This cherry-picks upstream:
commit bba7cbf0a4
Author: Alexander Motin <mav@FreeBSD.org>
Date: Wed Apr 26 12:20:43 2023 -0400
Fix positive ABD size assertion in abd_verify().
Gang ABDs without childred are legal, and they do have zero size.
For other ABD types zero size doesn't have much sense and likely
not working correctly now.
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#14795
Sponsored by: Rubicon Communications, LLC ("Netgate")
d09a955a60