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>
This commit is contained in:
Szabolcs Nagy 2020-12-31 12:24:38 +00:00
parent d2b997c717
commit 8f85075a2e
3 changed files with 109 additions and 1 deletions

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@ -222,7 +222,8 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
tst-audit14 tst-audit15 tst-audit16 \
tst-single_threaded tst-single_threaded-pthread \
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 \
@ -344,6 +345,7 @@ 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.
@ -1922,3 +1924,9 @@ $(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)

98
elf/tst-tls20.c Normal file
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@ -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>

2
elf/tst-tls20mod-bad.c Normal file
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@ -0,0 +1,2 @@
void missing_symbol (void);
void f (void) {missing_symbol ();}