From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1CE06C2F3D5 for ; Mon, 21 Jan 2019 17:05:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DB47A20989 for ; Mon, 21 Jan 2019 17:05:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726702AbfAURFQ (ORCPT ); Mon, 21 Jan 2019 12:05:16 -0500 Received: from mx1.redhat.com ([209.132.183.28]:58084 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725879AbfAURFP (ORCPT ); Mon, 21 Jan 2019 12:05:15 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4DE603D962; Mon, 21 Jan 2019 17:05:15 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.34.27.18]) by smtp.corp.redhat.com (Postfix) with SMTP id 3CE4360A9F; Mon, 21 Jan 2019 17:05:13 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Mon, 21 Jan 2019 18:05:14 +0100 (CET) Date: Mon, 21 Jan 2019 18:05:12 +0100 From: Oleg Nesterov To: Elena Reshetova Cc: mingo@redhat.com, peterz@infradead.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, keescook@chromium.org, tglx@linutronix.de Subject: Re: [PATCH 1/5] sched: convert sighand_struct.count to refcount_t Message-ID: <20190121170511.GA8088@redhat.com> References: <1547814450-18902-1-git-send-email-elena.reshetova@intel.com> <1547814450-18902-2-git-send-email-elena.reshetova@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1547814450-18902-2-git-send-email-elena.reshetova@intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Mon, 21 Jan 2019 17:05:15 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/18, Elena Reshetova wrote: > > --- a/fs/proc/task_nommu.c > +++ b/fs/proc/task_nommu.c > @@ -64,7 +64,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm) > else > bytes += kobjsize(current->files); > > - if (current->sighand && atomic_read(¤t->sighand->count) > 1) > + if (current->sighand && refcount_read(¤t->sighand->count) > 1) > sbytes += kobjsize(current->sighand); > else > bytes += kobjsize(current->sighand); I fail to understand this code with or without the patch... I do not see how is it possible to hit ->sighand == NULL or sighand->count == 0 in proc_pid_status() paths. Nevermind, this is off-topic. Reviewed-by: Oleg Nesterov