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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 8BC61C43603 for ; Fri, 5 Mar 2021 12:25:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 65C306501D for ; Fri, 5 Mar 2021 12:25:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230420AbhCEMYw (ORCPT ); Fri, 5 Mar 2021 07:24:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:59154 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230409AbhCEMYY (ORCPT ); Fri, 5 Mar 2021 07:24:24 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id D3C4665023; Fri, 5 Mar 2021 12:24:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614947064; bh=GM+0cx1RspxAZTGMRF4bmBrImrhA1SdxQTfGeOTsh7c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=y6IUzLGlHf9RlgGLroovLtTaMRFoCu8OK9f87K7ABZ0QsVEsU+Z0B9jGrGKqCyvWo /RrBuhKAfpGvr+3HppaUd3pxgKrkCdlxljZGMF//Yt4oLQ3iYzQtqzKv8uXBTkwt+d Ij1c3EPjArzFINmGwfs3rE4zJkri6KalLrNkSLlc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+cb3b69ae80afd6535b0e@syzkaller.appspotmail.com, Peter Zijlstra , "Paul E. McKenney" Subject: [PATCH 5.11 005/104] sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled Date: Fri, 5 Mar 2021 13:20:10 +0100 Message-Id: <20210305120903.441413880@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210305120903.166929741@linuxfoundation.org> References: <20210305120903.166929741@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra commit 1b7af295541d75535374325fd617944534853919 upstream. The try_invoke_on_locked_down_task() function currently requires that interrupts be enabled, but it is called with interrupts disabled from rcu_print_task_stall(), resulting in an "IRQs not enabled as expected" diagnostic. This commit therefore updates try_invoke_on_locked_down_task() to use raw_spin_lock_irqsave() instead of raw_spin_lock_irq(), thus allowing use from either context. Link: https://lore.kernel.org/lkml/000000000000903d5805ab908fc4@google.com/ Link: https://lore.kernel.org/lkml/20200928075729.GC2611@hirez.programming.kicks-ass.net/ Reported-by: syzbot+cb3b69ae80afd6535b0e@syzkaller.appspotmail.com Signed-off-by: Peter Zijlstra Signed-off-by: Paul E. McKenney Signed-off-by: Greg Kroah-Hartman --- kernel/sched/core.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3478,7 +3478,7 @@ out: /** * try_invoke_on_locked_down_task - Invoke a function on task in fixed state - * @p: Process for which the function is to be invoked. + * @p: Process for which the function is to be invoked, can be @current. * @func: Function to invoke. * @arg: Argument to function. * @@ -3496,12 +3496,11 @@ out: */ bool try_invoke_on_locked_down_task(struct task_struct *p, bool (*func)(struct task_struct *t, void *arg), void *arg) { - bool ret = false; struct rq_flags rf; + bool ret = false; struct rq *rq; - lockdep_assert_irqs_enabled(); - raw_spin_lock_irq(&p->pi_lock); + raw_spin_lock_irqsave(&p->pi_lock, rf.flags); if (p->on_rq) { rq = __task_rq_lock(p, &rf); if (task_rq(p) == rq) @@ -3518,7 +3517,7 @@ bool try_invoke_on_locked_down_task(stru ret = func(p, arg); } } - raw_spin_unlock_irq(&p->pi_lock); + raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags); return ret; }