lkml.org 
[lkml]   [2013]   [Dec]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: bad page state in 3.13-rc4
On Fri, Dec 20, 2013 at 04:45:38AM +0900, Linus Torvalds wrote:
> On Fri, Dec 20, 2013 at 4:26 AM, Benjamin LaHaise <bcrl@kvack.org> wrote:
> >
> > Okay, I'll rewriting it to use truncate to free the pages.
>
> It already does that in put_aio_ring_file() afaik. No?

Yes, that's what I found when I started looking into this in detail again.
I think the page reference counting is actually correct. There are 2
references on each page: the first is from the find_or_create_page() call,
and the second is from the get_user_pages() (which also makes sure the page
is populated into the page tables). The only place I can see things going
off the rails is if the get_user_pages() call fails. It's possible trinity
could be arranging things so that the get_user_pages() call is failing
somehow. Also, if it were a double free of a page, we should at least get
a VM_BUG() occuring when the page's count is 0.

Dave -- do you have CONFIG_DEBUG_VM on in your test rig?

> Linus

--
"Thought is the essence of where you are now."


\
 
 \ /
  Last update: 2013-12-20 02:41    [W:0.427 / U:0.120 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site