iter+0x41e/0x880 fs/read_write.c:621 __kernel_write+0x106/0x170 fs/read_write.c:641 autofs_write fs/autofs/waitq.c:57 [inline] autofs_notify_daemon+0x73d/0xe80 fs/autofs/waitq.c:164 autofs_wait+0x1241/0x1910 fs/autofs/waitq.c:426 autofs_mount_wait+0x16b/0x390 fs/autofs/root.c:255 autofs_d_automount+0x64e/0x810 fs/autofs/root.c:409 follow_automount fs/namei.c:1560 [inline] __traverse_mounts+0x301/0x5d0 fs/namei.c:1613 traverse_mounts fs/namei.c:1642 [inline] handle_mounts fs/namei.c:1744 [inline] step_into_slowpath+0x475/0x7e0 fs/namei.c:2101 step_into fs/namei.c:2149 [inline] walk_component fs/namei.c:2285 [inline] lookup_last fs/namei.c:2780 [inline] path_lookupat+0x433/0x8c0 fs/namei.c:2804 filename_lookup+0x256/0x5d0 fs/namei.c:2833 kern_path+0x3d/0x150 fs/namei.c:3040 lookup_bdev+0xc8/0x290 block/bdev.c:1222 resume_store+0x16f/0x4f0 kernel/power/hibernate.c:1306 kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61d/0xb90 fs/read_write.c:688 ksys_write+0x150/0x270 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&sbi->pipe_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x72a/0xe80 fs/autofs/waitq.c:164 autofs_wait+0x1241/0x1910 fs/autofs/waitq.c:426 autofs_mount_wait+0x16b/0x390 fs/autofs/root.c:255 autofs_d_automount+0x64e/0x810 fs/autofs/root.c:409 follow_automount fs/namei.c:1560 [inline] __traverse_mounts+0x301/0x5d0 fs/namei.c:1613 traverse_mounts fs/namei.c:1642 [inline] handle_mounts fs/namei.c:1744 [inline] step_into_slowpath+0x475/0x7e0 fs/namei.c:2101 step_into fs/namei.c:2149 [inline] walk_component fs/namei.c:2285 [inline] lookup_last fs/namei.c:2780 [inline] path_lookupat+0x433/0x8c0 fs/namei.c:2804 filename_lookup+0x256/0x5d0 fs/namei.c:2833 kern_path+0x3d/0x150 fs/namei.c:3040 lookup_bdev+0xc8/0x290 block/bdev.c:1222 resume_store+0x16f/0x4f0 kernel/power/hibernate.c:1306 kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61d/0xb90 fs/read_write.c:688 ksys_write+0x150/0x270 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 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 kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172 seq_read_iter+0x3f7/0xe10 fs/seq_file.c:226 copy_splice_read+0x5ff/0xaa0 fs/splice.c:363 do_splice_read fs/splice.c:982 [inline] splice_file_to_pipe+0x446/0x6b0 fs/splice.c:1292 do_sendfile+0x4db/0x7d0 fs/read_write.c:1378 __do_sys_sendfile64 fs/read_write.c:1433 [inline] __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1419 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 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: &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.0.17/6442: #0: ffff88801ead6468 (&pipe->mutex){+.+.}-{4:4}, at: splice_file_to_pipe+0x40/0x6b0 fs/splice.c:1289 #1: ffff88803475bc30 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10 fs/seq_file.c:183 stack backtrace: CPU: 1 UID: 0 PID: 6442 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 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+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172 seq_read_iter+0x3f7/0xe10 fs/seq_file.c:226 copy_splice_read+0x5ff/0xaa0 fs/splice.c:363 do_splice_read fs/splice.c:982 [inline] splice_file_to_pipe+0x446/0x6b0 fs/splice.c:1292 do_sendfile+0x4db/0x7d0 fs/read_write.c:1378 __do_sys_sendfile64 fs/read_write.c:1433 [inline] __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1419 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe79479aef9 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:00007fe795645028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fe794a06090 RCX: 00007fe79479aef9 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000 RBP: 00007fe79482fee0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe794a06128 R14: 00007fe794a06090 R15: 00007ffd80fb57b8