[Bug 239475] Linking libthr with -nodefaultlibs statically can cause infinite recursion
bugzilla-noreply at freebsd.org
bugzilla-noreply at freebsd.org
Sat Jul 27 14:22:17 UTC 2019
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=239475
Konstantin Belousov <kib at FreeBSD.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |kib at FreeBSD.org
--- Comment #1 from Konstantin Belousov <kib at FreeBSD.org> ---
For me it was reproduced as infinite loop, perhaps due to the the tail call
elimination. The issue is that when -lc is passed first,
__pthread_cleanup_push_imp is found in libc, and then the libthr jump table,
which references the symbol, is satisfied with the same libc definition.
Try this, I did not even compiled with the patch. It might require some
additional tweaking to get the stuff actually working.
diff --git a/lib/libthr/thread/thr_clean.c b/lib/libthr/thread/thr_clean.c
index 5a93d94a7e5..7bc7d62b617 100644
--- a/lib/libthr/thread/thr_clean.c
+++ b/lib/libthr/thread/thr_clean.c
@@ -49,6 +49,10 @@ __FBSDID("$FreeBSD$");
__weak_reference(_pthread_cleanup_push, pthread_cleanup_push);
__weak_reference(_pthread_cleanup_pop, pthread_cleanup_pop);
+/* help static linking when libc symbols have preference */
+__weak_reference(__pthread_cleanup_push_imp, __pthread_cleanup_push_imp1);
+__weak_reference(__pthread_cleanup_pop_imp, pthread_cleanup_pop_imp1);
+
void
__pthread_cleanup_push_imp(void (*routine)(void *), void *arg,
struct _pthread_cleanup_info *info)
diff --git a/lib/libthr/thread/thr_init.c b/lib/libthr/thread/thr_init.c
index 7b043a38b1f..22802c0ae1a 100644
--- a/lib/libthr/thread/thr_init.c
+++ b/lib/libthr/thread/thr_init.c
@@ -202,6 +202,10 @@ STATIC_LIB_REQUIRE(_thread_state_running);
#define DUAL_ENTRY(entry) \
(pthread_func_t)entry, (pthread_func_t)entry
+void __pthread_cleanup_push_imp1(void (*)(void *), void *,
+ struct _pthread_cleanup_info *);
+void __pthread_cleanup_pop_imp1(int);
+
static pthread_func_t jmp_table[][2] = {
{DUAL_ENTRY(_pthread_atfork)}, /* PJT_ATFORK */
{DUAL_ENTRY(_pthread_attr_destroy)}, /* PJT_ATTR_DESTROY */
@@ -265,8 +269,8 @@ static pthread_func_t jmp_table[][2] = {
{DUAL_ENTRY(_pthread_setspecific)}, /* PJT_SETSPECIFIC */
{DUAL_ENTRY(_pthread_sigmask)}, /* PJT_SIGMASK */
{DUAL_ENTRY(_pthread_testcancel)}, /* PJT_TESTCANCEL */
- {DUAL_ENTRY(__pthread_cleanup_pop_imp)},/* PJT_CLEANUP_POP_IMP */
- {DUAL_ENTRY(__pthread_cleanup_push_imp)},/* PJT_CLEANUP_PUSH_IMP */
+ {DUAL_ENTRY(__pthread_cleanup_pop_imp1)},/* PJT_CLEANUP_POP_IMP */
+ {DUAL_ENTRY(__pthread_cleanup_push_imp1)},/* PJT_CLEANUP_PUSH_IMP */
{DUAL_ENTRY(_pthread_cancel_enter)}, /* PJT_CANCEL_ENTER */
{DUAL_ENTRY(_pthread_cancel_leave)}, /* PJT_CANCEL_LEAVE */
{DUAL_ENTRY(_pthread_mutex_consistent)},/* PJT_MUTEX_CONSISTENT */
--
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