From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f72.google.com (mail-pl0-f72.google.com [209.85.160.72]) by kanga.kvack.org (Postfix) with ESMTP id 9BED36B0003 for ; Tue, 17 Apr 2018 01:11:09 -0400 (EDT) Received: by mail-pl0-f72.google.com with SMTP id e8-v6so4834430plb.5 for ; Mon, 16 Apr 2018 22:11:09 -0700 (PDT) Received: from smtp.codeaurora.org (smtp.codeaurora.org. [198.145.29.96]) by mx.google.com with ESMTPS id t2si11082664pgb.338.2018.04.16.22.11.08 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 16 Apr 2018 22:11:08 -0700 (PDT) Subject: Re: [PATCH 2/2] mm: vmalloc: Pass proper vm_start into debugobjects References: <1523619234-17635-1-git-send-email-cpandya@codeaurora.org> <1523619234-17635-3-git-send-email-cpandya@codeaurora.org> <72acd72a-7b92-c723-62d8-28dd81435457@codeaurora.org> From: Chintan Pandya Message-ID: <89438471-6e47-cb70-8909-0ffcc2d3e313@codeaurora.org> Date: Tue, 17 Apr 2018 10:40:57 +0530 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Anshuman Khandual , 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 Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org On 4/17/2018 8:39 AM, Anshuman Khandual wrote: > On 04/16/2018 05:39 PM, Chintan Pandya wrote: >> >> >> On 4/13/2018 5:31 PM, Anshuman Khandual wrote: >>> 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 >> Right, I missed it. I plan to add below stub in v2. >> >> --- a/mm/vmalloc.c >> +++ b/mm/vmalloc.c >> @@ -1124,15 +1124,15 @@ void vm_unmap_ram(const void *mem, unsigned int >> count) >> BUG_ON(addr > VMALLOC_END); >> BUG_ON(!PAGE_ALIGNED(addr)); >> >> - debug_check_no_locks_freed(mem, size); >> - >> if (likely(count <= VMAP_MAX_ALLOC)) { >> + debug_check_no_locks_freed(mem, size); > > It should have been 'va->va_start' instead of 'mem' in here but as > said before it looks correct to me but I am not really sure. vb_free() doesn't honor va->va_start. If mem is not va_start and deliberate, one will provide proper size. And that should be okay to do as per the code. So, I don't think this particular debug_check should have passed va_start in args. > Chintan -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project