commit 8f85075a2e9c26ff7486d4bbaf358999807d215c

Author: Szabolcs Nagy <szabolcs.nagy@arm.com>

Date:   Thu Dec 31 12:24:38 2020 +0000

    elf: Add a DTV setup test [BZ #27136]

    The test dlopens a large number of modules with TLS, they are reused

    from an existing test.

    The test relies on the reuse of slotinfo entries after dlclose, without

    bug 27135 fixed this needs a failing dlopen. With a slotinfo list that

    has non-monotone increasing generation counters, bug 27136 can trigger.

    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

Conflicts:

	elf/Makefile

	  (usual test differences)

diff --git a/elf/Makefile b/elf/Makefile

index 82fb019a634caf81..0995d810b57d0dda 100644

--- a/elf/Makefile

+++ b/elf/Makefile

@@ -209,7 +209,8 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \

 	 tst-audit14 tst-audit15 tst-audit16 \

 	 tst-tls-ie tst-tls-ie-dlmopen \

 	 argv0test \

-	 tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask

+	 tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask \

+	 tst-tls20

 #	 reldep9

 tests-internal += loadtest unload unload2 circleload1 \

 	 neededtest neededtest2 neededtest3 neededtest4 \

@@ -332,6 +333,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \

 		libmarkermod2-1 libmarkermod2-2 \

 		libmarkermod3-1 libmarkermod3-2 libmarkermod3-3 \

 		libmarkermod4-1 libmarkermod4-2 libmarkermod4-3 libmarkermod4-4 \

+		tst-tls20mod-bad

 # Most modules build with _ISOMAC defined, but those filtered out

 # depend on internal headers.

@@ -1828,3 +1830,9 @@ $(objpfx)tst-rtld-help.out: $(objpfx)ld.so

 	fi; \

 	(exit $$status); \

 	$(evaluate-test)

+

+# Reuses tst-tls-many-dynamic-modules

+tst-tls20mod-bad.so-no-z-defs = yes

+$(objpfx)tst-tls20: $(libdl) $(shared-thread-library)

+$(objpfx)tst-tls20.out: $(objpfx)tst-tls20mod-bad.so \

+			$(tst-tls-many-dynamic-modules:%=$(objpfx)%.so)

diff --git a/elf/tst-tls20.c b/elf/tst-tls20.c

new file mode 100644

index 0000000000000000..ac5f8c8d39b66dd6

--- /dev/null

+++ b/elf/tst-tls20.c

@@ -0,0 +1,98 @@

+/* Test dtv setup if entries don't have monotone increasing generation.

+   Copyright (C) 2021 Free Software Foundation, Inc.

+   This file is part of the GNU C Library.

+

+   The GNU C Library is free software; you can redistribute it and/or

+   modify it under the terms of the GNU Lesser General Public

+   License as published by the Free Software Foundation; either

+   version 2.1 of the License, or (at your option) any later version.

+

+   The GNU C Library is distributed in the hope that it will be useful,

+   but WITHOUT ANY WARRANTY; without even the implied warranty of

+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

+   Lesser General Public License for more details.

+

+   You should have received a copy of the GNU Lesser General Public

+   License along with the GNU C Library; if not, see

+   <http://www.gnu.org/licenses/>.  */

+

+#include <dlfcn.h>

+#include <pthread.h>

+#include <stdio.h>

+#include <stdlib.h>

+#include <support/check.h>

+#include <support/xdlfcn.h>

+#include <support/xthread.h>

+

+#define NMOD 100

+static void *mod[NMOD];

+

+static void

+load_fail (void)

+{

+  /* Expected to fail because of a missing symbol.  */

+  void *m = dlopen ("tst-tls20mod-bad.so", RTLD_NOW);

+  if (m != NULL)

+    FAIL_EXIT1 ("dlopen of tst-tls20mod-bad.so succeeded\n");

+}

+

+static void

+load_mod (int i)

+{

+  char *buf = xasprintf ("tst-tls-manydynamic%02dmod.so", i);

+  mod[i] = xdlopen (buf, RTLD_LAZY);

+  free (buf);

+}

+

+static void

+unload_mod (int i)

+{

+  if (mod[i] != NULL)

+    xdlclose (mod[i]);

+  mod[i] = NULL;

+}

+

+static void

+access (int i)

+{

+  char *buf = xasprintf ("tls_global_%02d", i);

+  dlerror ();

+  int *p = dlsym (mod[i], buf);

+  printf ("mod[%d]: &tls = %p\n", i, p);

+  if (p == NULL)

+    FAIL_EXIT1 ("dlsym failed: %s\n", dlerror ());

+  ++*p;

+  free (buf);

+}

+

+static void *

+start (void *a)

+{

+  for (int i = 0; i < NMOD; i++)

+    if (mod[i] != NULL)

+      access (i);

+  return 0;

+}

+

+static int

+do_test (void)

+{

+  int i;

+

+  for (i = 0; i < NMOD; i++)

+    {

+      load_mod (i);

+      /* Bump the generation of mod[0] without using new dtv slot.  */

+      unload_mod (0);

+      load_fail (); /* Ensure GL(dl_tls_dtv_gaps) is true: see bug 27135.  */

+      load_mod (0);

+      /* Access TLS in all loaded modules.  */

+      pthread_t t = xpthread_create (0, start, 0);

+      xpthread_join (t);

+    }

+  for (i = 0; i < NMOD; i++)

+    unload_mod (i);

+  return 0;

+}

+

+#include <support/test-driver.c>

diff --git a/elf/tst-tls20mod-bad.c b/elf/tst-tls20mod-bad.c

new file mode 100644

index 0000000000000000..c1aed8ea7deffd22

--- /dev/null

+++ b/elf/tst-tls20mod-bad.c

@@ -0,0 +1,2 @@

+void missing_symbol (void);

+void f (void) {missing_symbol ();}