Hi just checking why this was still open - I see that the jessie tree now contains the patch 'libmultipath: use a shared lock to co-operate with udev' and is tagged 0.5.0-6+deb8u3. But it seems to have missed the 8.10 point release, and is not lurking in jessie-proposed-updates; 0.5.0-6+deb8u2 is the latest available for jessie.
Does something need a nudge? AFAICT this would close #799781 and #843953 Cheers Vince --