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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A3932E81DF7 for ; Fri, 6 Oct 2023 13:01:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232313AbjJFNBT (ORCPT ); Fri, 6 Oct 2023 09:01:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232430AbjJFNBD (ORCPT ); Fri, 6 Oct 2023 09:01:03 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2DFAC10F0; Fri, 6 Oct 2023 06:00:28 -0700 (PDT) Received: from pps.filterd (m0353727.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 396Cm2Yi027588; Fri, 6 Oct 2023 13:00:26 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : references : date : in-reply-to : message-id : mime-version : content-type; s=pp1; bh=bYY3YhVBnbQhx5HFvODLAVARQ2hrt7AtExXhXmnuCmc=; b=UvfJBi6twavdh6VuM7py0/MJogO2UoNLGYDznpZNJONODZ+/AHltUs0x3gwUUrtZ6htV nKbs4yuMoDZQ7HqFDygGvx4hnPUDAq5L9fnZOexfKNHXtjcr604QsqS+Srh3YcKP8MPo 4em9dQsifQzZf05XPwoFFTH9M6g9XgQJXY58RHyS79aen2v6hP/h3fzUucO3uoJ8ZFws 5Pk1uny+5g3bkCDtuERkI8IJj/t88v9pXVXZV1ZpEqnEd43UbLdWXPpANV8LyIITTkeU NzCJZbgirM9HBxVn2gF5TfbFrmNCmRsTGKDJZJLCq9CGG9UP6YI0IQqLgNYkwP9m/mRy Og== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3tjjj70fn5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 06 Oct 2023 13:00:25 +0000 Received: from m0353727.ppops.net (m0353727.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 396CmiNE029118; Fri, 6 Oct 2023 12:59:11 GMT Received: from ppma11.dal12v.mail.ibm.com (db.9e.1632.ip4.static.sl-reverse.com [50.22.158.219]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3tjjj70dum-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 06 Oct 2023 12:59:11 +0000 Received: from pps.filterd (ppma11.dal12v.mail.ibm.com [127.0.0.1]) by ppma11.dal12v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 396Co7oo010941; Fri, 6 Oct 2023 12:54:06 GMT Received: from smtprelay07.fra02v.mail.ibm.com ([9.218.2.229]) by ppma11.dal12v.mail.ibm.com (PPS) with ESMTPS id 3tf0q32wes-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 06 Oct 2023 12:54:06 +0000 Received: from smtpav07.fra02v.mail.ibm.com (smtpav07.fra02v.mail.ibm.com [10.20.54.106]) by smtprelay07.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 396Cs4eH65470872 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 6 Oct 2023 12:54:04 GMT Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 95EDF20040; Fri, 6 Oct 2023 12:54:04 +0000 (GMT) Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 731662004B; Fri, 6 Oct 2023 12:54:04 +0000 (GMT) Received: from tuxmaker.linux.ibm.com (unknown [9.152.85.9]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTPS; Fri, 6 Oct 2023 12:54:04 +0000 (GMT) From: Sven Schnelle To: Mateusz Guzik Cc: Mark Brown , Christian Brauner , Jann Horn , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: Test failure from "file: convert to SLAB_TYPESAFE_BY_RCU" References: <00e5cc23-a888-46ce-8789-fc182a2131b0@sirena.org.uk> Date: Fri, 06 Oct 2023 14:54:04 +0200 In-Reply-To: (Mateusz Guzik's message of "Fri, 6 Oct 2023 14:39:21 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 71RIwD2D7PaWMMg9nMWSBGc6cV0z4AY0 X-Proofpoint-GUID: Y-SGr6yrQUi3vyfhwUSYbiM_p6srS_3k X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.980,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-10-06_10,2023-10-06_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=579 suspectscore=0 clxscore=1015 malwarescore=0 phishscore=0 spamscore=0 adultscore=0 impostorscore=0 priorityscore=1501 lowpriorityscore=0 mlxscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2309180000 definitions=main-2310060096 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mateusz Guzik writes: > On Fri, Oct 06, 2023 at 11:19:58AM +0200, Sven Schnelle wrote: >> I'm seeing the same with the strace test-suite on s390. The problem is >> that /proc/*/fd now contains the file descriptors of the calling >> process, and not the target process. >> > > This is why: > > +static inline struct file *files_lookup_fdget_rcu(struct files_struct *files, unsigned int fd) > +{ > + RCU_LOCKDEP_WARN(!rcu_read_lock_held(), > + "suspicious rcu_dereference_check() usage"); > + return lookup_fdget_rcu(fd); > +} > > files argument is now thrown away, instead it always uses current. Yes, passing files to lookup_fdget_rcu() fixes the issue.