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Date: Thu, 24 Sep 2015 10:51:36 +0200
From: Jens Gustedt <Jens.Gustedt@...ia.fr>
To: musl@...ts.openwall.com
Subject: [PATCH] help static analysis by avoiding to hold state in a pointer
 that is subject to arithmetic

---
 src/thread/pthread_create.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index e7df34a..c00c3fe 100644
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -181,7 +181,7 @@ int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict att
 	int ret, c11 = (attrp == __ATTRP_C11_THREAD);
 	size_t size, guard;
 	struct pthread *self, *new;
-	unsigned char *map = 0, *stack = 0, *tsd = 0, *stack_limit;
+	unsigned char *map = 0, *stack = 0, *tsd, *stack_limit;
 	unsigned flags = CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND
 		| CLONE_THREAD | CLONE_SYSVSEM | CLONE_SETTLS
 		| CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID | CLONE_DETACHED;
@@ -218,6 +218,7 @@ int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict att
 			tsd = stack - __pthread_tsd_size;
 			stack = tsd - libc.tls_size;
 			memset(stack, 0, need);
+			goto setup;
 		} else {
 			size = ROUND(need);
 			guard = 0;
@@ -228,26 +229,25 @@ int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict att
 			+ libc.tls_size +  __pthread_tsd_size);
 	}
 
-	if (!tsd) {
-		if (guard) {
-			map = __mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANON, -1, 0);
-			if (map == MAP_FAILED) goto fail;
-			if (__mprotect(map+guard, size-guard, PROT_READ|PROT_WRITE)
-			    && errno != ENOSYS) {
-				__munmap(map, size);
-				goto fail;
-			}
-		} else {
-			map = __mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
-			if (map == MAP_FAILED) goto fail;
-		}
-		tsd = map + size - __pthread_tsd_size;
-		if (!stack) {
-			stack = tsd - libc.tls_size;
-			stack_limit = map + guard;
+	if (guard) {
+		map = __mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANON, -1, 0);
+		if (map == MAP_FAILED) goto fail;
+		if (__mprotect(map+guard, size-guard, PROT_READ|PROT_WRITE)
+		    && errno != ENOSYS) {
+			__munmap(map, size);
+			goto fail;
 		}
+	} else {
+		map = __mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
+		if (map == MAP_FAILED) goto fail;
+	}
+	tsd = map + size - __pthread_tsd_size;
+	if (!stack) {
+		stack = tsd - libc.tls_size;
+		stack_limit = map + guard;
 	}
 
+setup:
 	new = __copy_tls(tsd - libc.tls_size);
 	new->map_base = map;
 	new->map_size = size;
-- 
2.1.4

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