From f25238ffe0455013174438376b3ee88df496f9d1 Mon Sep 17 00:00:00 2001 From: Maxim Ostapenko Date: Mon, 10 Aug 2015 10:47:54 +0300 Subject: 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. --- elf/tst-nodelete2.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 elf/tst-nodelete2.c (limited to 'elf/tst-nodelete2.c') diff --git a/elf/tst-nodelete2.c b/elf/tst-nodelete2.c new file mode 100644 index 0000000000..388e8afb32 --- /dev/null +++ b/elf/tst-nodelete2.c @@ -0,0 +1,37 @@ +#include "../dlfcn/dlfcn.h" +#include +#include +#include + +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" -- cgit v1.2.1