Re: [syzbot] [gfs2?] kernel BUG in gfs2_jindex_free (2)

On 13/06/2025 12:37, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    19272b37aa4f Linux 6.16-rc1
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=108dca82580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c07f08ee4bcfb276
> dashboard link: https://syzkaller.appspot.com/bug?extid=150563285f78ac3e9bd4

It looks like this was fixed by bb47cce7a1 "gfs2: gfs2_log_flush withdraw fixes" which also took care of generic/753.

#syz fix: gfs2: gfs2_log_flush withdraw fixes

Andy

> compiler:       Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
> 
> 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-19272b37.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/b70bcabfccd8/vmlinux-19272b37.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/57e93b736a7a/bzImage-19272b37.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email protected]
> 
> loop0: detected capacity change from 0 to 1024
> hfsplus: failed to load root directory
> 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 1 extents in 0ms
> gfs2: fsid=syz:syz.0: first mount done, others may mount
> gfs2: fsid=syz:syz.0: fatal: I/O error - block = 9377, function = gfs2_ail1_empty_one, file = fs/gfs2/log.c, line = 328
> gfs2: fsid=syz:syz.0: about to withdraw this file system
> gfs2: fsid=syz:syz.0: Journal recovery skipped for jid 0 until next mount.
> gfs2: fsid=syz:syz.0: Glock dequeues delayed: 0
> gfs2: fsid=syz:syz.0: File system withdrawn
> CPU: 0 UID: 0 PID: 5325 Comm: syz.0.0 Not tainted 6.16.0-rc1-syzkaller #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
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
>  gfs2_withdraw+0x111e/0x14f0 fs/gfs2/util.c:354
>  revoke_lo_before_commit+0x2f/0xe60 fs/gfs2/lops.c:857
>  lops_before_commit fs/gfs2/lops.h:42 [inline]
>  gfs2_log_flush+0xb8b/0x24c0 fs/gfs2/log.c:1105
>  gfs2_sync_fs+0x6d/0xb0 fs/gfs2/super.c:662
>  sync_filesystem+0x1cf/0x230 fs/sync.c:66
>  gfs2_reconfigure+0xbb/0xb20 fs/gfs2/ops_fstype.c:1555
>  reconfigure_super+0x224/0x890 fs/super.c:1075
>  vfs_cmd_reconfigure fs/fsopen.c:262 [inline]
>  vfs_fsconfig_locked+0x171/0x320 fs/fsopen.c:291
>  __do_sys_fsconfig fs/fsopen.c:467 [inline]
>  __se_sys_fsconfig+0x78e/0x8d0 fs/fsopen.c:344
>  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: 0033:0x7f3a8ed8e929
> 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:00007f3a8fb52038 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
> RAX: ffffffffffffffda RBX: 00007f3a8efb5fa0 RCX: 00007f3a8ed8e929
> RDX: 0000000000000000 RSI: 0000000000000007 RDI: 000000000000000c
> RBP: 00007f3a8ee10b39 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 0000000000000000 R14: 00007f3a8efb5fa0 R15: 00007fff7917f738
>  </TASK>
> ------------[ cut here ]------------
> kernel BUG at fs/gfs2/super.c:76!
> Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
> CPU: 0 UID: 0 PID: 5325 Comm: syz.0.0 Not tainted 6.16.0-rc1-syzkaller #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_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 52 d1 2b fe e9 e0 fd ff ff e8 08 02 6e 07 e8 13 59 c8 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:ffffc9000fec7800 EFLAGS: 00010293
> RAX: ffffffff83f805dd RBX: dead000000000122 RCX: ffff888000514880
> RDX: 0000000000000000 RSI: 0000000000000008 RDI: 00000000ffffffff
> RBP: ffffc9000fec78c0 R08: ffff888042458d4f R09: 1ffff1100848b1a9
> R10: dffffc0000000000 R11: ffffed100848b1aa R12: ffff888042458818
> R13: dffffc0000000000 R14: ffff888035c49400 R15: ffff888035c49478
> FS:  0000000000000000(0000) GS:ffff88808d252000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000055c2ed7e1b88 CR3: 0000000011bd9000 CR4: 0000000000352ef0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  gfs2_put_super+0x8af/0x950 fs/gfs2/super.c:638
>  generic_shutdown_super+0x135/0x2c0 fs/super.c:643
>  kill_block_super+0x44/0x90 fs/super.c:1753
>  deactivate_locked_super+0xb9/0x130 fs/super.c:474
>  cleanup_mnt+0x425/0x4c0 fs/namespace.c:1417
>  task_work_run+0x1d1/0x260 kernel/task_work.c:227
>  exit_task_work include/linux/task_work.h:40 [inline]
>  do_exit+0x6ad/0x22e0 kernel/exit.c:955
>  do_group_exit+0x21c/0x2d0 kernel/exit.c:1104
>  get_signal+0x1286/0x1340 kernel/signal.c:3034
>  arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
>  exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:111
>  exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
>  syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
>  syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
>  do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f3a8ed8e929
> Code: Unable to access opcode bytes at 0x7f3a8ed8e8ff.
> RSP: 002b:00007f3a8fb52038 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
> RAX: fffffffffffffffb RBX: 00007f3a8efb5fa0 RCX: 00007f3a8ed8e929
> RDX: 0000000000000000 RSI: 0000000000000007 RDI: 000000000000000c
> RBP: 00007f3a8ee10b39 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 0000000000000000 R14: 00007f3a8efb5fa0 R15: 00007fff7917f738
>  </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 52 d1 2b fe e9 e0 fd ff ff e8 08 02 6e 07 e8 13 59 c8 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:ffffc9000fec7800 EFLAGS: 00010293
> RAX: ffffffff83f805dd RBX: dead000000000122 RCX: ffff888000514880
> RDX: 0000000000000000 RSI: 0000000000000008 RDI: 00000000ffffffff
> RBP: ffffc9000fec78c0 R08: ffff888042458d4f R09: 1ffff1100848b1a9
> R10: dffffc0000000000 R11: ffffed100848b1aa R12: ffff888042458818
> R13: dffffc0000000000 R14: ffff888035c49400 R15: ffff888035c49478
> FS:  0000000000000000(0000) GS:ffff88808d252000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000055c2ed7e1b88 CR3: 00000000122c6000 CR4: 0000000000352ef0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> 
> 
> ---
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