From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 4/4] Do not call flush_cache_user_range with mmap_sem held
Date: Mon, 4 Apr 2011 14:37:18 +0100 [thread overview]
Message-ID: <20110404133718.GC22480@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <BANLkTinmCNi3MgcZo5CJorpoLNxwMwhVOA@mail.gmail.com>
On Mon, Apr 04, 2011 at 02:27:45PM +0100, Catalin Marinas wrote:
> Russell,
>
> On 14 December 2010 21:08, Catalin Marinas <catalin.marinas@arm.com> wrote:
> > On Tuesday, 14 December 2010, Russell King - ARM Linux
> > <linux@arm.linux.org.uk> wrote:
> >> On Tue, Dec 14, 2010 at 05:51:36PM +0000, Catalin Marinas wrote:
> >>> But what's the problem if such mapping disappears? The
> >>> flush_cache_user_range code should just skip such pages.
> >>
> >> That's only half the story.
> >>
> >> What if someone remaps something over that range before the cache
> >> maintainence has completed.
> >
> > That someone remapping the same range can only be a thread of the same
> > process. If the code was so badly written as to unmap ranges of memory
> > when a thread actively uses it, then it probably deserves any
> > corruption.
>
> I haven't seen any more replies in this thread but I still think it's
> a real problem as John reported. Do you agree with the original patch?
No, I do not agree.
next prev parent reply other threads:[~2011-04-04 13:37 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-14 4:57 [PATCH 0/4][RFC] Trivial ARM related Android patches John Stultz
2010-12-14 4:57 ` [PATCH 1/4] avoid mis-detecting some V7 cores in the decompressor John Stultz
2010-12-14 4:57 ` [PATCH 2/4] Optionally flush entire dcache from v6_dma_flush_range John Stultz
2010-12-14 9:30 ` Russell King - ARM Linux
2010-12-14 10:58 ` Catalin Marinas
2010-12-14 4:57 ` [PATCH 3/4] process: Add display of memory around registers when displaying regs John Stultz
2010-12-14 9:34 ` Russell King - ARM Linux
2010-12-14 4:57 ` [PATCH 4/4] Do not call flush_cache_user_range with mmap_sem held John Stultz
2010-12-14 9:30 ` Russell King - ARM Linux
2010-12-14 17:51 ` Catalin Marinas
2010-12-14 19:05 ` Russell King - ARM Linux
2010-12-14 21:08 ` Catalin Marinas
2011-04-04 13:27 ` Catalin Marinas
2011-04-04 13:37 ` Russell King - ARM Linux [this message]
2011-04-04 13:43 ` Catalin Marinas
2011-08-26 7:32 ` Jiejing.Zhang
2011-09-05 11:21 ` Catalin Marinas
2010-12-14 18:18 ` Catalin Marinas
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