From nobody Thu Apr 17 01:05:56 2025 X-Original-To: dev-commits-src-all@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 4ZdKTK3W9Xz5tVpc; Thu, 17 Apr 2025 01:05:57 +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 4ZdKTK0nshz3Y3M; Thu, 17 Apr 2025 01:05:57 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1744851957; 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=6byuubT4cSGwccPGW6jzvxifC+hpZA2CPpG2l/BKkz8=; b=lxalQjEqbCTft2aolPr0etFpqdkcRZmYll1N+yiRJOP6LSToOZRSeEHYrwfg8va7xsnI+D NmcjF9EZ2y7NhAJaIb1TLfNTt5cllKUVQoENqbT2w7FdQjugHfRqpd2hDfF8rBF35pcppy jiak6JsxOxGaxCfAcT8CMQjBZ8tNN19TkFaySbECvWSND5rX2Vlnw/L7V/dUp9U1Q0KQ/a /3vpFqGPcDAGYbHLuBb42BuM2ngLOvbvBPPmJobGll4mCQ0dH+3RdESGzg9kNb1EEYKhC3 Q7/KebjC8Ye4I09jWtEuIDP/Qj5a1dBLYqujlgj96KNuOrWOaT3u/43rniANjg== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1744851957; a=rsa-sha256; cv=none; b=KahVqpNyHLRUcU5EMJ8tw0fx2wjMUfflLjm8l7VYEaoE9rQC/Euh64DvcMRhUwbmT7Eml4 9+gAmTfNrhRVPbttQzqCaKhcO35YI0HzvUzzfyZKLnm6i0AvxPLafmRAdmbxm6Fgxgyc3z gaTo/87nBmxg50pgUa3nm/IF1J/o6U6AmlIQ1YTHMBSBBFP/wi3HT/P0VIM8PO3+gfjyVP WfqbJURRfyZnEZrak4F+ffHlpoP/sqnR6H7lspJVj3Ybphv0eu5TEBgbimVwnIE1Z8R3ew RMvyA3L4RgAHjGHH4Ok+Xvmn6UhJ4mvbsnk1xs0Moth9eNWcEwU8IE8STU5pDg== 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=1744851957; 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=6byuubT4cSGwccPGW6jzvxifC+hpZA2CPpG2l/BKkz8=; b=EywyWlf8osmlHc8Tzswo2yusfQ4dMYmAYY0w131xu1cxuXC0yi6psqeBRdvwCQ/LBRw5HW R5jZ6CzsNXK16Cj1Zt7SmpbkClt/x8LzL542sWxa3flJtzYLgL1lLd/TBBW8GKso0QqWgi a0TFnzDWHbHgn1kuuLqPtW0H/tc8EgmXhcEjx5XavNqG0sa3bc8lmX850esYLuuDBnZDKD OgGmOtwTGrczYLYIZofRU+po3MY6AyfARo9DUJJ3k4iaRJNJuzd9dinDmS8URV5hqlzwEK 1OVajyVr8Ak+qEBekgFNMxffMjrnP0V7fN5cf57IsWdPU+ZbdqeLXKy/P2Qmhw== 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 4ZdKTK04vjz9ps; Thu, 17 Apr 2025 01:05:57 +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 53H15uhh062446; Thu, 17 Apr 2025 01:05:56 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 53H15uHN062443; Thu, 17 Apr 2025 01:05:56 GMT (envelope-from git) Date: Thu, 17 Apr 2025 01:05:56 GMT Message-Id: <202504170105.53H15uHN062443@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: c43ae65b4b89 - stable/14 - libc: allow __cxa_atexit handlers to be added during __cxa_finalize List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-all@freebsd.org Sender: owner-dev-commits-src-all@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/14 X-Git-Reftype: branch X-Git-Commit: c43ae65b4b89be422cdcd399a7abc44f6db4b298 Auto-Submitted: auto-generated The branch stable/14 has been updated by kevans: URL: https://cgit.FreeBSD.org/src/commit/?id=c43ae65b4b89be422cdcd399a7abc44f6db4b298 commit c43ae65b4b89be422cdcd399a7abc44f6db4b298 Author: Aurélien Croc de Suray AuthorDate: 2025-04-05 00:47:53 +0000 Commit: Kyle Evans CommitDate: 2025-04-17 01:01:36 +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 b2c10ca4cca5..6468b9ff0a62 100644 --- a/lib/libc/stdlib/atexit.c +++ b/lib/libc/stdlib/atexit.c @@ -38,6 +38,7 @@ static char sccsid[] = "@(#)atexit.c 8.2 (Berkeley) 7/3/94"; #include "namespace.h" #include #include +#include #include #include #include @@ -59,6 +60,8 @@ _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) @@ -118,6 +121,9 @@ 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; } @@ -211,33 +217,38 @@ __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);