From: Dan Carpenter <dan.carpenter@oracle.com>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Jan Kara <jack@suse.cz>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Michal Hocko <mhocko@suse.com>,
Lorenzo Stoakes <lstoakes@gmail.com>,
Dan Williams <dan.j.williams@intel.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
linux-mm@kvack.org, kernel-janitors@vger.kernel.org
Subject: Re: [patch v2 linux-next] userfaultfd: hugetlbfs: unmap the correct pointer
Date: Sat, 14 Jan 2017 09:55:29 +0300 [thread overview]
Message-ID: <20170114065529.GE15314@mwanda> (raw)
In-Reply-To: <alpine.LSU.2.11.1701131559360.2443@eggly.anvils>
On Fri, Jan 13, 2017 at 04:02:37PM -0800, Hugh Dickins wrote:
> On Fri, 13 Jan 2017, Dan Carpenter wrote:
>
> > kunmap_atomic() and kunmap() take different pointers. People often get
> > these mixed up.
> >
> > Fixes: 16374db2e9a0 ("userfaultfd: hugetlbfs: fix __mcopy_atomic_hugetlb retry/error processing")
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > ---
> > v2: I was also unmapping the wrong pointer because I had a typo.
> >
> > diff --git a/mm/memory.c b/mm/memory.c
> > index 6012a05..aca8ef6 100644
> > --- a/mm/memory.c
> > +++ b/mm/memory.c
> > @@ -4172,7 +4172,7 @@ long copy_huge_page_from_user(struct page *dst_page,
> > (const void __user *)(src + i * PAGE_SIZE),
> > PAGE_SIZE);
> > if (allow_pagefault)
> > - kunmap(page_kaddr);
> > + kunmap(page_kaddr + i);
> > else
> > kunmap_atomic(page_kaddr);
>
> I think you need to look at that again.
Oh wow... What absolute heck! I can't believe how badly I'm messing
up on this.
regards,
dan carpenter
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prev parent reply other threads:[~2017-01-14 6:56 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-12 19:20 [patch " Dan Carpenter
2017-01-12 19:33 ` Michal Hocko
2017-01-13 8:16 ` Dan Carpenter
2017-01-13 8:26 ` Michal Hocko
2017-01-13 8:40 ` Dan Carpenter
2017-01-13 8:26 ` [patch v2 " Dan Carpenter
2017-01-13 8:40 ` Michal Hocko
2017-01-13 16:29 ` Mike Kravetz
2017-01-14 0:02 ` Hugh Dickins
2017-01-14 0:13 ` Andrew Morton
2017-01-14 6:56 ` Dan Carpenter
2017-01-14 6:55 ` Dan Carpenter [this message]
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