From patchwork Mon Oct 12 13:27:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 270228 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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 DA9C8C43457 for ; Mon, 12 Oct 2020 14:02:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9627220838 for ; Mon, 12 Oct 2020 14:02:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602511328; bh=tunlYpfNiwZtjEIQQxkuqN3PapJ/yxgpnKpkcb+AWAM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=j9+PX5nQyOaZATYa/2+qgXCBu3PyDlR04JxHRg/Fnb4QyVfCW2E84F3NNoqpLc1b5 FHUNxfVsAr73TwGzzP0B+bD7pDVDc2bmi0oXVM+jgCdGdhevqlkw68WZN9Jtsozfse 6XxF2MMr19Q0WKCIeo4Z4vIyL4j0bPhCxsW6HrQ0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390114AbgJLOCH (ORCPT ); Mon, 12 Oct 2020 10:02:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:40158 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730990AbgJLNiB (ORCPT ); Mon, 12 Oct 2020 09:38:01 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A139922246; Mon, 12 Oct 2020 13:37:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602509875; bh=tunlYpfNiwZtjEIQQxkuqN3PapJ/yxgpnKpkcb+AWAM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qTjZFfFrnyXx6iquN+RLLr4GZI1CtHvSBKFZGJyZYMC7LoqTXHzcoTuWCd310jF0t EQ3PZWVrdz8RbHH0FI28eVsI9EiQA8bdHTZupD1Q7fBjfgnIrJr/GyhntqWc2/aMaV ddjyTBOx8XpbsIkBkXMDW1hOWBQlh5yDVp8DiuEE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Srikar Dronamraju , Kajol Jain , "Peter Zijlstra (Intel)" , Ingo Molnar , Barret Rhoden , Sasha Levin Subject: [PATCH 4.14 67/70] perf: Fix task_function_call() error handling Date: Mon, 12 Oct 2020 15:27:23 +0200 Message-Id: <20201012132633.432960852@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201012132630.201442517@linuxfoundation.org> References: <20201012132630.201442517@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Kajol Jain [ Upstream commit 6d6b8b9f4fceab7266ca03d194f60ec72bd4b654 ] The error handling introduced by commit: 2ed6edd33a21 ("perf: Add cond_resched() to task_function_call()") looses any return value from smp_call_function_single() that is not {0, -EINVAL}. This is a problem because it will return -EXNIO when the target CPU is offline. Worse, in that case it'll turn into an infinite loop. Fixes: 2ed6edd33a21 ("perf: Add cond_resched() to task_function_call()") Reported-by: Srikar Dronamraju Signed-off-by: Kajol Jain Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Barret Rhoden Tested-by: Srikar Dronamraju Link: https://lkml.kernel.org/r/20200827064732.20860-1-kjain@linux.ibm.com Signed-off-by: Sasha Levin --- kernel/events/core.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index e50b140053f9a..5807fad2c4057 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -98,7 +98,7 @@ static void remote_function(void *data) * retry due to any failures in smp_call_function_single(), such as if the * task_cpu() goes offline concurrently. * - * returns @func return value or -ESRCH when the process isn't running + * returns @func return value or -ESRCH or -ENXIO when the process isn't running */ static int task_function_call(struct task_struct *p, remote_function_f func, void *info) @@ -114,7 +114,8 @@ task_function_call(struct task_struct *p, remote_function_f func, void *info) for (;;) { ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1); - ret = !ret ? data.ret : -EAGAIN; + if (!ret) + ret = data.ret; if (ret != -EAGAIN) break;