linux-kernel - Re: [syzbot] [gfs2?] kernel BUG in gfs2_jindex

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Message-ID: <68a65f4b.050a0220.3d78fd.000f.GAE@google.com>
Date: Wed, 20 Aug 2025 16:50:35 -0700
From: syzbot <syzbot+150563285f78ac3e9bd4@...kaller.appspotmail.com>
To: agruenba@...hat.com, gfs2@...ts.linux.dev, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [gfs2?] kernel BUG in gfs2_jindex_free (2)

syzbot has found a reproducer for the following issue on:

HEAD commit:    5303936d609e Add linux-next specific files for 20250820
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16775442580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4602df3fd8f406ec
dashboard link: https://syzkaller.appspot.com/bug?extid=150563285f78ac3e9bd4
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=17e597a2580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/57c3527e418a/disk-5303936d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7f1e146ea30f/vmlinux-5303936d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/55bebb5dd947/bzImage-5303936d.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/5e2270ee146f/mount_0.gz
  fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=159c16f0580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+150563285f78ac3e9bd4@...kaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at fs/gfs2/super.c:76!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 7296 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:gfs2_jindex_free+0x43e/0x440 fs/gfs2/super.c:76
Code: cc cc cc cc cc 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c ea fd ff ff e8 22 e7 25 fe e9 e0 fd ff ff e8 88 e4 7f 07 e8 b3 1f c2 fd 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00
RSP: 0018:ffffc9000b737a40 EFLAGS: 00010293
RAX: ffffffff83fda7cd RBX: dead000000000122 RCX: ffff88802c6c9e00
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 00000000ffffffff
RBP: ffffc9000b737b00 R08: ffff888078520de7 R09: 1ffff1100f0a41bc
R10: dffffc0000000000 R11: ffffed100f0a41bd R12: ffff8880785208b0
R13: dffffc0000000000 R14: ffff888033122800 R15: ffff888033122878
FS:  0000000000000000(0000) GS:ffff888125a05000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff329e51000 CR3: 0000000030646000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 gfs2_put_super+0x8af/0x950 fs/gfs2/super.c:636
 generic_shutdown_super+0x132/0x2c0 fs/super.c:643
 kill_block_super+0x44/0x90 fs/super.c:1723
 deactivate_locked_super+0xbc/0x130 fs/super.c:474
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1375
 task_work_run+0x1d1/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x6b5/0x2300 kernel/exit.c:961
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1111
 x64_sys_call+0x21f7/0x2200 arch/x86/include/generated/asm/syscalls_64.h:232
 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: 0033:0x7fed18f8ebe9
Code: Unable to access opcode bytes at 0x7fed18f8ebbf.
RSP: 002b:00007ffc2c3ee178 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fed19011c2a RCX: 00007fed18f8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000005 R08: 00007ffc2c3ebf17 R09: 00007ffc2c3ef3d0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc2c3ef3d0
R13: 00007fed19011c05 R14: 0000000000053df0 R15: 00007ffc2c3ef410
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:gfs2_jindex_free+0x43e/0x440 fs/gfs2/super.c:76
Code: cc cc cc cc cc 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c ea fd ff ff e8 22 e7 25 fe e9 e0 fd ff ff e8 88 e4 7f 07 e8 b3 1f c2 fd 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00
RSP: 0018:ffffc9000b737a40 EFLAGS: 00010293
RAX: ffffffff83fda7cd RBX: dead000000000122 RCX: ffff88802c6c9e00
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 00000000ffffffff
RBP: ffffc9000b737b00 R08: ffff888078520de7 R09: 1ffff1100f0a41bc
R10: dffffc0000000000 R11: ffffed100f0a41bd R12: ffff8880785208b0
R13: dffffc0000000000 R14: ffff888033122800 R15: ffff888033122878
FS:  0000000000000000(0000) GS:ffff888125b05000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fece4332000 CR3: 00000000584a4000 CR4: 00000000003526f0


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.