[perl #119311] Keep CvDEPTH and savestack in sync

when unwinding sub and format calls.

The comments in the added test file explain what the problem is.

The fix is to call LEAVE_SCOPE in POPSUB and POPFORMAT (to free their
lexicals) before lowering CvDEPTH.

If the context has already been popped via cxstack_ix--, then
LEAVE_SCOPE could overwrite it, so accessing cx after LEAVE_SCOPE is
unsafe.  Hence the changes to POPSUB and POPFORMAT are a bit involved.
Some callers of POPSUB do a temporary cxstack_ix++ first so they
can access cx afterwards.  Two cases needed to be changed to
work that way.

1 files changed, 1 insertions, 1 deletions

diff --git a/pp_hot.c b/pp_hot.c
index ca958301a3..82c8e12a06 100644
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -2510,8 +2510,8 @@ PP(pp_leavesub)
     PUTBACK;
 
     LEAVE;
-    cxstack_ix--;
     POPSUB(cx,sv);	/* Stack values are safe: release CV and @_ ... */
+    cxstack_ix--;
     PL_curpm = newpm;	/* ... and pop $1 et al */
 
     LEAVESUB(sv);