From: Ingo Molnar <mingo@kernel•org>
To: Laurent Dufour <ldufour@linux•vnet.ibm.com>
Cc: linux-arch@vger•kernel.org, linux-s390@vger•kernel.org,
x86@kernel•org, user-mode-linux-devel@lists•sourceforge.net,
Arnd Bergmann <arnd@arndb•de>, Jeff Dike <jdike@addtoit•com>,
"H. Peter Anvin" <hpa@zytor•com>,
linux-kernel@vger•kernel.org, criu@openvz•org,
linux-mm@kvack•org, Ingo Molnar <mingo@redhat•com>,
Paul Mackerras <paulus@samba•org>,
user-mode-linux-user@lists•sourceforge.net,
Richard Weinberger <richard@nod•at>,
Thomas Gleixner <tglx@linutronix•de>,
Guan Xuetao <gxt@mprc•pku.edu.cn>,
linuxppc-dev@lists•ozlabs.org, cov@codeaurora•org
Subject: Re: [PATCH v3 2/2] powerpc/mm: Tracking vDSO remap
Date: Wed, 25 Mar 2015 19:36:47 +0100 [thread overview]
Message-ID: <20150325183647.GA9331@gmail.com> (raw)
In-Reply-To: <20150325183316.GA9090@gmail.com>
* Ingo Molnar <mingo@kernel•org> wrote:
> > +#define __HAVE_ARCH_REMAP
> > +static inline void arch_remap(struct mm_struct *mm,
> > + unsigned long old_start, unsigned long old_end,
> > + unsigned long new_start, unsigned long new_end)
> > +{
> > + /*
> > + * mremap() doesn't allow moving multiple vmas so we can limit the
> > + * check to old_start == vdso_base.
> > + */
> > + if (old_start == mm->context.vdso_base)
> > + mm->context.vdso_base = new_start;
> > +}
>
> mremap() doesn't allow moving multiple vmas, but it allows the
> movement of multi-page vmas and it also allows partial mremap()s,
> where it will split up a vma.
I.e. mremap() supports the shrinking (and growing) of vmas. In that
case mremap() will unmap the end of the vma and will shrink the
remaining vDSO vma.
Doesn't that result in a non-working vDSO that should zero out
vdso_base?
Thanks,
Ingo
next prev parent reply other threads:[~2015-03-25 18:36 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-20 15:53 [PATCH 0/2] Tracking user space vDSO remaping Laurent Dufour
2015-03-20 15:53 ` [PATCH 1/2] mm: Introducing arch_remap hook Laurent Dufour
2015-03-20 23:19 ` Richard Weinberger
2015-03-23 8:52 ` Ingo Molnar
2015-03-23 9:11 ` Laurent Dufour
2015-03-25 11:06 ` [PATCH v2 0/2] Tracking user space vDSO remaping Laurent Dufour
2015-03-25 11:06 ` [PATCH v2 1/2] mm: Introducing arch_remap hook Laurent Dufour
2015-03-25 11:06 ` [PATCH v2 2/2] powerpc/mm: Tracking vDSO remap Laurent Dufour
2015-03-25 12:11 ` Ingo Molnar
2015-03-25 13:25 ` Laurent Dufour
2015-03-25 13:53 ` [PATCH v3 0/2] Tracking user space vDSO remaping Laurent Dufour
2015-03-25 13:53 ` [PATCH v3 1/2] mm: Introducing arch_remap hook Laurent Dufour
2015-03-25 13:53 ` [PATCH v3 2/2] powerpc/mm: Tracking vDSO remap Laurent Dufour
2015-03-25 18:33 ` Ingo Molnar
2015-03-25 18:36 ` Ingo Molnar [this message]
2015-03-25 21:11 ` Benjamin Herrenschmidt
2015-03-26 9:43 ` Ingo Molnar
2015-03-26 10:37 ` Laurent Dufour
2015-03-26 14:17 ` Ingo Molnar
2015-03-26 14:32 ` Laurent Dufour
2015-03-26 17:37 ` [PATCH v4 0/2] Tracking user space vDSO remaping Laurent Dufour
2015-03-26 17:37 ` [PATCH v4 1/2] mm: Introducing arch_remap hook Laurent Dufour
2015-03-26 17:37 ` [PATCH v4 2/2] powerpc/mm: Tracking vDSO remap Laurent Dufour
2015-03-26 18:55 ` Ingo Molnar
2015-03-27 11:02 ` Laurent Dufour
2015-03-26 23:23 ` [PATCH v3 " Benjamin Herrenschmidt
2015-03-25 21:09 ` Benjamin Herrenschmidt
2015-03-26 9:48 ` Ingo Molnar
2015-03-26 10:13 ` Laurent Dufour
2015-03-20 15:53 ` [PATCH " Laurent Dufour
2016-03-02 12:13 ` [PATCH 0/2] Tracking user space vDSO remaping Christopher Covington
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