Re: [PATCH 0/6] enable writing to /proc/pid/mem

[Stephen Wilson]

On Wed, Mar 09, 2011 at 02:33:04AM +0000, Al Viro wrote:
> On Tue, Mar 08, 2011 at 09:15:25PM -0500, Stephen Wilson wrote:
> 
> > I think we could also remove the intermediate copy in both mem_read() and
> > mem_write() as well, but I think such optimizations could be left for
> > follow on patches.
> 
> How?  We do copy_.._user() in there; it can trigger page faults and
> that's not something you want while holding mmap_sem on some mm.

Ah, OK.   I did not think thru that subtlety.  Was merely mentioning
"things we might do afterwords" as opposed to a genuine proposal.

> Looks like a deadlock country...  So we can't do that from inside
> access_process_vm() or its analogs, which means buffering in caller.

Thanks for the feed back -- I am certainly (relatively speaking) new to
the code so your insights are most valuable.

Thanks again!


-- 
steve

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