====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.1608/11327 is trying to acquire lock: ffff88802bed5938 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_write fs/autofs/waitq.c:68 [inline] ffff88802bed5938 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_notify_daemon+0x75d/0xf10 fs/autofs/waitq.c:177 but task is already holding lock: ffff888033c60080 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 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:646 [inline] __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821 kernfs_seq_start+0x5d/0x420 fs/kernfs/file.c:165 seq_read_iter+0x37e/0xca0 fs/seq_file.c:226 copy_splice_read+0x5ff/0xaa0 fs/splice.c:362 do_splice_read fs/splice.c:980 [inline] splice_file_to_pipe+0x4ab/0x720 fs/splice.c:1318 do_sendfile+0x4d4/0x7c0 fs/read_write.c:2087 __do_sys_sendfile64 fs/read_write.c:2142 [inline] __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:2128 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 (&p->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821 seq_read_iter+0xa4/0xca0 fs/seq_file.c:183 copy_splice_read+0x5ff/0xaa0 fs/splice.c:362 do_splice_read fs/splice.c:980 [inline] splice_file_to_pipe+0x4ab/0x720 fs/splice.c:1318 do_sendfile+0x4d4/0x7c0 fs/read_write.c:2087 __do_sys_sendfile64 fs/read_write.c:2142 [inline] __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:2128 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 (&pipe->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821 anon_pipe_prefill_and_lock fs/pipe.c:165 [inline] anon_pipe_write+0x28f/0x1a90 fs/pipe.c:534 __kernel_write_iter+0x44a/0x8f0 fs/read_write.c:621 __kernel_write+0x106/0x170 fs/read_write.c:641 autofs_write fs/autofs/waitq.c:70 [inline] autofs_notify_daemon+0x770/0xf10 fs/autofs/waitq.c:177 autofs_wait+0x11ad/0x18a0 fs/autofs/waitq.c:439 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:1571 [inline] __traverse_mounts+0x2fe/0x5d0 fs/namei.c:1624 traverse_mounts fs/namei.c:1653 [inline] handle_mounts fs/namei.c:1755 [inline] step_into_slowpath+0x4ba/0x820 fs/namei.c:2110 step_into fs/namei.c:2158 [inline] walk_component fs/namei.c:2294 [inline] lookup_last fs/namei.c:2795 [inline] path_lookupat+0x433/0x8c0 fs/namei.c:2819 filename_lookup+0x265/0x5d0 fs/namei.c:2848 user_statfs+0xb2/0x1c0 fs/statfs.c:104 __do_sys_statfs fs/statfs.c:194 [inline] __se_sys_statfs fs/statfs.c:191 [inline] __x64_sys_statfs+0x120/0x270 fs/statfs.c:191 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 (&sbi->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 autofs_write fs/autofs/waitq.c:68 [inline] autofs_notify_daemon+0x75d/0xf10 fs/autofs/waitq.c:177 autofs_wait+0x11ad/0x18a0 fs/autofs/waitq.c:439 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:1571 [inline] __traverse_mounts+0x2fe/0x5d0 fs/namei.c:1624 traverse_mounts fs/namei.c:1653 [inline] handle_mounts fs/namei.c:1755 [inline] step_into_slowpath+0x4ba/0x820 fs/namei.c:2110 step_into fs/namei.c:2158 [inline] walk_component fs/namei.c:2294 [inline] lookup_last fs/namei.c:2795 [inline] path_lookupat+0x433/0x8c0 fs/namei.c:2819 filename_lookup+0x265/0x5d0 fs/namei.c:2848 kern_path+0x3d/0x150 fs/namei.c:3042 lookup_bdev+0xc8/0x2b0 block/bdev.c:1268 resume_store+0x181/0x500 kernel/power/hibernate.c:1286 kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x612/0xba0 fs/read_write.c:687 ksys_write+0x150/0x270 fs/read_write.c:1036 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: &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 *** locks held by syz.2.1608/11327: 4, last CPU#0: #0: ffff88807efba630 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x118/0x160 fs/file.c:1409 #1: ffff888038154478 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2762 [inline] #1: ffff888038154478 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #2: ffff888033c60080 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #3: ffff88801f6b6698 (kn->active#89){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #3: ffff88801f6b6698 (kn->active#89){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 stack backtrace: CPU: 0 UID: 0 PID: 11327 Comm: syz.2.1608 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 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 autofs_write fs/autofs/waitq.c:68 [inline] autofs_notify_daemon+0x75d/0xf10 fs/autofs/waitq.c:177 autofs_wait+0x11ad/0x18a0 fs/autofs/waitq.c:439 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:1571 [inline] __traverse_mounts+0x2fe/0x5d0 fs/namei.c:1624 traverse_mounts fs/namei.c:1653 [inline] handle_mounts fs/namei.c:1755 [inline] step_into_slowpath+0x4ba/0x820 fs/namei.c:2110 step_into fs/namei.c:2158 [inline] walk_component fs/namei.c:2294 [inline] lookup_last fs/namei.c:2795 [inline] path_lookupat+0x433/0x8c0 fs/namei.c:2819 filename_lookup+0x265/0x5d0 fs/namei.c:2848 kern_path+0x3d/0x150 fs/namei.c:3042 lookup_bdev+0xc8/0x2b0 block/bdev.c:1268 resume_store+0x181/0x500 kernel/power/hibernate.c:1286 kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x612/0xba0 fs/read_write.c:687 ksys_write+0x150/0x270 fs/read_write.c:1036 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: 0033:0x7ff19a19f559 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:00007ff19b004028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007ff19a425fa0 RCX: 00007ff19a19f559 RDX: 0000000000000012 RSI: 00002000000000c0 RDI: 0000000000000008 RBP: 00007ff19a236b20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff19a426038 R14: 00007ff19a425fa0 R15: 00007ffd37eddf88 PM: Image not found (code -6)