Re: main [and, likely, stable/14]: do not set vfs.zfs.bclone_enabled=1 with that zpool feature enabled because it still leads to panics

On 08.09.2023 09:52, Martin Matuska wrote:
> I digged a little and was able to reproduce the panic without poudriere 
> with a shell script.
> 
> #!/bin/sh
> nl='
> '
> sed_script=s/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb/
> for ac_i in 1 2 3 4 5 6 7; do
>      sed_script="$sed_script$nl$sed_script"
> done
> echo "$sed_script" 2>/dev/null | sed 99q >conftest.sed
> 
> repeats=8
> count=0
> echo -n 0123456789 >"conftest.in"
> while :
> do
>      cat "conftest.in" "conftest.in" >"conftest.tmp"
>      mv "conftest.tmp" "conftest.in"
>      cp "conftest.in" "conftest.nl"
>      echo '' >> "conftest.nl"
>      sed -f conftest.sed < "conftest.nl" >"conftest.out" 2>/dev/null || 
> break
>      diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
>      count=$(($count + 1))
>      echo "count: $count"
>      # 10*(2^10) chars as input seems more than enough
>      test $count -gt $repeats && break
> done
> rm -f conftest.in conftest.tmp conftest.nl conftest.out

Thank you, Martin.  I was able to reproduce the issue with your script 
and found the cause.

I first though the issue is triggered by the `cp`, but it appeared to be 
triggered by `cat`.  It also got copy_file_range() support, but later 
than `cp`.  That is probably why it slipped through testing.  This patch 
fixes it for me: https://github.com/openzfs/zfs/pull/15251 .

Mark, could you please try the patch?

-- 
Alexander Motin