From 42e09be9c23e730d42b331384d128dbba8719c04 Mon Sep 17 00:00:00 2001 From: kib Date: Mon, 8 Feb 2016 19:24:13 +0000 Subject: If libthr.so is dlopened without RTLD_GLOBAL flag, the libthr symbols do not participate in the global symbols namespace, but rtld locks are still replaced and functions are interposed. In particular, __pthread_map_stacks_exec is resolved to the libc version. If a library is loaded later, which requires adjustment of the stack protection mode, rtld calls into libc __pthread_map_stacks_exec due to the symbols scope. The libc version might recurse into binder and recursively acquire rtld bind lock, causing the hang. Make libc __pthread_map_stacks_exec() interposed, which synchronizes rtld locks and version of the stack exec hook when libthr loaded, regardless of the symbol scope control or symbol resolution order. The __pthread_map_stacks_exec() symbol is removed from the private version in libthr since libc symbol now operates correctly in presence of libthr. Reported and tested by: markj Sponsored by: The FreeBSD Foundation MFC after: 2 weeks --- lib/libc/sys/interposing_table.c | 1 + 1 file changed, 1 insertion(+) (limited to 'lib/libc/sys') diff --git a/lib/libc/sys/interposing_table.c b/lib/libc/sys/interposing_table.c index 08dfbb1..75bb280 100644 --- a/lib/libc/sys/interposing_table.c +++ b/lib/libc/sys/interposing_table.c @@ -78,6 +78,7 @@ interpos_func_t __libc_interposing[INTERPOS_MAX] = { SLOT(kevent, __sys_kevent), SLOT(wait6, __sys_wait6), SLOT(ppoll, __sys_ppoll), + SLOT(map_stacks_exec, __libc_map_stacks_exec), }; #undef SLOT -- cgit v1.1