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 [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id EBC323858D3C for ; Thu, 26 Aug 2021 15:00:22 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org EBC323858D3C 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-419-25S67Gw3OYmgvlvLKn9Rkg-1; Thu, 26 Aug 2021 11:00:20 -0400 X-MC-Unique: 25S67Gw3OYmgvlvLKn9Rkg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DC6D3101C8A0; Thu, 26 Aug 2021 15:00:19 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.194.140]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0C4ED60C04; Thu, 26 Aug 2021 15:00:18 +0000 (UTC) From: Florian Weimer To: Adhemerval Zanella Cc: libc-alpha@sourceware.org Subject: Re: [PATCH v2 13/19] nptl: Use tidlock when accessing TID on pthread_getschedparam References: <20210823195047.543237-1-adhemerval.zanella@linaro.org> <20210823195047.543237-14-adhemerval.zanella@linaro.org> Date: Thu, 26 Aug 2021 17:00:17 +0200 In-Reply-To: <20210823195047.543237-14-adhemerval.zanella@linaro.org> (Adhemerval Zanella's message of "Mon, 23 Aug 2021 16:50:41 -0300") Message-ID: <874kbc5jzy.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 2.79 on 10.5.11.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-12.9 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_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) 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, 26 Aug 2021 15:00:24 -0000 * Adhemerval Zanella: > Checked on x86_64-linux-gnu. > --- > nptl/pthread_getschedparam.c | 16 +++++++++++++--- > 1 file changed, 13 insertions(+), 3 deletions(-) > > diff --git a/nptl/pthread_getschedparam.c b/nptl/pthread_getschedparam.c > index 94316cf897..c41d2a8341 100644 > --- a/nptl/pthread_getschedparam.c > +++ b/nptl/pthread_getschedparam.c > @@ -29,12 +29,18 @@ __pthread_getschedparam (pthread_t threadid, int *policy, > struct pthread *pd = (struct pthread *) threadid; > > /* Make sure the descriptor is valid. */ > - if (INVALID_TD_P (pd)) > - /* Not a valid thread handle. */ > - return ESRCH; > + sigset_t oldmask; > + __libc_signal_block_all (&oldmask); > + lll_lock (pd->tidlock, LLL_PRIVATE); > > int result = 0; > > + if (pd->tid == 0) > + { > + result = ESRCH; > + goto out; > + } We can avoid returning ESRCH by storing the parameters unconditionally in the TCB. That should also simplify the implementation, potentially at the cost of a few extra system calls. Thanks, Florian