glibc

Tree: 352db0bd05

Author	SHA1	Message	Date
Joseph Myers	f7a9f785e5	Update copyright dates with scripts/update-copyrights.	10 years ago
Florian Weimer	f586e13286	Harden tls_dtor_list with pointer mangling [BZ #19018 ]	11 years ago
Siddhesh Poyarekar	a81a00ff94	Mention dl_load_lock by name in the comments Mention dl_load_lock by name instead of just 'load lock' in the comments. This makes it unambigious which lock we're talking about.	11 years ago
Siddhesh Poyarekar	90b37cac8b	Also use l_tls_dtor_count to decide on object unload (BZ #18657 ) When an TLS destructor is registered, we set the DF_1_NODELETE flag to signal that the object should not be destroyed. We then clear the DF_1_NODELETE flag when all destructors are called, which is wrong - the flag could have been set by other means too. This patch replaces this use of the flag by using l_tls_dtor_count directly to determine whether it is safe to unload the object. This change has the added advantage of eliminating the lock taking when calling the destructors, which could result in a deadlock. The patch also fixes the test case tst-tls-atexit - it was making an invalid dlclose call, which would just return an error silently. I have also added a detailed note on concurrency which also aims to justify why I chose the semantics I chose for accesses to l_tls_dtor_count. Thanks to Torvald for his help in getting me started on this and (literally) teaching my how to approach the problem. Change verified on x86_64; the test suite does not show any regressions due to the patch. ChangeLog: [BZ #18657] * elf/dl-close.c (_dl_close_worker): Don't unload DSO if there are pending TLS destructor calls. * include/link.h (struct link_map): Add concurrency note for L_TLS_DTOR_COUNT. * stdlib/cxa_thread_atexit_impl.c (__cxa_thread_atexit_impl): Don't touch the link map flag. Atomically increment l_tls_dtor_count. (__call_tls_dtors): Atomically decrement l_tls_dtor_count. Avoid taking the load lock and don't touch the link map flag. * stdlib/tst-tls-atexit-nodelete.c: New test case. * stdlib/Makefile (tests): Use it. * stdlib/tst-tls-atexit.c (do_test): dlopen tst-tls-atexit-lib.so again before dlclose. Add conditionals to allow tst-tls-atexit-nodelete test case to use it.	11 years ago
Siddhesh Poyarekar	9ceb5f6251	Whitespace fixup in cxa_thread_atexit_impl.c	11 years ago
Joseph Myers	b168057aaa	Update copyright dates with scripts/update-copyrights.	11 years ago
Ondřej Bílka	a1ffb40e32	Use glibc_likely instead __builtin_expect.	12 years ago
Allan McRae	d4697bc93d	Update copyright notices with scripts/update-copyrights	12 years ago
Roland McGrath	e57b0c6100	Avoid unconditional __call_tls_dtors calls in static linking.	13 years ago
Siddhesh Poyarekar	2016b3cd19	Fix copyright year in new files	13 years ago
Siddhesh Poyarekar	ba384f6ed9	C++11 thread_local destructors support This feature is specifically for the C++ compiler to offload calling thread_local object destructors on thread program exit, to glibc. This is to overcome the possible complication of destructors of thread_local objects getting called after the DSO in which they're defined is unloaded by the dynamic linker. The DSO is marked as 'unloadable' if it has a constructed thread_local object and marked as 'unloadable' again when all the constructed thread_local objects defined in it are destroyed.	13 years ago

11 Commits (352db0bd059df1ad2da5d22e6ea3fd3e4f2ce236)