Don't enqueue pending signals during global destruction

Global destruction is not signal-safe. PL_psig_pend may already
be gone when the signal handler is called (with destruct_level > 0).
NULL it before freeing it to prevent a race condition.

1 files changed, 7 insertions, 0 deletions

diff --git a/perl.c b/perl.c
index e70bf7e4e3..d9ebaca07b 100644
--- a/perl.c
+++ b/perl.c
@@ -1233,6 +1233,13 @@ perl_destruct(pTHXx)
     PL_psig_ptr = (SV**)NULL;
     Safefree(PL_psig_pend);
     PL_psig_pend = (int*)NULL;
+    {
+	/* We need to NULL PL_psig_pend first, so that
+	   signal handlers know not to use it */
+	int *psig_save = PL_psig_pend;
+	PL_psig_pend = (int*)NULL;
+	Safefree(psig_save);
+    }
     PL_formfeed = NULL;
     nuke_stacks();
     PL_tainting = FALSE;