====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.17/5926 is trying to acquire lock: ffff888034d27878 (&of->mutex){+.+.}-{4:4}, at: kernfs_seq_start+0x5d/0x420 fs/kernfs/file.c:165 but task is already holding lock: ffff888033283db0 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xa5/0xcb0 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/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 seq_read_iter+0xa5/0xcb0 fs/seq_file.c:183 copy_splice_read+0x605/0xab0 fs/splice.c:346 do_splice_read fs/splice.c:963 [inline] splice_file_to_pipe+0x450/0x6c0 fs/splice.c:1273 do_sendfile+0x4e6/0x7e0 fs/read_write.c:1400 __do_sys_sendfile64 fs/read_write.c:1455 [inline] __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1441 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (&pipe->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 anon_pipe_write+0x290/0x1c30 fs/pipe.c:553 __kernel_write_iter+0x453/0x8f0 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+0x777/0xed0 fs/autofs/waitq.c:164 autofs_wait+0x11d8/0x18b0 fs/autofs/waitq.c:426 autofs_mount_wait+0x16b/0x390 fs/autofs/root.c:256 autofs_d_automount+0x64e/0x810 fs/autofs/root.c:410 follow_automount fs/namei.c:1565 [inline] __traverse_mounts+0x2fe/0x5d0 fs/namei.c:1618 traverse_mounts fs/namei.c:1647 [inline] handle_mounts fs/namei.c:1749 [inline] step_into_slowpath+0x4ba/0x820 fs/namei.c:2104 step_into fs/namei.c:2152 [inline] walk_component fs/namei.c:2288 [inline] lookup_last fs/namei.c:2789 [inline] path_lookupat+0x433/0x8c0 fs/namei.c:2813 filename_lookup+0x265/0x5d0 fs/namei.c:2842 kern_path+0x3d/0x150 fs/namei.c:3036 lookup_bdev+0xc8/0x290 block/bdev.c:1208 resume_store+0x16f/0x4f0 kernel/power/hibernate.c:1278 kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61e/0xbb0 fs/read_write.c:687 ksys_write+0x156/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 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/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x764/0xed0 fs/autofs/waitq.c:164 autofs_wait+0x11d8/0x18b0 fs/autofs/waitq.c:426 autofs_mount_wait+0x16b/0x390 fs/autofs/root.c:256 autofs_d_automount+0x64e/0x810 fs/autofs/root.c:410 follow_automount fs/namei.c:1565 [inline] __traverse_mounts+0x2fe/0x5d0 fs/namei.c:1618 traverse_mounts fs/namei.c:1647 [inline] handle_mounts fs/namei.c:1749 [inline] step_into_slowpath+0x4ba/0x820 fs/namei.c:2104 step_into fs/namei.c:2152 [inline] walk_component fs/namei.c:2288 [inline] lookup_last fs/namei.c:2789 [inline] path_lookupat+0x433/0x8c0 fs/namei.c:2813 filename_lookup+0x265/0x5d0 fs/namei.c:2842 kern_path+0x3d/0x150 fs/namei.c:3036 lookup_bdev+0xc8/0x290 block/bdev.c:1208 resume_store+0x16f/0x4f0 kernel/power/hibernate.c:1278 kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61e/0xbb0 fs/read_write.c:687 ksys_write+0x156/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 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:3167 [inline] check_prevs_add kernel/locking/lockdep.c:3286 [inline] validate_chain kernel/locking/lockdep.c:3910 [inline] __lock_acquire+0x1520/0x2ce0 kernel/locking/lockdep.c:5239 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5870 __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 kernfs_seq_start+0x5d/0x420 fs/kernfs/file.c:165 seq_read_iter+0x37f/0xcb0 fs/seq_file.c:226 copy_splice_read+0x605/0xab0 fs/splice.c:346 do_splice_read fs/splice.c:963 [inline] splice_file_to_pipe+0x450/0x6c0 fs/splice.c:1273 do_sendfile+0x4e6/0x7e0 fs/read_write.c:1400 __do_sys_sendfile64 fs/read_write.c:1455 [inline] __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1441 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 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.0.17/5926: #0: ffff8880388f9858 (&pipe->mutex){+.+.}-{4:4}, at: splice_file_to_pipe+0x3e/0x6c0 fs/splice.c:1270 #1: ffff888033283db0 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xa5/0xcb0 fs/seq_file.c:183 stack backtrace: CPU: 0 UID: 0 PID: 5926 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2045 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2177 check_prev_add kernel/locking/lockdep.c:3167 [inline] check_prevs_add kernel/locking/lockdep.c:3286 [inline] validate_chain kernel/locking/lockdep.c:3910 [inline] __lock_acquire+0x1520/0x2ce0 kernel/locking/lockdep.c:5239 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5870 __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 kernfs_seq_start+0x5d/0x420 fs/kernfs/file.c:165 seq_read_iter+0x37f/0xcb0 fs/seq_file.c:226 copy_splice_read+0x605/0xab0 fs/splice.c:346 do_splice_read fs/splice.c:963 [inline] splice_file_to_pipe+0x450/0x6c0 fs/splice.c:1273 do_sendfile+0x4e6/0x7e0 fs/read_write.c:1400 __do_sys_sendfile64 fs/read_write.c:1455 [inline] __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1441 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f434391ce59 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:00007f4342f5d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f4343b96090 RCX: 00007f434391ce59 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000 RBP: 00007f43439b2d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4343b96128 R14: 00007f4343b96090 R15: 00007ffdf38cb748