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authorRich Felker <dalias@aerifal.cx>2018-09-18 23:06:50 -0400
committerRich Felker <dalias@aerifal.cx>2018-09-18 23:06:50 -0400
commit792f32772e64a32527cd455ebfa087ef434a6f4f (patch)
tree529bab8e8047cdd70f64a4113fb4bc1932180964
parentc7ed3e909a69d34a7821f7db644c2fa590a1a690 (diff)
downloadmusl-792f32772e64a32527cd455ebfa087ef434a6f4f.tar.gz
limit the configurable default stack/guard size for threads
limit to 8MB/1MB, repectively. since the defaults cannot be reduced once increased, excessively large settings would lead to an unrecoverably broken state. this change is in preparation to allow defaults to be increased via program headers at the linker level. creation of threads that really need larger sizes needs to be done with an explicit attribute.
-rw-r--r--src/internal/pthread_impl.h7
-rw-r--r--src/thread/default_attr.c4
-rw-r--r--src/thread/pthread_setattr_default_np.c12
3 files changed, 15 insertions, 8 deletions
diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h
index 26e6e1df..e73a251f 100644
--- a/src/internal/pthread_impl.h
+++ b/src/internal/pthread_impl.h
@@ -182,12 +182,15 @@ hidden void __acquire_ptc(void);
hidden void __release_ptc(void);
hidden void __inhibit_ptc(void);
-extern hidden size_t __default_stacksize;
-extern hidden size_t __default_guardsize;
+extern hidden unsigned __default_stacksize;
+extern hidden unsigned __default_guardsize;
#define DEFAULT_STACK_SIZE 81920
#define DEFAULT_GUARD_SIZE 4096
+#define DEFAULT_STACK_MAX (8<<20)
+#define DEFAULT_GUARD_MAX (1<<20)
+
#define __ATTRP_C11_THREAD ((void*)(uintptr_t)-1)
#endif
diff --git a/src/thread/default_attr.c b/src/thread/default_attr.c
index 46fe98ee..dce96409 100644
--- a/src/thread/default_attr.c
+++ b/src/thread/default_attr.c
@@ -1,4 +1,4 @@
#include "pthread_impl.h"
-size_t __default_stacksize = DEFAULT_STACK_SIZE;
-size_t __default_guardsize = DEFAULT_GUARD_SIZE;
+unsigned __default_stacksize = DEFAULT_STACK_SIZE;
+unsigned __default_guardsize = DEFAULT_GUARD_SIZE;
diff --git a/src/thread/pthread_setattr_default_np.c b/src/thread/pthread_setattr_default_np.c
index 256f0685..58486220 100644
--- a/src/thread/pthread_setattr_default_np.c
+++ b/src/thread/pthread_setattr_default_np.c
@@ -2,6 +2,9 @@
#include "pthread_impl.h"
#include <string.h>
+#define MIN(a,b) ((a)<(b) ? (a) : (b))
+#define MAX(a,b) ((a)>(b) ? (a) : (b))
+
int pthread_setattr_default_np(const pthread_attr_t *attrp)
{
/* Reject anything in the attr object other than stack/guard size. */
@@ -11,11 +14,12 @@ int pthread_setattr_default_np(const pthread_attr_t *attrp)
if (memcmp(&tmp, &zero, sizeof tmp))
return EINVAL;
+ unsigned stack = MIN(attrp->_a_stacksize, DEFAULT_STACK_MAX);
+ unsigned guard = MIN(attrp->_a_guardsize, DEFAULT_GUARD_MAX);
+
__inhibit_ptc();
- if (attrp->_a_stacksize >= __default_stacksize)
- __default_stacksize = attrp->_a_stacksize;
- if (attrp->_a_guardsize >= __default_guardsize)
- __default_guardsize = attrp->_a_guardsize;
+ __default_stacksize = MAX(__default_stacksize, stack);
+ __default_guardsize = MAX(__default_guardsize, guard);
__release_ptc();
return 0;