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From:   Michel Lespinasse <walken@google.com>
Date:   Thu, 4 Jun 2020 01:38:18 -0700
Message-ID: <CANN689GvTF75Knsc82PGrwA44J+yx2ORP-i3fp36avMuxRPwdg@mail.gmail.com>
Subject: Re: [PATCH v6 10/12] mmap locking API: rename mmap_sem to mmap_lock
To:     youling 257 <youling257@gmail.com>
Cc:     "Liam R . Howlett" <Liam.Howlett@oracle.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Daniel Jordan <daniel.m.jordan@oracle.com>,
        Davidlohr Bueso <dave@stgolabs.net>,
        Hugh Dickins <hughd@google.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Jerome Glisse <jglisse@redhat.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Laurent Dufour <ldufour@linux.ibm.com>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-mm <linux-mm@kvack.org>,
        Peter Zijlstra <peterz@infradead.org>,
        David Rientjes <rientjes@google.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Matthew Wilcox <willy@infradead.org>,
        Ying Han <yinghan@google.com>
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On Thu, Jun 4, 2020 at 1:16 AM youling 257 <youling257@gmail.com> wrote:
> 2020-06-04 13:57 GMT+08:00, Michel Lespinasse <walken@google.com>:
> > However I would like more information about your report. Did you apply
> > the series yourself ? If so, what base tree did you apply it onto ? If
> > not, what tree did you use that already included the series ?
>
> I build linux next-20200603 tree have the kernel/sys.c error.

Thanks for the info.

The proper fix is to replace down_write(&mm->mmap_sem) with
mmap_write_lock(mm) and up_write(&mm->mmap_sem) with
mmap_write_unlock(mm)

If you just needed a quick fix to get the tree to build, what you did
(replacing mmap_sem with mmap_lock) is also fine.

Thanks again !

-- 
Michel "Walken" Lespinasse
A program is never fully debugged until the last user dies.