From patchwork Tue Oct 27 13:51:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 312487 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 30380C8301B for ; Tue, 27 Oct 2020 15:47:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC1D92072C for ; Tue, 27 Oct 2020 15:47:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603813651; bh=YGz0kRvMp3a153du/qEtZ/uEOueWubCMhTSqda6JJSM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lGDJDZG+E7o6j/ZjtYvns+NICJYBE7naqueuuuSCyWtePZDT9NKBXAPRju87LVxzR z3SCh9JLEzxYQ4ZtrW8NR35JWD8EvLo5Lr50LSs4OeGAYdevfgt61FJuTfgoEx4suL hwxn3sjnbSleRHv7xlUPK/P5Ec7zjNHqZ0cQ5TIg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1802186AbgJ0Pp4 (ORCPT ); Tue, 27 Oct 2020 11:45:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:58322 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1801078AbgJ0Pi6 (ORCPT ); Tue, 27 Oct 2020 11:38:58 -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 B76C52225E; Tue, 27 Oct 2020 15:38:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603813138; bh=YGz0kRvMp3a153du/qEtZ/uEOueWubCMhTSqda6JJSM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QIwZwnIsnDL2VTdUTAz1IfOq9l9etNsmj9NbQD3Yvq4Qt351FdAt7W4eyb2nQ3EDu oPjfEzqGtEkrrWvstydm1j57Uuu4qJG670Guyr92emBhh9difPxc1irPEuz+b8lBbF 1pHqt34Fnw3c+7mI05pSfS8jFg1s/sIICiEQfPzo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vaibhav Jain , Ira Weiny , Michael Ellerman , Sasha Levin Subject: [PATCH 5.9 451/757] powerpc/papr_scm: Fix warning triggered by perf_stats_show() Date: Tue, 27 Oct 2020 14:51:41 +0100 Message-Id: <20201027135511.690664716@linuxfoundation.org> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201027135450.497324313@linuxfoundation.org> References: <20201027135450.497324313@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Vaibhav Jain [ Upstream commit ca78ef2f08ccfa29b711d644964cdf9d7ace15e5 ] A warning is reported by the kernel in case perf_stats_show() returns an error code. The warning is of the form below: papr_scm ibm,persistent-memory:ibm,pmemory@44100001: Failed to query performance stats, Err:-10 dev_attr_show: perf_stats_show+0x0/0x1c0 [papr_scm] returned bad count fill_read_buffer: dev_attr_show+0x0/0xb0 returned bad count On investigation it looks like that the compiler is silently truncating the return value of drc_pmem_query_stats() from 'long' to 'int', since the variable used to store the return code 'rc' is an 'int'. This truncated value is then returned back as a 'ssize_t' back from perf_stats_show() to 'dev_attr_show()' which thinks of it as a large unsigned number and triggers this warning.. To fix this we update the type of variable 'rc' from 'int' to 'ssize_t' that prevents the compiler from truncating the return value of drc_pmem_query_stats() and returning correct signed value back from perf_stats_show(). Fixes: 2d02bf835e57 ("powerpc/papr_scm: Fetch nvdimm performance stats from PHYP") Signed-off-by: Vaibhav Jain Reviewed-by: Ira Weiny Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200912081451.66225-1-vaibhav@linux.ibm.com Signed-off-by: Sasha Levin --- arch/powerpc/platforms/pseries/papr_scm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c index a88a707a608aa..5493bc847bd08 100644 --- a/arch/powerpc/platforms/pseries/papr_scm.c +++ b/arch/powerpc/platforms/pseries/papr_scm.c @@ -785,7 +785,8 @@ static int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc, static ssize_t perf_stats_show(struct device *dev, struct device_attribute *attr, char *buf) { - int index, rc; + int index; + ssize_t rc; struct seq_buf s; struct papr_scm_perf_stat *stat; struct papr_scm_perf_stats *stats; @@ -820,7 +821,7 @@ static ssize_t perf_stats_show(struct device *dev, free_stats: kfree(stats); - return rc ? rc : seq_buf_used(&s); + return rc ? rc : (ssize_t)seq_buf_used(&s); } DEVICE_ATTR_ADMIN_RO(perf_stats);