Fix release fence ordering in inner_enqueue() to prevent size_approx() race on AArch64 - #172

cppmage wants to merge 2 commits into

Fix release fence ordering in inner_enqueue() to prevent size_approx() race on AArch64#172
cppmage wants to merge 2 commits into
cameron314:masterfrom
cppmage:cppmage-fix-tailblock-next-race

fix: move release fence in inner_enqueue()