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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 376D4C10F13 for ; Thu, 11 Apr 2019 05:41:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E0F112133D for ; Thu, 11 Apr 2019 05:41:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726771AbfDKFlu (ORCPT ); Thu, 11 Apr 2019 01:41:50 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:56762 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726104AbfDKFlu (ORCPT ); Thu, 11 Apr 2019 01:41:50 -0400 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x3B5cYCS029861 for ; Thu, 11 Apr 2019 01:41:49 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2rswfgcwv3-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 11 Apr 2019 01:41:48 -0400 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 11 Apr 2019 06:41:43 +0100 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x3B5fgAT51642474 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 11 Apr 2019 05:41:42 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5EDE1A4059; Thu, 11 Apr 2019 05:41:42 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id F22A7A404D; Thu, 11 Apr 2019 05:41:40 +0000 (GMT) Received: from skywalker.linux.ibm.com (unknown [9.85.73.26]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 11 Apr 2019 05:41:40 +0000 (GMT) X-Mailer: emacs 26.1 (via feedmail 11-beta-1 I) From: "Aneesh Kumar K.V" To: Christophe Leroy , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v1 03/27] powerpc/mm: don't BUG() in slice_mask_for_size() In-Reply-To: References: Date: Thu, 11 Apr 2019 11:11:39 +0530 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 x-cbid: 19041105-0016-0000-0000-0000026D9812 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19041105-0017-0000-0000-000032C9CAE7 Message-Id: <87lg0h3xpo.fsf@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-04-11_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904110040 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Christophe Leroy writes: > When no mask is found for the page size, WARN() and return NULL > instead of BUG()ing. > > Signed-off-by: Christophe Leroy > --- > arch/powerpc/mm/slice.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c > index aec91dbcdc0b..011d470ea340 100644 > --- a/arch/powerpc/mm/slice.c > +++ b/arch/powerpc/mm/slice.c > @@ -165,7 +165,8 @@ static struct slice_mask *slice_mask_for_size(struct mm_struct *mm, int psize) > if (psize == MMU_PAGE_16G) > return &mm->context.mask_16g; > #endif > - BUG(); > + WARN_ON(true); > + return NULL; > } Same here. There are not catching runtime errors. We should never find that true. This is to catch mistakes during development changes. Switch to VM_BUG_ON? > #elif defined(CONFIG_PPC_8xx) > static struct slice_mask *slice_mask_for_size(struct mm_struct *mm, int psize) > @@ -178,7 +179,8 @@ static struct slice_mask *slice_mask_for_size(struct mm_struct *mm, int psize) > if (psize == MMU_PAGE_8M) > return &mm->context.mask_8m; > #endif > - BUG(); > + WARN_ON(true); > + return NULL; > } > #else > #error "Must define the slice masks for page sizes supported by the platform" > -- > 2.13.3