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, 2 insertions, 1 deletions

diff --git a/mg.c b/mg.c
index e9e4214d5a..05a5092b25 100644
--- a/mg.c
+++ b/mg.c
@@ -1316,13 +1316,14 @@ Perl_csighandler(int sig)
 #endif
 	   (PL_signals & PERL_SIGNALS_UNSAFE_FLAG))
 	/* Call the perl level handler now--
-	 * with risk we may be in malloc() etc. */
+	 * with risk we may be in malloc() or being destructed etc. */
 #if defined(HAS_SIGACTION) && defined(SA_SIGINFO)
 	(*PL_sighandlerp)(sig, NULL, NULL);
 #else
 	(*PL_sighandlerp)(sig);
 #endif
     else {
+	if (!PL_psig_pend) return;
 	/* Set a flag to say this signal is pending, that is awaiting delivery after
 	 * the current Perl opcode completes */
 	PL_psig_pend[sig]++;