From d146da5d08d432b455d717e03d9130be166b8edb Mon Sep 17 00:00:00 2001 From: Mark Johnston Date: Fri, 2 Feb 2024 09:23:53 -0500 Subject: [PATCH] libthr: Force the thr_wake() symbol to be resolved during initialization Otherwise the lock upgrade performed by rtld's load_filtees() can result in infinite recursion, wherein: 1. _rtld_bind() acquires the bind read lock, 2. the source DSO's filtees haven't been loaded yet, so the lock upgrade in load_filtees() cause rtld to jump to _rtld_bind() and release the bind lock, 3. _thr_rtld_lock_release() calls _thr_ast(), which calls thr_wake(), which hasn't been resolved yet, 4. _rtld_bind() acquires the bind read lock in order to resolve thr_wake(), 5. ... See the linked pull request for an instance of this problem arising with libsys. That particular instance is also worked around by commit e7951d0b04e6. Reported by: brooks Reviewed by: kib Pull Request: https://github.com/freebsd/freebsd-src/pull/908 MFC after: 1 week Sponsored by: Innovate UK (cherry picked from commit 36f0a34ca645d49ec79d60ea7e773374ef0991ea) --- lib/libthr/thread/thr_rtld.c | 1 + 1 file changed, 1 insertion(+) diff --git a/lib/libthr/thread/thr_rtld.c b/lib/libthr/thread/thr_rtld.c index 9026abf941e..767b4735e1f 100644 --- a/lib/libthr/thread/thr_rtld.c +++ b/lib/libthr/thread/thr_rtld.c @@ -238,6 +238,7 @@ _thr_rtld_init(void) mprotect(NULL, 0, 0); _rtld_get_stack_prot(); + thr_wake(-1); li.rtli_version = RTLI_VERSION; li.lock_create = _thr_rtld_lock_create;