nptl/allocatestack.c: Fix stack mprotect alignment for STACK_GROWS_UP

mprotect() expects the first argument to be aligned to a page boundary.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

diff --git a/libpthread/nptl/allocatestack.c b/libpthread/nptl/allocatestack.c
index 9399c2a..3f0586d 100644 (file)
--- a/libpthread/nptl/allocatestack.c
+++ b/libpthread/nptl/allocatestack.c
@@ -645,7 +645,7 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp,
                        prot) != 0)
            goto mprot_error;
 #elif defined _STACK_GROWS_UP
-         if (mprotect ((char *) pd - pd->guardsize,
+         if (mprotect ((char *) (((uintptr_t) pd - pd->guardsize) & ~pagesize_m1),
                        pd->guardsize - guardsize, prot) != 0)
            goto mprot_error;
 #endif