Re: [syzbot] [gfs2?] kernel BUG in do_qc

[syzbot <syzbot+bad65435361712796381@syzkaller.appspotmail.com>]

syzbot has found a reproducer for the following issue on:

HEAD commit:    eacf91b0c78a Merge tag 'fbdev-for-6.17-rc1' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=162a3834580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=bbdefbf39cb79f7e
dashboard link: https://syzkaller.appspot.com/bug?extid=bad65435361712796381
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10c03cf0580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=112a3834580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-eacf91b0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/51416a3bb992/vmlinux-eacf91b0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/aa2684a00ab0/bzImage-eacf91b0.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/d4ede27f2613/mount_1.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=151c7f82580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bad65435361712796381@syzkaller.appspotmail.com

gfs2: fsid=syz:syz.0: first mount done, others may mount
gfs2: fsid=syz:syz.0: found 1 quota changes
gfs2: fsid=syz:syz.0: fatal assertion failed
------------[ cut here ]------------
kernel BUG at fs/gfs2/quota.c:320!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5780 Comm: syz.0.38 Not tainted 6.16.0-syzkaller-11129-geacf91b0c78a #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:__qd_hold fs/gfs2/quota.c:320 [inline]
RIP: 0010:do_qc+0x5c1/0x5e0 fs/gfs2/quota.c:705
Code: 00 00 00 00 00 fc ff df 48 8b 0c 24 80 3c 01 00 74 0a 48 8b 7c 24 10 e8 bd fd 28 fe 48 8b 44 24 10 48 8b 38 e8 70 e2 2e fd 90 <0f> 0b e8 f8 2b c4 fd 48 8b 7c 24 10 e8 5e e2 2e fd 90 0f 0b 66 66
RSP: 0018:ffffc9000d68f348 EFLAGS: 00010246
RAX: 000000000000002c RBX: 1ffff1100860680e RCX: 05e99f5eed550400
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffffc9000d68f067 R09: 1ffff92001ad1e0c
R10: dffffc0000000000 R11: fffff52001ad1e0d R12: ffff888043034000
R13: ffff888043034070 R14: ffff888043034090 R15: 0000000000000000
FS:  00007faa59d406c0(0000) GS:ffff88808d21f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb33a2f7000 CR3: 000000003f713000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 gfs2_quota_change+0x394/0x800 fs/gfs2/quota.c:1304
 gfs2_alloc_blocks+0x18bc/0x2080 fs/gfs2/rgrp.c:2494
 alloc_dinode+0x258/0x550 fs/gfs2/inode.c:422
 gfs2_create_inode+0xbbc/0x1560 fs/gfs2/inode.c:807
 gfs2_atomic_open+0xd2/0x220 fs/gfs2/inode.c:1395
 atomic_open fs/namei.c:3568 [inline]
 lookup_open fs/namei.c:3679 [inline]
 open_last_lookups fs/namei.c:3807 [inline]
 path_openat+0xf63/0x3830 fs/namei.c:4043
 do_filp_open+0x1fa/0x410 fs/namei.c:4073
 do_sys_openat2+0x121/0x1c0 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1461
 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: 0033:0x7faa58f8eb69
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:00007faa59d40038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007faa591b5fa0 RCX: 00007faa58f8eb69
RDX: 0000000000105042 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007faa59011df1 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000001ff R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007faa591b5fa0 R15: 00007ffdf5ca1658
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__qd_hold fs/gfs2/quota.c:320 [inline]
RIP: 0010:do_qc+0x5c1/0x5e0 fs/gfs2/quota.c:705
Code: 00 00 00 00 00 fc ff df 48 8b 0c 24 80 3c 01 00 74 0a 48 8b 7c 24 10 e8 bd fd 28 fe 48 8b 44 24 10 48 8b 38 e8 70 e2 2e fd 90 <0f> 0b e8 f8 2b c4 fd 48 8b 7c 24 10 e8 5e e2 2e fd 90 0f 0b 66 66
RSP: 0018:ffffc9000d68f348 EFLAGS: 00010246
RAX: 000000000000002c RBX: 1ffff1100860680e RCX: 05e99f5eed550400
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffffc9000d68f067 R09: 1ffff92001ad1e0c
R10: dffffc0000000000 R11: fffff52001ad1e0d R12: ffff888043034000
R13: ffff888043034070 R14: ffff888043034090 R15: 0000000000000000
FS:  00007faa59d406c0(0000) GS:ffff88808d21f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb33a2f7000 CR3: 000000003f713000 CR4: 0000000000352ef0


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#syz test: git://repo/address.git branch-or-commit-hash
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