fix -fsanitize=thread findings

[Bruno Haible]

Applying CC="gcc -fsanitize=thread" to a gnulib testdir, I see
these findings:

test-get-rusage-as:
ERROR: ThreadSanitizer failed to allocate 0x12000 (73728) bytes of 
SignalContext (errno: 12)
ERROR: Failed to mmap

test-pthread-sigmask2:
WARNING: ThreadSanitizer: thread leak (pid=7460)

test-lock:
FATAL: ThreadSanitizer CHECK failed: 
../../../../src/libsanitizer/sanitizer_common/sanitizer_deadlock_detector.h:67 
"((n_all_locks_)) < 
(((sizeof(all_locks_with_contexts_)/sizeof((all_locks_with_contexts_)[0]))))" 
(0x40, 0x40)
    #0 <null> <null> (libtsan.so.0+0x000000075193)
    #1 <null> <null> (libtsan.so.0+0x00000007519b)
    #2 __sanitizer::CheckFailed(char const*, int, char const*, unsigned long 
long, unsigned long long) <null> (libtsan.so.0+0x000000079ce3)
    #3 <null> <null> (libtsan.so.0+0x00000007dacd)
    #4 <null> <null> (libtsan.so.0+0x000000071b95)
    #5 pthread_rwlock_wrlock <null> (libtsan.so.0+0x000000028e95)
    #6 test_once ../../gltests/test-lock.c:646 (test-lock+0x000000401dea)
    #7 main ../../gltests/test-lock.c:738 (test-lock+0x000000401dea)

test-getgroups:
eats up all available memory before being killed by the kernel.

This patch fixes the first two issues. The last two are beyond my control.


2019-03-09  Bruno Haible  <address@hidden>

        get-rusage-as, pthread_sigmask tests: Fix -fsanitize=thread findings.
        * lib/get-rusage-as.c (get_rusage_as): When compiled by
        "gcc -fsanitize=thread", don't try get_rusage_as_via_setrlimit.
        * tests/test-pthread_sigmask2.c (main): Clean up the killer_thread
        before exiting.

diff --git a/lib/get-rusage-as.c b/lib/get-rusage-as.c
index 73364c7..0762247 100644
--- a/lib/get-rusage-as.c
+++ b/lib/get-rusage-as.c
@@ -373,7 +373,7 @@ get_rusage_as_via_iterator (void)
 uintptr_t
 get_rusage_as (void)
 {
-#if (defined __APPLE__ && defined __MACH__) || defined _AIX || defined 
__CYGWIN__ || defined __MVS__ /* Mac OS X, AIX, Cygwin, z/OS */
+#if (defined __APPLE__ && defined __MACH__) || defined _AIX || defined 
__CYGWIN__ || defined __MVS__ || defined __SANITIZE_THREAD__ /* Mac OS X, AIX, 
Cygwin, z/OS, gcc -fsanitize=thread */
   /* get_rusage_as_via_setrlimit() does not work.
      Prefer get_rusage_as_via_iterator().  */
   return get_rusage_as_via_iterator ();
diff --git a/tests/test-pthread_sigmask2.c b/tests/test-pthread_sigmask2.c
index aa7ecf4..e02c312 100644
--- a/tests/test-pthread_sigmask2.c
+++ b/tests/test-pthread_sigmask2.c
@@ -84,6 +84,10 @@ main (int argc, char *argv[])
         before the call to pthread_sigmask() returns."  */
   ASSERT (sigint_occurred == 1);
 
+  /* Clean up the thread.  This avoid a "ThreadSanitizer: thread leak" warning
+     from "gcc -fsanitize=thread".  */
+  gl_thread_join (killer_thread, NULL);
+
   return 0;
 }