====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.2.4003/22897 is trying to acquire lock: ffff888059056148 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_write fs/autofs/waitq.c:55 [inline] ffff888059056148 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_notify_daemon+0x6d4/0xde0 fs/autofs/waitq.c:164 but task is already holding lock: ffff888035360088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 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:614 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:776 kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172 seq_read_iter+0x3f7/0xe20 fs/seq_file.c:226 new_sync_read fs/read_write.c:491 [inline] vfs_read+0x55a/0xa30 fs/read_write.c:572 ksys_read+0x145/0x250 fs/read_write.c:715 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/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:614 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:776 seq_read_iter+0xb7/0xe20 fs/seq_file.c:183 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/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:614 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:776 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+0x6e7/0xde0 fs/autofs/waitq.c:164 autofs_wait+0x11dc/0x18c0 fs/autofs/waitq.c:426 autofs_mount_wait+0x16b/0x390 fs/autofs/root.c:255 autofs_d_automount+0x64f/0x820 fs/autofs/root.c:409 follow_automount fs/namei.c:1499 [inline] __traverse_mounts+0x301/0x5e0 fs/namei.c:1552 traverse_mounts fs/namei.c:1581 [inline] handle_mounts fs/namei.c:1686 [inline] step_into_slowpath+0x469/0x7d0 fs/namei.c:2043 step_into fs/namei.c:2091 [inline] walk_component fs/namei.c:2227 [inline] lookup_last fs/namei.c:2722 [inline] path_lookupat+0x433/0x8c0 fs/namei.c:2746 filename_lookup+0x212/0x570 fs/namei.c:2775 user_path_at+0x3a/0x60 fs/namei.c:3567 do_sys_truncate+0xa3/0x190 fs/open.c:139 __do_sys_truncate fs/open.c:153 [inline] __se_sys_truncate fs/open.c:151 [inline] __x64_sys_truncate+0x5b/0x70 fs/open.c:151 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/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+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:776 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x6d4/0xde0 fs/autofs/waitq.c:164 autofs_wait+0x11dc/0x18c0 fs/autofs/waitq.c:426 autofs_mount_wait+0x16b/0x390 fs/autofs/root.c:255 autofs_d_automount+0x64f/0x820 fs/autofs/root.c:409 follow_automount fs/namei.c:1499 [inline] __traverse_mounts+0x301/0x5e0 fs/namei.c:1552 traverse_mounts fs/namei.c:1581 [inline] handle_mounts fs/namei.c:1686 [inline] step_into_slowpath+0x469/0x7d0 fs/namei.c:2043 step_into fs/namei.c:2091 [inline] walk_component fs/namei.c:2227 [inline] lookup_last fs/namei.c:2722 [inline] path_lookupat+0x433/0x8c0 fs/namei.c:2746 filename_lookup+0x212/0x570 fs/namei.c:2775 kern_path+0x35/0x50 fs/namei.c:2987 lookup_bdev+0xc0/0x280 block/bdev.c:1222 resume_store+0x169/0x480 kernel/power/hibernate.c:1306 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/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 *** 4 locks held by syz.2.4003/22897: #0: ffff888030e86478 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1255 #1: ffff888033c8e420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2680 [inline] #1: ffff888033c8e420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x211/0xb30 fs/read_write.c:682 #2: ffff888035360088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #3: ffff88801eadc2d8 (kn->active#76){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #3: ffff88801eadc2d8 (kn->active#76){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 stack backtrace: CPU: 0 UID: 0 PID: 22897 Comm: syz.2.4003 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 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+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:776 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x6d4/0xde0 fs/autofs/waitq.c:164 autofs_wait+0x11dc/0x18c0 fs/autofs/waitq.c:426 autofs_mount_wait+0x16b/0x390 fs/autofs/root.c:255 autofs_d_automount+0x64f/0x820 fs/autofs/root.c:409 follow_automount fs/namei.c:1499 [inline] __traverse_mounts+0x301/0x5e0 fs/namei.c:1552 traverse_mounts fs/namei.c:1581 [inline] handle_mounts fs/namei.c:1686 [inline] step_into_slowpath+0x469/0x7d0 fs/namei.c:2043 step_into fs/namei.c:2091 [inline] walk_component fs/namei.c:2227 [inline] lookup_last fs/namei.c:2722 [inline] path_lookupat+0x433/0x8c0 fs/namei.c:2746 filename_lookup+0x212/0x570 fs/namei.c:2775 kern_path+0x35/0x50 fs/namei.c:2987 lookup_bdev+0xc0/0x280 block/bdev.c:1222 resume_store+0x169/0x480 kernel/power/hibernate.c:1306 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/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f797b58f749 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:00007f797c3b3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f797b7e5fa0 RCX: 00007f797b58f749 RDX: 0000000000000012 RSI: 0000200000000040 RDI: 0000000000000003 RBP: 00007f797b613f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f797b7e6038 R14: 00007f797b7e5fa0 R15: 00007ffc36444d08 PM: Image not found (code -22)