From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754100AbeDMMCG (ORCPT ); Fri, 13 Apr 2018 08:02:06 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:44404 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751421AbeDMMCE (ORCPT ); Fri, 13 Apr 2018 08:02:04 -0400 Subject: Re: [PATCH 2/2] mm: vmalloc: Pass proper vm_start into debugobjects To: Chintan Pandya , vbabka@suse.cz, labbott@redhat.com, catalin.marinas@arm.com, hannes@cmpxchg.org, f.fainelli@gmail.com, xieyisheng1@huawei.com, ard.biesheuvel@linaro.org, richard.weiyang@gmail.com, byungchul.park@lge.com References: <1523619234-17635-1-git-send-email-cpandya@codeaurora.org> <1523619234-17635-3-git-send-email-cpandya@codeaurora.org> Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org From: Anshuman Khandual Date: Fri, 13 Apr 2018 17:31:49 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <1523619234-17635-3-git-send-email-cpandya@codeaurora.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 18041312-0020-0000-0000-000004118643 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18041312-0021-0000-0000-000042A5B8BC Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-13_05:,, 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 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804130113 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/13/2018 05:03 PM, Chintan Pandya wrote: > Client can call vunmap with some intermediate 'addr' > which may not be the start of the VM area. Entire > unmap code works with vm->vm_start which is proper > but debug object API is called with 'addr'. This > could be a problem within debug objects. > > Pass proper start address into debug object API. > > Signed-off-by: Chintan Pandya > --- > mm/vmalloc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 9ff21a1..28034c55 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -1526,8 +1526,8 @@ static void __vunmap(const void *addr, int deallocate_pages) > return; > } > > - debug_check_no_locks_freed(addr, get_vm_area_size(area)); > - debug_check_no_obj_freed(addr, get_vm_area_size(area)); > + debug_check_no_locks_freed(area->addr, get_vm_area_size(area)); > + debug_check_no_obj_freed(area->addr, get_vm_area_size(area)); This kind of makes sense to me but I am not sure. We also have another instance of this inside the function vm_unmap_ram() where we call for debug on locks without even finding the vmap_area first. But it is true that in both these functions the vmap_area gets freed eventually. Hence the entire mapping [va->va_start --> va->va_end] gets unmapped. Sounds like these debug functions should have the entire range as argument. But I am not sure and will seek Michal's input on this.