Message-ID: <8847edf3-abb6-4efd-8f19-77663556da33@redhat.com>
Date: Mon, 18 Aug 2025 13:43:59 +0100
From: Andrew Price <anprice@...hat.com>
To: syzbot <syzbot+901524eae72170197041@...kaller.appspotmail.com>,
 agruenba@...hat.com, gfs2@...ts.linux.dev, linux-kernel@...r.kernel.org,
 syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [gfs2?] kernel BUG in gfs2_withdraw (2)

On 17/08/2025 18:58, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    8742b2d8935f Merge tag 'pull-fixes' of git://git.kernel.or..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=1414cda2580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=d67d3af29f50297e
> dashboard link: https://syzkaller.appspot.com/bug?extid=901524eae72170197041
> compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-8742b2d8.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/b561d09cce5a/vmlinux-8742b2d8.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/0eac1e9113b1/bzImage-8742b2d8.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+901524eae72170197041@...kaller.appspotmail.com
> 
> loop0: detected capacity change from 0 to 32768
> gfs2: fsid=syz:syz: Trying to join cluster "lock_nolock", "syz:syz"
> gfs2: fsid=syz:syz: Now mounting FS (format 1801)...
> gfs2: fsid=syz:syz.0: journal 0 mapped with 5 extents in 0ms
> gfs2: fsid=syz:syz.0: first mount done, others may mount
> gfs2: fsid=syz:syz.0: fatal: invalid metadata block - bh = 2051 (type: exp=14, found=8), function = gfs2_quota_init, file = fs/gfs2/quota.c, line = 1430
> gfs2: fsid=syz:syz.0: about to withdraw this file system
> ------------[ cut here ]------------
> kernel BUG at fs/gfs2/util.c:331!

That's strange, this should have been prevented by this syzbot fix:

https://github.com/google/syzkaller/commit/338f25e2408a360bd3af7f03091b1cbda0887a52

Perhaps it hasn't gone live yet?

Andy

> Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
> CPU: 0 UID: 0 PID: 5364 Comm: syz.0.0 Not tainted 6.17.0-rc1-syzkaller-00016-g8742b2d8935f #0 PREEMPT(full) 
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
> RIP: 0010:gfs2_withdraw+0x137b/0x1430 fs/gfs2/util.c:331
> Code: ff ff 48 8b 4c 24 18 80 e1 07 80 c1 03 38 c1 0f 8c 55 fb ff ff 48 8b 7c 24 18 e8 20 7c 25 fe e9 46 fb ff ff e8 86 90 c0 fd 90 <0f> 0b 48 8b 4c 24 18 80 e1 07 80 c1 03 38 c1 0f 8c ab fb ff ff 48
> RSP: 0018:ffffc9000d32f680 EFLAGS: 00010293
> RAX: ffffffff83ff2ada RBX: ffffc9000d32f740 RCX: ffff888000aa0000
> RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000
> RBP: ffffc9000d32f810 R08: ffff88801fc24253 R09: 1ffff11003f8484a
> R10: dffffc0000000000 R11: ffffed1003f8484b R12: dffffc0000000000
> R13: 1ffff92001a65ee4 R14: 1ffff110087b3815 R15: 0000000000000004
> FS:  00007fc82060a6c0(0000) GS:ffff88808d211000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fdc3a1909c0 CR3: 0000000042f3e000 CR4: 0000000000352ef0
> Call Trace:
>  <TASK>
>  gfs2_metatype_check_ii+0x78/0x90 fs/gfs2/util.c:514
>  gfs2_metatype_check_i fs/gfs2/util.h:129 [inline]
>  gfs2_quota_init+0xfc8/0x1230 fs/gfs2/quota.c:1430
>  gfs2_make_fs_rw+0x181/0x2b0 fs/gfs2/super.c:149
>  gfs2_fill_super+0x1a7b/0x20d0 fs/gfs2/ops_fstype.c:1278
>  get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1692
>  gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1335
>  vfs_get_tree+0x8f/0x2b0 fs/super.c:1815
>  do_new_mount+0x2a2/0x9e0 fs/namespace.c:3805
>  do_mount fs/namespace.c:4133 [inline]
>  __do_sys_mount fs/namespace.c:4344 [inline]
>  __se_sys_mount+0x317/0x410 fs/namespace.c:4321
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7fc81f79038a
> Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007fc820609e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
> RAX: ffffffffffffffda RBX: 00007fc820609ef0 RCX: 00007fc81f79038a
> RDX: 0000200000000400 RSI: 0000200000012500 RDI: 00007fc820609eb0
> RBP: 0000200000000400 R08: 00007fc820609ef0 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000012500
> R13: 00007fc820609eb0 R14: 00000000000125bb R15: 0000200000000900
>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:gfs2_withdraw+0x137b/0x1430 fs/gfs2/util.c:331
> Code: ff ff 48 8b 4c 24 18 80 e1 07 80 c1 03 38 c1 0f 8c 55 fb ff ff 48 8b 7c 24 18 e8 20 7c 25 fe e9 46 fb ff ff e8 86 90 c0 fd 90 <0f> 0b 48 8b 4c 24 18 80 e1 07 80 c1 03 38 c1 0f 8c ab fb ff ff 48
> RSP: 0018:ffffc9000d32f680 EFLAGS: 00010293
> RAX: ffffffff83ff2ada RBX: ffffc9000d32f740 RCX: ffff888000aa0000
> RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000
> RBP: ffffc9000d32f810 R08: ffff88801fc24253 R09: 1ffff11003f8484a
> R10: dffffc0000000000 R11: ffffed1003f8484b R12: dffffc0000000000
> R13: 1ffff92001a65ee4 R14: 1ffff110087b3815 R15: 0000000000000004
> FS:  00007fc82060a6c0(0000) GS:ffff88808d211000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fdc3a1909c0 CR3: 0000000042f3e000 CR4: 0000000000352ef0
> 
> 
> ---
> 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@...glegroups.com.
> 
> 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
> 

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