17aa39da50
Commit 4518c798 intended to block signals in regular backends that allocate DSM segments, but dsm_impl_resize() is also reached by dsm_postmaster_startup(). It's not OK to clobber the postmaster's signal mask, so only manipulate the signal mask when under the postmaster. Back-patch to all releases, like 4518c798. Discussion: https://postgr.es/m/CA%2BhUKGKNpK%3D2OMeea_AZwpLg7Bm4%3DgYWk7eDjZ5F6YbozfOf8w%40mail.gmail.com