perl/perl-5.17.9-106212-Add-PL_perlio_mutex-to-atfork_lock.patch

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From 4da80956418bbe1fdc23cad0b1cbb24cd7b87609 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Patrik=20H=C3=A4gglund?= <patrik.h.hagglund@ericsson.com>
Date: Sat, 2 Feb 2013 20:21:05 +0100
Subject: [PATCH] PATCH [perl #106212] Add PL_perlio_mutex to
atfork_lock/unlock
Using threads + fork() on Linux, and IO operations in the threads, the
PL_perlio_mutex may be left in a locked state at the call of fork(),
potentially leading to deadlock in the child process at subsequent IO
operations. (Threads are pre-empted and not continued in the child
process after the fork.)
Therefore, ensure that the PL_perlio_mutex is unlocked in the child
process, right after fork(), by using atfork_lock/unlock.
(The RT text gives ways to reproduce the problem, but are not easily
added to Perl's test suite)
---
util.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/util.c b/util.c
index 5c695b8..75381f1 100644
--- a/util.c
+++ b/util.c
@@ -2798,6 +2798,9 @@ Perl_atfork_lock(void)
dVAR;
#if defined(USE_ITHREADS)
/* locks must be held in locking order (if any) */
+# ifdef USE_PERLIO
+ MUTEX_LOCK(&PL_perlio_mutex);
+# endif
# ifdef MYMALLOC
MUTEX_LOCK(&PL_malloc_mutex);
# endif
@@ -2812,6 +2815,9 @@ Perl_atfork_unlock(void)
dVAR;
#if defined(USE_ITHREADS)
/* locks must be released in same order as in atfork_lock() */
+# ifdef USE_PERLIO
+ MUTEX_UNLOCK(&PL_perlio_mutex);
+# endif
# ifdef MYMALLOC
MUTEX_UNLOCK(&PL_malloc_mutex);
# endif
--
1.8.1.4