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Date: Sat, 16 Feb 2013 00:23:39 +0100
From: Jens Gustedt <>
Subject: [PATCH 2/5] Clarify the implementation of the dummy alias used for

In fact this points to a readonly location that is meant to crash the
executable if pthread_keys are used without having properly linked to
pthread_key_create. This can be of the correct type now.

7	4	src/thread/pthread_self.c

diff --git a/src/thread/pthread_self.c b/src/thread/pthread_self.c
index 23dbaa5..87158a7 100644
--- a/src/thread/pthread_self.c
+++ b/src/thread/pthread_self.c
@@ -2,9 +2,12 @@
 static struct pthread *main_thread = &(struct pthread){0};
-/* pthread_key_create.c overrides this */
-static const void *dummy[1] = { 0 };
-weak_alias(dummy, __pthread_tsd_main);
+/* pthread_key_create.c overrides this with a modifiable array
+   whenever the executable is linked with pthread_key_create. If it is
+   not, and an attempt is made to write to the pthread_key system, the
+   program will crash, since this is in a read-only segment. */
+_Readonly_alias void* __pthread_tsd_main[PTHREAD_KEYS_MAX];
 static int init_main_thread()
@@ -12,7 +15,7 @@ static int init_main_thread()
 	if (__set_thread_area(TP_ADJ(main_thread)) < 0) return -1;
 	main_thread->canceldisable = libc.canceldisable;
-	main_thread->tsd = (void **)__pthread_tsd_main;
+	main_thread->tsd = __pthread_tsd_main;
 	main_thread->errno_ptr = __errno_location();
 	main_thread->self = main_thread;
 	main_thread->tid = main_thread->pid =

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