Hello, syzbot found the following issue on: HEAD commit: d7e78951a8b8 Merge tag 'net-6.11-rc0' of git://git.kernel... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1642f7a5980000 kernel config: https://syzkaller.appspot.com/x/.config?x=2602dfd9213d734c dashboard link: https://syzkaller.appspot.com/bug?extid=0d4e0978aa13f9e1db55 compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/cdd2c14644df/disk-d7e78951.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/7f9c9ab39b87/vmlinux-d7e78951.xz kernel image: https://storage.googleapis.com/syzbot-assets/1fc3658770e2/bzImage-d7e78951.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+0d4e0978aa13f9e1db55@xxxxxxxxxxxxxxxxxxxxxxxxx ====================================================== WARNING: possible circular locking dependency detected 6.10.0-syzkaller-09703-gd7e78951a8b8 #0 Not tainted ------------------------------------------------------ syz.3.4748/19551 is trying to acquire lock: ffff888059b0d940 (&sbi->pipe_mutex){+.+.}-{3:3}, at: autofs_write fs/autofs/waitq.c:55 [inline] ffff888059b0d940 (&sbi->pipe_mutex){+.+.}-{3:3}, at: autofs_notify_daemon+0x71f/0xf80 fs/autofs/waitq.c:164 but task is already holding lock: ffff8880758e7888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1eb/0x500 fs/kernfs/file.c:325 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&of->mutex){+.+.}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 kernfs_fop_write_iter+0x1eb/0x500 fs/kernfs/file.c:325 iter_file_splice_write+0xbd7/0x14e0 fs/splice.c:743 do_splice_from fs/splice.c:941 [inline] do_splice+0xd77/0x1900 fs/splice.c:1354 __do_splice fs/splice.c:1436 [inline] __do_sys_splice fs/splice.c:1652 [inline] __se_sys_splice+0x331/0x4a0 fs/splice.c:1634 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&pipe->mutex){+.+.}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 pipe_write+0x1c9/0x1a40 fs/pipe.c:455 __kernel_write_iter+0x47e/0x900 fs/read_write.c:523 __kernel_write+0x120/0x180 fs/read_write.c:543 autofs_write fs/autofs/waitq.c:57 [inline] autofs_notify_daemon+0x732/0xf80 fs/autofs/waitq.c:164 autofs_wait+0x10b8/0x1b30 fs/autofs/waitq.c:426 autofs_do_expire_multi+0x659/0x950 fs/autofs/expire.c:590 autofs_root_ioctl+0x4c/0x60 fs/autofs/root.c:910 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&sbi->pipe_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3133 [inline] check_prevs_add kernel/locking/lockdep.c:3252 [inline] validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3868 __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x71f/0xf80 fs/autofs/waitq.c:164 autofs_wait+0x10b8/0x1b30 fs/autofs/waitq.c:426 autofs_mount_wait+0x170/0x330 fs/autofs/root.c:255 autofs_d_automount+0x555/0x710 fs/autofs/root.c:401 follow_automount fs/namei.c:1394 [inline] __traverse_mounts+0x2ba/0x580 fs/namei.c:1439 traverse_mounts fs/namei.c:1468 [inline] handle_mounts fs/namei.c:1571 [inline] step_into+0x5e5/0x1080 fs/namei.c:1877 lookup_last fs/namei.c:2542 [inline] path_lookupat+0x16f/0x450 fs/namei.c:2566 filename_lookup+0x256/0x610 fs/namei.c:2595 kern_path+0x35/0x50 fs/namei.c:2703 lookup_bdev+0xc5/0x290 block/bdev.c:1157 resume_store+0x1a0/0x710 kernel/power/hibernate.c:1235 kernfs_fop_write_iter+0x3a1/0x500 fs/kernfs/file.c:334 iter_file_splice_write+0xbd7/0x14e0 fs/splice.c:743 do_splice_from fs/splice.c:941 [inline] direct_splice_actor+0x11e/0x220 fs/splice.c:1164 splice_direct_to_actor+0x58e/0xc90 fs/splice.c:1108 do_splice_direct_actor fs/splice.c:1207 [inline] do_splice_direct+0x28c/0x3e0 fs/splice.c:1233 do_sendfile+0x56d/0xe20 fs/read_write.c:1295 __do_sys_sendfile64 fs/read_write.c:1362 [inline] __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1348 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &sbi->pipe_mutex --> &pipe->mutex --> &of->mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&of->mutex); lock(&pipe->mutex); lock(&of->mutex); lock(&sbi->pipe_mutex); *** DEADLOCK *** 3 locks held by syz.3.4748/19551: #0: ffff88801e524420 (sb_writers#8){.+.+}-{0:0}, at: direct_splice_actor+0x49/0x220 fs/splice.c:1163 #1: ffff8880758e7888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1eb/0x500 fs/kernfs/file.c:325 #2: ffff888017adb4b8 (kn->active#65){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x20f/0x500 fs/kernfs/file.c:326 stack backtrace: CPU: 1 PID: 19551 Comm: syz.3.4748 Not tainted 6.10.0-syzkaller-09703-gd7e78951a8b8 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2186 check_prev_add kernel/locking/lockdep.c:3133 [inline] check_prevs_add kernel/locking/lockdep.c:3252 [inline] validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3868 __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x71f/0xf80 fs/autofs/waitq.c:164 autofs_wait+0x10b8/0x1b30 fs/autofs/waitq.c:426 autofs_mount_wait+0x170/0x330 fs/autofs/root.c:255 autofs_d_automount+0x555/0x710 fs/autofs/root.c:401 follow_automount fs/namei.c:1394 [inline] __traverse_mounts+0x2ba/0x580 fs/namei.c:1439 traverse_mounts fs/namei.c:1468 [inline] handle_mounts fs/namei.c:1571 [inline] step_into+0x5e5/0x1080 fs/namei.c:1877 lookup_last fs/namei.c:2542 [inline] path_lookupat+0x16f/0x450 fs/namei.c:2566 filename_lookup+0x256/0x610 fs/namei.c:2595 kern_path+0x35/0x50 fs/namei.c:2703 lookup_bdev+0xc5/0x290 block/bdev.c:1157 resume_store+0x1a0/0x710 kernel/power/hibernate.c:1235 kernfs_fop_write_iter+0x3a1/0x500 fs/kernfs/file.c:334 iter_file_splice_write+0xbd7/0x14e0 fs/splice.c:743 do_splice_from fs/splice.c:941 [inline] direct_splice_actor+0x11e/0x220 fs/splice.c:1164 splice_direct_to_actor+0x58e/0xc90 fs/splice.c:1108 do_splice_direct_actor fs/splice.c:1207 [inline] do_splice_direct+0x28c/0x3e0 fs/splice.c:1233 do_sendfile+0x56d/0xe20 fs/read_write.c:1295 __do_sys_sendfile64 fs/read_write.c:1362 [inline] __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1348 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f75ec575b59 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:00007f75ebfde048 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f75ec706038 RCX: 00007f75ec575b59 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000004 RBP: 00007f75ec5e4e5d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007f75ec706038 R15: 00007ffef2866ed8 </TASK> PM: Image not found (code -6) --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
