From nobody Thu Apr 17 02:23:21 2025 X-Original-To: dev-commits-src-branches@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4ZdMBd4XxHz5tbL6; Thu, 17 Apr 2025 02:23:21 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R10" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4ZdMBd2sKlz3gkN; Thu, 17 Apr 2025 02:23:21 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1744856601; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=24X13bY3+ymZbk2L3zz745vvhcns1CkqvatKzS4x2QU=; b=ODvhW/fdTg5IZBJCw3gi8TkFctPKESsV1jvKVf68gYldYfXRhnMl3RkHIM3fFQWYsnokNz QT+AbT6oG8EA+hJQYZYRfZmx7DQqQ9Qgz1Uja/xFLSs7F69tIRVOk5QWqu0y+vRJKenudl zin5T4jdYM/Hw5STVS5lYVBRLouxMYKOihANUpJ6cnlJ8kgu1GOzVMNuXW9mjQppNyL54x 6kUlcXJmahRL1f7RpLUXf7RX34DUB0LL9zZpVyxMaRnOe/1nU6CZD1MH1Gb8R8wCm6mV4u JKZL4VV+MvFzCNVAnLIxbOLYKF7O9tqBOzkBzFystXyqCjss9rlQr8ts5Q4z+w== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1744856601; a=rsa-sha256; cv=none; b=LxS/uRkaaPVJFt3vH+9t6J/PR0+Roevvqx4EqNXTq3b1gbYAO5DcSrEoPyF21DGWWodtAJ aioLVfkPSqtz+SHl47+axUhDPG0uJtzBeDA0Mnhye7iFdamwctrjqLWyTlI6OmegJxRIHe hXDdxlLfkNS429hUEjx8dNJid4Pn4CgdalxD0Gp6/4CzS4Yrwiyh+qWUPmBvKcNZqyTS6o Q3N8rHjEiqlFmsExdtOcb66yPk8mBRteJuWEmyNLptZ74UvT+s9smAMRdvzD/5XYUHVepp AG0NoR+CtLL5iAihXDytm05FDSZn+L7VnmWyEsItyu0nvlLy+8qju9QUzmlGww== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1744856601; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=24X13bY3+ymZbk2L3zz745vvhcns1CkqvatKzS4x2QU=; b=tw9cCX1nQJXuN63cYwQFu87T9YVhaElYCp3Q4zB1jQo+0PfIlhyRD4clb8Wd7ar2H6ticA 6S0LKBCLmFWep3iPvuGd8KZaigUjVoBI6N313MHt+7BJV5tqwu3p+NxFa+UesqMuoC+jfM gpI2lpbaYtZKRcHXu5sVgz1N1UFGBaEEO+GnUwr1R3lZLwOBxfAabrjft4seRBYTV9bIC0 lqZEXLpZfX3yWNKk9AYDYyZKYNv/lQ+r3s/FLatrjg+HkuJ8jjF5iteQgLSyhMJ3JDXFAS cHcAN6bpPR5mPG4FqzwUd7ZpRAzPha3OlsKGBRtdC3yL7Vvcz1ywhng7Crt7mw== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4ZdMBd2H43zDDV; Thu, 17 Apr 2025 02:23:21 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.18.1/8.18.1) with ESMTP id 53H2NL3l011183; Thu, 17 Apr 2025 02:23:21 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 53H2NLTe011180; Thu, 17 Apr 2025 02:23:21 GMT (envelope-from git) Date: Thu, 17 Apr 2025 02:23:21 GMT Message-Id: <202504170223.53H2NLTe011180@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Kyle Evans Subject: git: 04f7496f89e2 - stable/13 - libc: allow __cxa_atexit handlers to be added during __cxa_finalize List-Id: Commits to the stable branches of the FreeBSD src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-branches List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-branches@freebsd.org Sender: owner-dev-commits-src-branches@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: kevans X-Git-Repository: src X-Git-Refname: refs/heads/stable/13 X-Git-Reftype: branch X-Git-Commit: 04f7496f89e28057079f3f0b1a02d7d9d874487f Auto-Submitted: auto-generated The branch stable/13 has been updated by kevans: URL: https://cgit.FreeBSD.org/src/commit/?id=04f7496f89e28057079f3f0b1a02d7d9d874487f commit 04f7496f89e28057079f3f0b1a02d7d9d874487f Author: Aurélien Croc de Suray AuthorDate: 2025-04-05 00:47:53 +0000 Commit: Kyle Evans CommitDate: 2025-04-17 01:02:12 +0000 libc: allow __cxa_atexit handlers to be added during __cxa_finalize science/dlib-cpp reveals an interesting scenario that works fine on other platforms but not on FreeBSD; notably, it ends up creating a new global object from some destructor which is called during __cxa_finalize. This breaks when libdlib is dlopen()ed and then subsequently dlclose()ed, as we never end up invoking the created object's dtor until program exit when the shlib is already unmapped. Fix it by