[PATCH 4/4] Do not call flush_cache_user_range with mmap_sem held

[Catalin Marinas]

Russell,

On 14 December 2010 21:08, Catalin Marinas <catalin.marinas at arm.com> wrote:
> On Tuesday, 14 December 2010, Russell King - ARM Linux
> <linux at 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?
That's the original post if you no longer have it in your inbox:

http://article.gmane.org/gmane.linux.ports.arm.kernel/99356

-- 
Catalin