From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTP id B5B4A384607B for ; Thu, 24 Jun 2021 08:19:06 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org B5B4A384607B Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-570-sIAuSBj3PTuSYw8p_UMFOQ-1; Thu, 24 Jun 2021 04:19:04 -0400 X-MC-Unique: sIAuSBj3PTuSYw8p_UMFOQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2F6FF1054F93; Thu, 24 Jun 2021 08:19:03 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-112-228.ams2.redhat.com [10.36.112.228]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5465510190A7; Thu, 24 Jun 2021 08:19:02 +0000 (UTC) From: Florian Weimer To: Adhemerval Zanella via Libc-alpha Subject: Re: [PATCH v4 2/4] posix: Do not clobber errno by atfork handlers References: <20210623184354.395316-1-adhemerval.zanella@linaro.org> <20210623184354.395316-3-adhemerval.zanella@linaro.org> Date: Thu, 24 Jun 2021 10:19:00 +0200 In-Reply-To: <20210623184354.395316-3-adhemerval.zanella@linaro.org> (Adhemerval Zanella via Libc-alpha's message of "Wed, 23 Jun 2021 15:43:52 -0300") Message-ID: <877dijn097.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-12.7 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 Jun 2021 08:19:07 -0000 * Adhemerval Zanella via Libc-alpha: > Checked on x86_64-linux-gnu. > --- > posix/fork.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/posix/fork.c b/posix/fork.c > index 44caf8d166..9340511198 100644 > --- a/posix/fork.c > +++ b/posix/fork.c > @@ -103,6 +103,9 @@ __libc_fork (void) > } > else > { > + /* If _Fork failed, preserve its errno value. */ > + int save_errno = errno; > + > /* Release acquired locks in the multi-threaded case. */ > if (multiple_threads) > { > @@ -115,6 +118,8 @@ __libc_fork (void) > > /* Run the handlers registered for the parent. */ > __run_fork_handlers (atfork_run_parent, multiple_threads); > + > + __set_errno (save_errno); I think you should restrict the __set_errno call to pid < 0, so that errno is not 0 after a different value has been observed by the fork handlers. Thanks, Florian