Revert fix to tst-pthread-getattr since it fails on sparc

2 files changed, 16 insertions, 40 deletions

diff --git a/nptl/ChangeLog b/nptl/ChangeLog
index 0a1c10fb8a..71f8e954d5 100644
--- a/nptl/ChangeLog
+++ b/nptl/ChangeLog
@@ -1,3 +1,7 @@
+2012-07-25  Siddhesh Poyarekar  <siddhesh@redhat.com>
+
+	* tst-pthread-getattr.c: Revert last change.
+
 2012-07-20  Siddhesh Poyarekar  <siddhesh@redhat.com>
 
 	* tst-pthread-getattr.c (MAX_STACK_SIZE): New max cap for stack
diff --git a/nptl/tst-pthread-getattr.c b/nptl/tst-pthread-getattr.c
index 692bce4629..6f2cfc6514 100644
--- a/nptl/tst-pthread-getattr.c
+++ b/nptl/tst-pthread-getattr.c
@@ -23,38 +23,16 @@
 #include <sys/resource.h>
 #include <pthread.h>
 #include <alloca.h>
-#include <assert.h>
-
-/* There is an obscure bug in the kernel due to which RLIMIT_STACK is sometimes
-   returned as unlimited when it is not, which may cause this test to fail.
-   There is also the other case where RLIMIT_STACK is intentionally set as
-   unlimited or very high, which may result in a vma that is too large and again
-   results in a test case failure.  To avoid these problems, we cap the stack
-   size to one less than 8M.  See the following mailing list threads for more
-   information about this problem:
-   <http://sourceware.org/ml/libc-alpha/2012-06/msg00599.html>
-   <http://sourceware.org/ml/libc-alpha/2012-06/msg00713.html>.  */
-#define MAX_STACK_SIZE (8192 * 1024 - 1)
-
-#define _MIN(l,o) ((l) < (o) ? (l) : (o))
 
 /* Move the stack pointer so that stackaddr is accessible and then check if it
    really is accessible.  This will segfault if it fails.  */
-static void *
+static void
 allocate_and_test (void *stackaddr)
 {
   void *mem = &mem;
-  /* FIXME:  mem >= stackaddr for _STACK_GROWSUP.  */
+  /* FIXME:  The difference will be negative for _STACK_GROWSUP.  */
   mem = alloca ((size_t) (mem - stackaddr));
-  assert (mem <= stackaddr);
-
-  /* We don't access mem here because the compiler may move the stack pointer
-     beyond what we expect, thus making our alloca send the stack pointer
-     beyond stackaddr.  Using only stackaddr without the assert may make the
-     compiler think that this instruction is independent of the above alloca
-     and hence reshuffle to do this dereference before the alloca.  */
-  *(int *)stackaddr = 42;
-  return stackaddr;
+  *(int *)(mem) = 0;
 }
 
 static int
@@ -99,20 +77,17 @@ check_stack_top (void)
       return 1;
     }
 
-  printf ("current rlimit_stack is %zu\n", stack_limit.rlim_cur);
-
   if (get_self_pthread_attr ("check_stack_top", &stackaddr, &stacksize))
     return 1;
 
-  /* Reduce the rlimit to a page less that what is currently being returned
-     (subject to a maximum of MAX_STACK_SIZE) so that we ensure that
-     pthread_getattr_np uses rlimit.  The figure is intentionally unaligned so
-     to verify that pthread_getattr_np returns an aligned stacksize that
-     correctly fits into the rlimit.  We don't bother about the case where the
-     stack is limited by the vma below it and not by the rlimit because the
-     stacksize returned in that case is computed from the end of that vma and is
-     hence safe.  */
-  stack_limit.rlim_cur = _MIN(stacksize - 4095, MAX_STACK_SIZE);
+  /* Reduce the rlimit to a page less that what is currently being returned so
+     that we ensure that pthread_getattr_np uses rlimit.  The figure is
+     intentionally unaligned so to verify that pthread_getattr_np returns an
+     aligned stacksize that correctly fits into the rlimit.  We don't bother
+     about the case where the stack is limited by the vma below it and not by
+     the rlimit because the stacksize returned in that case is computed from
+     the end of that vma and is hence safe.  */
+  stack_limit.rlim_cur = stacksize - 4095;
   printf ("Adjusting RLIMIT_STACK to %zu\n", stack_limit.rlim_cur);
   if ((ret = setrlimit (RLIMIT_STACK, &stack_limit)))
     {
@@ -125,10 +100,7 @@ check_stack_top (void)
 
   printf ("Adjusted rlimit: stacksize=%zu, stackaddr=%p\n", stacksize,
           stackaddr);
-
-  /* So that the compiler does not optimize out this call.  */
-  stackaddr = allocate_and_test (stackaddr);
-  assert (*(int *)stackaddr == 42);
+  allocate_and_test (stackaddr);
 
   puts ("Stack top tests done");