realign ucontext stack after #6719

diff --git a/pdns/mtasker_ucontext.cc b/pdns/mtasker_ucontext.cc
index d7663e340ba967aecd4f0ea97e9472323b0b5539..2cecc97f4a18b28f3e3291f1a345d5749a95d98f 100644 (file)
--- a/pdns/mtasker_ucontext.cc
+++ b/pdns/mtasker_ucontext.cc
@@ -134,7 +134,7 @@ pdns_makecontext
     }
     mcp->uc_link = next;
     mcp->uc_stack.ss_sp = ctx.uc_stack.data();
-    mcp->uc_stack.ss_size = ctx.uc_stack.size();
+    mcp->uc_stack.ss_size = ctx.uc_stack.size()-1;
     mcp->uc_stack.ss_flags = 0;
 
     auto ctxarg = splitPointer (&ctx);