Messages in this thread | | | Date | Mon, 28 Feb 2011 14:57:50 +0000 | From | Russell King <> | Subject | Re: [PATCH 06/17] arm: mmu_gather rework |
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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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