linux-kernel - Re: [PATCH 1/3] mm/hugetlb: Fix race condition of uffd missing/minor handling

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <568C0BF2-28B9-438C-93D2-19130FAA3364@gmail.com>
Date:   Mon, 3 Oct 2022 14:32:31 -0700
From:   Nadav Amit <nadav.amit@...il.com>
To:     Peter Xu <peterx@...hat.com>
Cc:     LKML <linux-kernel@...r.kernel.org>, Linux MM <linux-mm@...ck.org>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        David Hildenbrand <david@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Axel Rasmussen <axelrasmussen@...gle.com>,
        Mike Kravetz <mike.kravetz@...cle.com>
Subject: Re: [PATCH 1/3] mm/hugetlb: Fix race condition of uffd missing/minor
 handling

On Oct 3, 2022, at 2:16 PM, Peter Xu <peterx@...hat.com> wrote:

> On Mon, Oct 03, 2022 at 02:00:36PM -0700, Nadav Amit wrote:
>> On Oct 3, 2022, at 8:56 AM, Peter Xu <peterx@...hat.com> wrote:
>> 
>>> +			 */
>>> +			if (hugetlb_pte_stable(h, mm, ptep, old_pte))
>>> +				ret = hugetlb_handle_userfault(
>>> +				    vma, mapping, idx, flags, haddr,
>>> +				    address, VM_UFFD_MISSING);
>>> +			else
>>> +				/* Retry the fault */
>>> +				ret = 0;
>> 
>> Might be unrelated, but at least for the sake of consistency if not
>> potential GUP issues, don’t you want to return VM_FAULT_RETRY ?
> 
> VM_FAULT_RETRY implies releasing of mmap sem, while we didn't?

Of course. My bad.