Re: [syzbot] Monthly btrfs report (Feb 2024)

[Aleksandr Nogikh]

Hi,

It looks like existing reproducers for this bug began to fail after
CONFIG_BLK_DEV_WRITE_MOUNTED reached torvalds and syzbot has not found
a newer reproducer since then (though it does hit the bug, so it must
be possible even with CONFIG_BLK_DEV_WRITE_MOUNTED=n).

I was was able to reproduce it locally using the older kernel revision
built by syzbot:
https://gist.github.com/a-nogikh/f68aa687a72aad4bb46a64d995c2415f
FWIW here are the docs:
https://github.com/google/syzkaller/blob/master/docs/syzbot_assets.md

-- 
Aleksandr

On Sat, Feb 10, 2024 at 9:48 AM 'Qu Wenruo' via syzkaller-bugs
<syzkaller-bugs@xxxxxxxxxxxxxxxx> wrote:
>
> >
> > Ref  Crashes Repro Title
> > <1>  5804    Yes   kernel BUG in close_ctree
> >                     https://syzkaller.appspot.com/bug?extid=2665d678fffcc4608e18
>
> I'm not sure why, but I never had a good experience reproducing the bug
> using the C reproduer.
>
> Furthermore, for this particular case, using that C reproducer only
> reduced tons of duplicated dmesg of:
>
> [  162.264838] btrfs: Unknown parameter 'noinode_cache'
> [  162.308573] loop0: detected capacity change from 0 to 32768
> [  162.308964] btrfs: Unknown parameter 'noinode_cache'
> [  162.313582] loop1: detected capacity change from 0 to 32768
> [  162.314070] btrfs: Unknown parameter 'noinode_cache'
> [  162.323629] loop3: detected capacity change from 0 to 32768
> [  162.324000] btrfs: Unknown parameter 'noinode_cache'
> [  162.328046] loop2: detected capacity change from 0 to 32768
> [  162.328417] btrfs: Unknown parameter 'noinode_cache'
>
> Unlike the latest report which shows a lot of other things.
>
> Anyone can help verifying the C reproducer?
> Or I'm doing something wrong withe the reproducer?
>
> Thanks,
> Qu
> > <2>  2636    Yes   WARNING in btrfs_space_info_update_bytes_may_use
> >                     https://syzkaller.appspot.com/bug?extid=8edfa01e46fd9fe3fbfb
> > <3>  251     Yes   INFO: task hung in lock_extent
> >                     https://syzkaller.appspot.com/bug?extid=eaa05fbc7563874b7ad2
> > <4>  245     Yes   WARNING in btrfs_chunk_alloc
> >                     https://syzkaller.appspot.com/bug?extid=e8e56d5d31d38b5b47e7
> > <5>  224     Yes   WARNING in btrfs_remove_chunk
> >                     https://syzkaller.appspot.com/bug?extid=e8582cc16881ec70a430
> > <6>  125     Yes   kernel BUG in insert_state_fast
> >                     https://syzkaller.appspot.com/bug?extid=9ce4a36127ca92b59677
> > <7>  99      Yes   kernel BUG in btrfs_free_tree_block
> >                     https://syzkaller.appspot.com/bug?extid=a306f914b4d01b3958fe
> > <8>  88      Yes   kernel BUG in set_state_bits
> >                     https://syzkaller.appspot.com/bug?extid=b9d2e54d2301324657ed
> > <9>  79      Yes   WARNING in btrfs_commit_transaction (2)
> >                     https://syzkaller.appspot.com/bug?extid=dafbca0e20fbc5946925
> > <10> 74      Yes   WARNING in btrfs_put_transaction
> >                     https://syzkaller.appspot.com/bug?extid=3706b1df47f2464f0c1e
> >
> > ---
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> > See https://goo.gl/tpsmEJ for more information about syzbot.
> > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx.
> >
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> >
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>