From: Russell King <rmk@arm.linux.org.uk>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Avi Kivity <avi@redhat.com>, Thomas Gleixner <tglx@linutronix.de>,
Rik van Riel <riel@redhat.com>, Ingo Molnar <mingo@elte.hu>,
akpm@linux-foundation.org,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linux-mm@kvack.org,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
David Miller <davem@davemloft.net>,
Hugh Dickins <hugh.dickins@tiscali.co.uk>,
Mel Gorman <mel@csn.ul.ie>, Nick Piggin <npiggin@kernel.dk>,
Paul McKenney <paulmck@linux.vnet.ibm.com>,
Yanmin Zhang <yanmin_zhang@linux.intel.com>,
"Luck,Tony" <tony.luck@intel.com>,
PaulMundt <lethal@linux-sh.org>,
Chris Metcalf <cmetcalf@tilera.com>
Subject: Re: [PATCH 06/17] arm: mmu_gather rework
Date: Mon, 28 Feb 2011 14:57:50 +0000 [thread overview]
Message-ID: <20110228145750.GA4911@flint.arm.linux.org.uk> (raw)
In-Reply-To: <1298902727.2428.10867.camel@twins>
On Mon, Feb 28, 2011 at 03:18:47PM +0100, Peter Zijlstra wrote:
> On Mon, 2011-02-28 at 12:44 +0100, Peter Zijlstra wrote:
> > unmap_region()
> > tlb_gather_mmu()
> > unmap_vmas()
> > for (; vma; vma = vma->vm_next)
> > unmao_page_range()
> > tlb_start_vma() -> flush cache range
>
> So why is this correct? Can't we race with a concurrent access to the
> memory region (munmap() vs other thread access race)? While
> unmap_region() callers will have removed the vma from the tree so faults
> will not be satisfied, TLBs might still be present and allow us to
> access the memory and thereby reloading it in the cache.
It is my understanding that code sections between tlb_gather_mmu() and
tlb_finish_mmu() are non-preemptible - that was the case once upon a
time when this stuff first appeared. If that's changed then that
change has introduced an unnoticed bug.
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of:
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next prev parent reply other threads:[~2011-02-28 14:59 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-17 16:23 [PATCH 00/17] mm: mmu_gather rework Peter Zijlstra
2011-02-17 16:23 ` [PATCH 01/17] tile: Fix __pte_free_tlb Peter Zijlstra
2011-02-17 16:23 ` [PATCH 02/17] mm: mmu_gather rework Peter Zijlstra
2011-03-10 15:50 ` Mel Gorman
2011-03-16 18:55 ` Peter Zijlstra
2011-03-16 20:15 ` Geert Uytterhoeven
2011-03-16 21:08 ` Peter Zijlstra
2011-03-21 8:47 ` Avi Kivity
2011-04-01 12:07 ` Peter Zijlstra
2011-04-01 16:13 ` Linus Torvalds
2011-04-02 0:07 ` David Miller
2011-02-17 16:23 ` [PATCH 03/17] powerpc: " Peter Zijlstra
2011-02-17 16:23 ` [PATCH 04/17] sparc: " Peter Zijlstra
2011-02-17 16:23 ` [PATCH 05/17] s390: " Peter Zijlstra
2011-02-17 16:23 ` [PATCH 06/17] arm: " Peter Zijlstra
2011-02-24 16:34 ` Peter Zijlstra
2011-02-25 18:04 ` Peter Zijlstra
2011-02-25 19:45 ` Peter Zijlstra
2011-02-25 19:59 ` Hugh Dickins
2011-02-25 21:51 ` Russell King
2011-02-28 11:44 ` Peter Zijlstra
2011-02-28 11:59 ` Russell King
2011-02-28 12:06 ` Russell King
2011-02-28 12:25 ` Peter Zijlstra
2011-02-28 12:06 ` Russell King
2011-02-28 12:20 ` Peter Zijlstra
2011-02-28 12:28 ` Russell King
2011-02-28 12:49 ` Peter Zijlstra
2011-02-28 12:50 ` Russell King
2011-02-28 13:03 ` Peter Zijlstra
2011-02-28 14:18 ` Peter Zijlstra
2011-02-28 14:57 ` Russell King [this message]
2011-02-28 15:05 ` Peter Zijlstra
2011-02-28 15:15 ` Russell King
2011-03-01 22:05 ` Chris Metcalf
2011-03-02 10:54 ` Peter Zijlstra
2011-02-17 16:23 ` [PATCH 07/17] sh: " Peter Zijlstra
2011-02-17 16:23 ` [PATCH 08/17] um: " Peter Zijlstra
2011-02-17 16:23 ` [PATCH 09/17] ia64: " Peter Zijlstra
2011-02-17 16:23 ` [PATCH 10/17] mm: Now that all old mmu_gather code is gone, remove the storage Peter Zijlstra
2011-02-17 16:23 ` [PATCH 11/17] mm, powerpc: Move the RCU page-table freeing into generic code Peter Zijlstra
2011-02-17 16:23 ` [PATCH 12/17] s390: use generic RCP page-table freeing Peter Zijlstra
2011-02-17 16:23 ` [PATCH 13/17] mm: Extended batches for generic mmu_gather Peter Zijlstra
2011-02-17 16:23 ` [PATCH 14/17] mm: Provide generic range tracking and flushing Peter Zijlstra
2011-02-17 16:23 ` [PATCH 15/17] arm, mm: Convert arm to generic tlb Peter Zijlstra
2011-02-17 16:23 ` [PATCH 16/17] ia64, mm: Convert ia64 " Peter Zijlstra
2011-02-17 16:23 ` [PATCH 17/17] sh, mm: Convert sh " Peter Zijlstra
2011-02-17 17:36 ` [PATCH 00/17] mm: mmu_gather rework Peter Zijlstra
2011-02-17 17:42 ` Peter Zijlstra
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