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From:   Aleksandr Nogikh <nogikh@google.com>
Date:   Mon, 31 Oct 2022 12:02:46 -0700
Message-ID: <CANp29Y7NBk8XrwiuiqiUprPKtShHGaFG4d_P4qn6MnxiHVwhyg@mail.gmail.com>
Subject: Re: [syzbot] WARNING in btrfs_space_info_update_bytes_may_use
To:     syzbot <syzbot+8edfa01e46fd9fe3fbfb@syzkaller.appspotmail.com>
Cc:     clm@fb.com, dsterba@suse.com, josef@toxicpanda.com,
        linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org,
        syzkaller-bugs@googlegroups.com, yin31149@gmail.com
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FWIW there's an attempt to fix a very similarly looking problem
(https://lore.kernel.org/all/0000000000002a909705eb841dda@google.com/)
by Hawkins Jiawei (cc'd):
https://lore.kernel.org/linux-btrfs/20221030162223.25970-1-yin31149@gmail.com/t/

If the bugs are indeed related, we might want to tell the bot to
deduplicate one to another.

On Sun, Oct 30, 2022 at 5:15 PM syzbot
<syzbot+8edfa01e46fd9fe3fbfb@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    b229b6ca5abb Merge tag 'perf-tools-fixes-for-v6.1-2022-10-..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=158eaff6880000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=a66c6c673fb555e8
> dashboard link: https://syzkaller.appspot.com/bug?extid=8edfa01e46fd9fe3fbfb
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17db9ab1880000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=124e21b6880000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/ba5b49fa77de/disk-b229b6ca.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/7c061f2ae4dc/vmlinux-b229b6ca.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/bc45c1300e9b/bzImage-b229b6ca.xz
> mounted in repro: https://storage.googleapis.com/syzbot-assets/17cf7ba1084e/mount_0.gz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+8edfa01e46fd9fe3fbfb@syzkaller.appspotmail.com
>
> BTRFS info (device loop0): enabling ssd optimizations
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 3604 at fs/btrfs/space-info.h:122 btrfs_space_info_update_bytes_may_use+0x524/0x820 fs/btrfs/space-info.h:122
> Modules linked in:
> CPU: 0 PID: 3604 Comm: syz-executor245 Not tainted 6.1.0-rc2-syzkaller-00105-gb229b6ca5abb #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
> RIP: 0010:btrfs_space_info_update_bytes_may_use+0x524/0x820 fs/btrfs/space-info.h:122
> Code: fd e9 77 fb ff ff e8 3b 4b fd fd 4d 89 e6 48 89 de 49 f7 de 4c 89 f7 e8 9a 47 fd fd 49 39 de 0f 86 b5 fc ff ff e8 1c 4b fd fd <0f> 0b 31 db e9 af fc ff ff e8 0e 4b fd fd 48 8d 7d 18 be ff ff ff
> RSP: 0018:ffffc90003f4f9c0 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: 00000000000d0000 RCX: 0000000000000000
> RDX: ffff888021f78000 RSI: ffffffff837f5164 RDI: 0000000000000006
> RBP: ffff88807da53000 R08: 0000000000000006 R09: 00000000000e0000
> R10: 00000000000d0000 R11: 000000000008c07e R12: fffffffffff20000
> R13: ffff88807da53060 R14: 00000000000e0000 R15: 0000000000000002
> FS:  0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007faff6153690 CR3: 000000000bc8e000 CR4: 0000000000350ef0
> Call Trace:
>  <TASK>
>  btrfs_space_info_free_bytes_may_use fs/btrfs/space-info.h:154 [inline]
>  block_rsv_release_bytes fs/btrfs/block-rsv.c:151 [inline]
>  btrfs_block_rsv_release+0x515/0x650 fs/btrfs/block-rsv.c:295
>  btrfs_release_global_block_rsv+0x22/0x2e0 fs/btrfs/block-rsv.c:463
>  btrfs_free_block_groups+0x954/0x1100 fs/btrfs/block-group.c:4051
>  close_ctree+0xd17/0xdc3 fs/btrfs/disk-io.c:4710
>  generic_shutdown_super+0x154/0x410 fs/super.c:491
>  kill_anon_super+0x36/0x60 fs/super.c:1085
>  btrfs_kill_super+0x38/0x50 fs/btrfs/super.c:2441
>  deactivate_locked_super+0x94/0x160 fs/super.c:331
>  deactivate_super+0xad/0xd0 fs/super.c:362
>  cleanup_mnt+0x2ae/0x3d0 fs/namespace.c:1186
>  task_work_run+0x16b/0x270 kernel/task_work.c:179
>  exit_task_work include/linux/task_work.h:38 [inline]
>  do_exit+0xb35/0x2a20 kernel/exit.c:820
>  do_group_exit+0xd0/0x2a0 kernel/exit.c:950
>  __do_sys_exit_group kernel/exit.c:961 [inline]
>  __se_sys_exit_group kernel/exit.c:959 [inline]
>  __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:959
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7f87197f03e9
> Code: Unable to access opcode bytes at 0x7f87197f03bf.
> RSP: 002b:00007ffebfd5c0d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
> RAX: ffffffffffffffda RBX: 00007f871987d470 RCX: 00007f87197f03e9
> RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000001
> RBP: 0000000000000001 R08: ffffffffffffffb8 R09: 00007ffebf003031
> R10: 0000000080000009 R11: 0000000000000246 R12: 00007f871987d470
> R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
>  </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@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches
>
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