glibc/elf/tst-nodelete2.c
Maxim Ostapenko f25238ffe0 Clear DF_1_NODELETE flag only for failed to load library.
https://sourceware.org/bugzilla/show_bug.cgi?id=18778

If dlopen fails to load an object that has triggered loading libpthread it
causes ld.so to unload libpthread because its DF_1_NODELETE flags has been
forcefully cleared. The next call to __rtdl_unlock_lock_recursive will crash
since pthread_mutex_unlock no longer exists.

This patch moves l->l_flags_1 &= ~DF_1_NODELETE out of loop through all loaded
libraries and performs the action only on inconsistent one.

	[BZ #18778]
	* elf/Makefile (tests): Add Add tst-nodelete2.
	(modules-names): Add tst-nodelete2mod.
	(tst-nodelete2mod.so-no-z-defs): New.
	($(objpfx)tst-nodelete2): Likewise.
	($(objpfx)tst-nodelete2.out): Likewise.
	(LDFLAGS-tst-nodelete2): Likewise.
	* elf/dl-close.c (_dl_close_worker): Move DF_1_NODELETE clearing
	out of loop through all loaded libraries.
	* elf/tst-nodelete2.c: New file.
	* elf/tst-nodelete2mod.c: Likewise.
2015-08-11 10:13:22 +02:00

38 lines
1.1 KiB
C

#include "../dlfcn/dlfcn.h"
#include <stdio.h>
#include <stdlib.h>
#include <gnu/lib-names.h>
static int
do_test (void)
{
int result = 0;
printf ("\nOpening pthread library.\n");
void *pthread = dlopen (LIBPTHREAD_SO, RTLD_LAZY);
/* This is a test for correct DF_1_NODELETE clearing when dlopen failure
happens. We should clear DF_1_NODELETE for failed library only, because
doing this for others (e.g. libpthread) might cause them to be unloaded,
that may lead to some global references (e.g. __rtld_lock_unlock) to be
broken. The dlopen should fail because of undefined symbols in shared
library, that cause DF_1_NODELETE to be cleared. For libpthread, this
flag should be set, because if not, SIGSEGV will happen in dlclose. */
if (dlopen ("tst-nodelete2mod.so", RTLD_NOW) != NULL)
{
printf ("Unique symbols test failed\n");
result = 1;
}
if (pthread)
dlclose (pthread);
if (result == 0)
printf ("SUCCESS\n");
return result;
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"