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=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 41B58C2D0DB for ; Thu, 23 Jan 2020 14:53:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 157C321835 for ; Thu, 23 Jan 2020 14:53:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="VFUCclZb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728665AbgAWOx4 (ORCPT ); Thu, 23 Jan 2020 09:53:56 -0500 Received: from mail-pf1-f194.google.com ([209.85.210.194]:36244 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728792AbgAWOx4 (ORCPT ); Thu, 23 Jan 2020 09:53:56 -0500 Received: by mail-pf1-f194.google.com with SMTP id w2so1662161pfd.3; Thu, 23 Jan 2020 06:53:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=gx1EwHhSeFAygAuuMCDt/vxczuYsXqL8AapATfNX7y8=; b=VFUCclZbsvs3ZYUE86h0BVB6542Nh/HbW0yALhQI9boAo07OpF99xuKWuhlGDBTVxq mX7S38mG1dVdVZ4scl37EJFo06E1JlA+w5S67OIBhcOcj99mA6/WXvnaA7qwLOomD7zX LxP/fa1TGRCaYGqYGXZTFJhaXd0YPTXYIhH2ycGMovnVFf5lZrJlCknZ2tlvCAHh1mXD KySUmdepz5hkHoGY24P8TtSto5IsSsMlDPJmjnxcyFU89hMKaryDZMBMSzDYVZvcHpEZ Nu4WsFHqPSa7/i1MMK636JOHUwJFlvT1q5Pnf667EQcLC485+XsaNE/uIRLFGODYxMAy VeQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=gx1EwHhSeFAygAuuMCDt/vxczuYsXqL8AapATfNX7y8=; b=Y2eh+0QFTgEzQOgzA7sFSsvve4gL7+N8hLzZijYW5jIDQokNm27rFzX+DJr3C7cufV GsfUvF/9+Pkuq+awjDqb69L8gF7xhBnmOsDKlqQ0QLQ086hpZ0ChFTWCT2wCDQwtsZqB JhpHIgGX+P0UQZqD4sA8JbRO2ADcdf9wZS7uvbnjIlYa3KdCiLbsYAcpd4KJRSrNgLEa /rG9ui9Gy9TM/LsTuozwcxilQtGlrlhvPputGgVXo2KB0g+a2lVkVIUbIS+UUf+f7jZY wOvPMb/UwIi42jRv6O5/Aq73F6IbsHX2NUY9zX0xNCzYQnGzlZlgmGP4utLp0TEOKwiB l9Mg== X-Gm-Message-State: APjAAAV9rTXqg1pyiRApu4/bY/Tn9moEHNaZYOYJFapY7G+mlKL0PIc0 HIkH7AzlanrpjNJjXvd7ZQ== X-Google-Smtp-Source: APXvYqzuuPGh4gpKk33IILFsa7XJBoe6la2FVwOIjW02LC/QfoGe4XDCFdwUi/OzBda0oBPz4ggbWQ== X-Received: by 2002:a63:213:: with SMTP id 19mr4382178pgc.160.1579791236088; Thu, 23 Jan 2020 06:53:56 -0800 (PST) Received: from madhuparna-HP-Notebook.nitk.ac.in ([2402:3a80:1ee5:f6bd:65db:7abb:c28f:eeed]) by smtp.gmail.com with ESMTPSA id o184sm3206955pgo.62.2020.01.23.06.53.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Jan 2020 06:53:55 -0800 (PST) From: madhuparnabhowmik10@gmail.com To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, ebiederm@xmission.com, christian.brauner@ubuntu.com, oleg@redhat.com, paulmck@kernel.org Cc: joel@joelfernandes.org, linux-kernel@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org, frextrite@gmail.com, rcu@vger.kernel.org, Madhuparna Bhowmik Subject: [PATCH] sched.h: Annotate sighand_struct with __rcu Date: Thu, 23 Jan 2020 20:23:05 +0530 Message-Id: <20200123145305.10652-1-madhuparnabhowmik10@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Madhuparna Bhowmik This patch fixes the following sparse errors by annotating the sighand_struct with __rcu kernel/fork.c:1511:9: error: incompatible types in comparison expression kernel/exit.c:100:19: error: incompatible types in comparison expression kernel/signal.c:1370:27: error: incompatible types in comparison expression This fix introduces the following sparse error in signal.c due to checking the sighand pointer without rcu primitives: kernel/signal.c:1386:21: error: incompatible types in comparison expression This new sparse error is also addressed in this patch. Signed-off-by: Madhuparna Bhowmik --- include/linux/sched.h | 2 +- kernel/signal.c | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index b511e178a89f..7a351360ad54 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -918,7 +918,7 @@ struct task_struct { /* Signal handlers: */ struct signal_struct *signal; - struct sighand_struct *sighand; + struct sighand_struct __rcu *sighand; sigset_t blocked; sigset_t real_blocked; /* Restored if set_restore_sigmask() was used: */ diff --git a/kernel/signal.c b/kernel/signal.c index bcd46f547db3..1272def37462 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1383,7 +1383,8 @@ struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, * must see ->sighand == NULL. */ spin_lock_irqsave(&sighand->siglock, *flags); - if (likely(sighand == tsk->sighand)) + if (likely(sighand == rcu_dereference_protected(tsk->sighand, + lockdep_is_held(&sighand->siglock)))) break; spin_unlock_irqrestore(&sighand->siglock, *flags); } -- 2.17.1