noting when we're in the middle of __cxa_finalize for a dso, and then restarting the search if __cxa_atexit() was called in the middle somewhere. We wait until we've processed the initial set before starting over and processing the newly added handlers as if it were a complete set of handlers added during runtime. The alternative is calling them as they're added to maintain a LIFO in terms of total ordering, but in theory a constructor could add another global object that also needs to be destroyed, and that object needs to be destroyed after the one that constructed it to avoid creating unexpected lifetime issues. This manifests in the pdlib PHP extension for dlib crashing, see [0]. [0] https://github.com/goodspb/pdlib/issues/39 PR: 285870 Reviewed by: kevans (also supplied commit message) (cherry picked from commit 23427c8e1fedb9fc68ad0bd27a59c7ffd2b3008c) --- lib/libc/stdlib/atexit.c | 61 ++++++++++++++++++++++++++++-------------------- 1 file changed, 36 insertions(+), 25 deletions(-) diff --git a/lib/libc/stdlib/atexit.c b/lib/libc/stdlib/atexit.c index 6b63d9e728c4..5b39552821ed 100644 --- a/lib/libc/stdlib/atexit.c +++ b/lib/libc/stdlib/atexit.c @@ -39,6 +39,7 @@ static char sccsid[] = "@(#)atexit.c 8.2 (Berkeley) 7/3/94"; #include "namespace.h" #include #include +#include #include #include #include @@ -60,6 +61,8 @@ _Block_copy(void*); #define ATEXIT_FN_CXA 2 static pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER; +static void *current_finalize_dso = NULL; +static bool call_finalize_again = false; #define _MUTEX_LOCK(x) if (__isthreaded) _pthread_mutex_lock(x) #define _MUTEX_UNLOCK(x) if (__isthreaded) _pthread_mutex_unlock(x) @@ -119,6 +122,9 @@ atexit_register(struct atexit_fn *fptr) __atexit = p; } p->fns[p->ind++] = *fptr; + if (current_finalize_dso != NULL && + current_finalize_dso == fptr->fn_dso) + call_finalize_again = true; _MUTEX_UNLOCK(&atexit_mutex); return 0; } @@ -212,33 +218,38 @@ __cxa_finalize(void *dso) } _MUTEX_LOCK(&atexit_mutex); - for (p = __atexit; p; p = p->next) { - for (n = p->ind; --n >= 0;) { - if (p->fns[n].fn_type == ATEXIT_FN_EMPTY) - continue; /* already been called */ - fn = p->fns[n]; - if (dso != NULL && dso != fn.fn_dso) { - /* wrong DSO ? */ - if (!has_phdr || global_exit || - !__elf_phdr_match_addr(&phdr_info, - fn.fn_ptr.cxa_func)) - continue; + current_finalize_dso = dso; + do { + call_finalize_again = false; + for (p = __atexit; p; p = p->next) { + for (n = p->ind; --n >= 0;) { + if (p->fns[n].fn_type == ATEXIT_FN_EMPTY) + continue; /* already been called */ + fn = p->fns[n]; + if (dso != NULL && dso != fn.fn_dso) { + /* wrong DSO ? */ + if (!has_phdr || global_exit || + !__elf_phdr_match_addr(&phdr_info, + fn.fn_ptr.cxa_func)) + continue; + } + /* + Mark entry to indicate that this particular + handler has already been called. + */ + p->fns[n].fn_type = ATEXIT_FN_EMPTY; + _MUTEX_UNLOCK(&atexit_mutex); + + /* Call the function of correct type. */ + if (fn.fn_type == ATEXIT_FN_CXA) + fn.fn_ptr.cxa_func(fn.fn_arg); + else if (fn.fn_type == ATEXIT_FN_STD) + fn.fn_ptr.std_func(); + _MUTEX_LOCK(&atexit_mutex); } - /* - Mark entry to indicate that this particular handler - has already been called. - */ - p->fns[n].fn_type = ATEXIT_FN_EMPTY; - _MUTEX_UNLOCK(&atexit_mutex); - - /* Call the function of correct type. */ - if (fn.fn_type == ATEXIT_FN_CXA) - fn.fn_ptr.cxa_func(fn.fn_arg); - else if (fn.fn_type == ATEXIT_FN_STD) - fn.fn_ptr.std_func(); - _MUTEX_LOCK(&atexit_mutex); } - } + } while (call_finalize_again); + current_finalize_dso = NULL; _MUTEX_UNLOCK(&atexit_mutex); if (dso == NULL) _MUTEX_DESTROY(&atexit_mutex);