MariaBackup prepare crashes with invalid pointer with compression providers and extra options

free(): invalid pointer

211008 21:33:40 [ERROR] mysqld got signal 6 ;

#3  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50

#4  0x00007f170cb7a859 in __GI_abort () at abort.c:79

#5  0x00007f170cbe53ee in __libc_message (action=action@entry=do_abort, fmt=fmt@entry=0x7f170cd0f285 "%s\n") at ../sysdeps/posix/libc_fatal.c:155

#6  0x00007f170cbed47c in malloc_printerr (str=str@entry=0x7f170cd0d4ae "free(): invalid pointer") at malloc.c:5347

#7  0x00007f170cbeecac in _int_free (av=<optimized out>, p=<optimized out>, have_lock=0) at malloc.c:4173

#8  0x000055a7dff5cce5 in msg1(uint, const char *, const char *, typedef __va_list_tag __va_list_tag *) (thread_num=0, prefix=0x55a7e0e55e71 "", fmt=0x55a7e0e5c458 "This target seems to be not prepared yet.", args=0x7ffda92170e8) at /data/src/preview-10.7-MDEV-12933-provider-plugins-deb/extra/mariabackup/common.h:102

#9  0x000055a7dff5ce61 in msg (fmt=0x55a7e0e5c458 "This target seems to be not prepared yet.") at /data/src/preview-10.7-MDEV-12933-provider-plugins-deb/extra/mariabackup/common.h:122

#10 0x000055a7dff6c5ed in xtrabackup_prepare_func (argv=0x55a7e40fb508) at /data/src/preview-10.7-MDEV-12933-provider-plugins-deb/extra/mariabackup/xtrabackup.cc:5803

#11 0x000055a7dff6f2f8 in main_low (argv=0x55a7e40fb508) at /data/src/preview-10.7-MDEV-12933-provider-plugins-deb/extra/mariabackup/xtrabackup.cc:6793

#12 0x000055a7dff6eb29 in main (argc=4, argv=0x7ffda9217bf8) at /data/src/preview-10.7-MDEV-12933-provider-plugins-deb/extra/mariabackup/xtrabackup.cc:6591

--source include/have_innodb.inc

install soname 'provider_lzma';

set global innodb_compression_algorithm = lzma;

create table t1 (a int, b text) engine = innodb page_compressed=yes;

insert t1 (a, b) values (0, repeat("abc", 100));

let $targetdir=$MYSQLTEST_VARDIR/tmp/backup;

exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --target-dir=$targetdir;

--disable_abort_on_error

exec $XTRABACKUP --prepare --target-dir=$targetdir --use-memory=128M > $MYSQLTEST_VARDIR/tmp/prepare.log 2>&1;

cat_file $MYSQLTEST_VARDIR/tmp/prepare.log;