Hello, syzbot found the following issue on: HEAD commit: 45a3e24f65e9 Linux 6.4-rc7 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=12c15540a80000 kernel config: https://syzkaller.appspot.com/x/.config?x=2cbd298d0aff1140 dashboard link: https://syzkaller.appspot.com/bug?extid=2bf8c3b6bedb88990d40 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/872a8054b07c/disk-45a3e24f.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/329227d8d5e9/vmlinux-45a3e24f.xz kernel image: https://storage.googleapis.com/syzbot-assets/e6e7d7b9074e/bzImage-45a3e24f.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+2bf8c3b6bedb88990d40@xxxxxxxxxxxxxxxxxxxxxxxxx ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 5056 at lib/refcount.c:28 refcount_warn_saturate+0x107/0x1f0 lib/refcount.c:28 Modules linked in: CPU: 1 PID: 5056 Comm: syz-executor.4 Not tainted 6.4.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 RIP: 0010:refcount_warn_saturate+0x107/0x1f0 lib/refcount.c:28 Code: 1d c4 8b 51 0a 31 ff 89 de e8 f5 ef 70 fd 84 db 75 a3 e8 0c f4 70 fd 48 c7 c7 c0 d6 a6 8a c6 05 a4 8b 51 0a 01 e8 49 af 38 fd <0f> 0b eb 87 e8 f0 f3 70 fd 0f b6 1d 8d 8b 51 0a 31 ff 89 de e8 c0 RSP: 0018:ffffc900042cfa60 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff8880286bbb80 RSI: ffffffff814c03b7 RDI: 0000000000000001 RBP: ffff8880275112f8 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000082828 R12: ffff88802b4cf300 R13: ffff8880275112f8 R14: ffff888027511308 R15: ffff8880275111c8 FS: 0000555556773400(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcf1bad56be CR3: 000000003f591000 CR4: 0000000000350ee0 Call Trace: <TASK> __refcount_sub_and_test include/linux/refcount.h:283 [inline] __refcount_dec_and_test include/linux/refcount.h:315 [inline] refcount_dec_and_test include/linux/refcount.h:333 [inline] __btrfs_release_delayed_node.part.0+0xb3b/0xf50 fs/btrfs/delayed-inode.c:263 __btrfs_release_delayed_node fs/btrfs/delayed-inode.c:251 [inline] btrfs_release_delayed_node fs/btrfs/delayed-inode.c:281 [inline] btrfs_remove_delayed_node+0x52/0x60 fs/btrfs/delayed-inode.c:1285 btrfs_evict_inode+0x4f4/0xe50 fs/btrfs/inode.c:5336 evict+0x2ed/0x6b0 fs/inode.c:665 dispose_list+0x117/0x1e0 fs/inode.c:698 evict_inodes+0x345/0x440 fs/inode.c:748 generic_shutdown_super+0xaf/0x480 fs/super.c:479 kill_anon_super+0x3a/0x60 fs/super.c:1107 btrfs_kill_super+0x3c/0x50 fs/btrfs/super.c:2144 deactivate_locked_super+0x98/0x160 fs/super.c:331 deactivate_super+0xb1/0xd0 fs/super.c:362 cleanup_mnt+0x2ae/0x3d0 fs/namespace.c:1177 task_work_run+0x16f/0x270 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x210/0x240 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f4b5f28d7f7 Code: ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd5b600188 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f4b5f28d7f7 RDX: 00007ffd5b60025c RSI: 000000000000000a RDI: 00007ffd5b600250 RBP: 00007ffd5b600250 R08: 00000000ffffffff R09: 00007ffd5b600020 R10: 0000555556774893 R11: 0000000000000246 R12: 00007f4b5f2d643b R13: 00007ffd5b601310 R14: 0000555556774810 R15: 00007ffd5b601350 </TASK> --- 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 bug is already fixed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to change bug's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the bug is a duplicate of another bug, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
