From: Jann Horn <jannh@google.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michal Hocko" <mhocko@suse.com>, Linux-MM <linux-mm@kvack.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Khalid Aziz" <khalid.aziz@oracle.com>,
"Russell King - ARM Linux" <linux@armlinux.org.uk>,
"Andrea Arcangeli" <aarcange@redhat.com>,
"Florian Weimer" <fweimer@redhat.com>,
"John Hubbard" <jhubbard@nvidia.com>,
"Matthew Wilcox" <willy@infradead.org>,
abdhalee@linux.vnet.ibm.com, joel@jms.id.au,
"Kees Cook" <keescook@chromium.org>,
"Jason Evans" <jasone@google.com>,
"David Goldblatt" <davidtgoldblatt@gmail.com>,
"Edward Tomasz Napierała" <trasz@freebsd.org>,
"Anshuman Khandual" <khandual@linux.vnet.ibm.com>,
"Daniel Micay" <danielmicay@gmail.com>,
"kernel list" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: don't clobber partially overlapping VMA with MAP_FIXED_NOREPLACE
Date: Fri, 12 Oct 2018 14:09:52 +0200 [thread overview]
Message-ID: <CAG48ez1gc2aKWAhmtLjXB6pSGP75JKNVbBvk_1ZcHO5OM4XhfA@mail.gmail.com> (raw)
In-Reply-To: <87tvlr1n1i.fsf@concordia.ellerman.id.au>
On Fri, Oct 12, 2018 at 12:23 PM Michael Ellerman <mpe@ellerman.id.au> wrote:
> Jann Horn <jannh@google.com> writes:
> > On Wed, Oct 10, 2018 at 7:19 PM Michal Hocko <mhocko@suse.com> wrote:
> >> On Wed 10-10-18 17:27:36, Jann Horn wrote:
> >> > Daniel Micay reports that attempting to use MAP_FIXED_NOREPLACE in an
> >> > application causes that application to randomly crash. The existing check
> >> > for handling MAP_FIXED_NOREPLACE looks up the first VMA that either
> >> > overlaps or follows the requested region, and then bails out if that VMA
> >> > overlaps *the start* of the requested region. It does not bail out if the
> >> > VMA only overlaps another part of the requested region.
> >>
> >> I do not understand. Could you give me an example?
> >
> > Sure.
> >
> > =======
> > user@debian:~$ cat mmap_fixed_simple.c
> > #include <sys/mman.h>
> > #include <errno.h>
> > #include <stdio.h>
> > #include <stdlib.h>
> > #include <unistd.h>
>
> ..
>
> Mind if I turn that into a selftest?
Feel free to do that. :)
next prev parent reply other threads:[~2018-10-12 12:10 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-10 15:27 Jann Horn
2018-10-10 17:19 ` Michal Hocko
2018-10-10 17:26 ` Jann Horn
2018-10-10 17:38 ` Michal Hocko
2018-10-10 18:03 ` John Hubbard
2018-10-10 18:17 ` John Hubbard
2018-10-12 10:23 ` Michael Ellerman
2018-10-12 12:09 ` Jann Horn [this message]
2018-10-10 18:36 ` Kees Cook
2018-10-12 12:03 ` Vlastimil Babka
2018-10-15 7:47 ` Khalid Aziz
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