linux-kernel - Re: [PATCH 1/6] mm: khugepaged: fix radix tree node leak in shmem collapse error path

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20161114194054.GA12829@node.shutemov.name>
Date:   Mon, 14 Nov 2016 22:40:54 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Johannes Weiner <hannes@...xchg.org>
Cc:     Jan Kara <jack@...e.cz>, Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        kernel-team@...com
Subject: Re: [PATCH 1/6] mm: khugepaged: fix radix tree node leak in shmem
 collapse error path

On Mon, Nov 14, 2016 at 11:48:22AM -0500, Johannes Weiner wrote:
> On Mon, Nov 14, 2016 at 10:52:50AM -0500, Johannes Weiner wrote:
> > On Mon, Nov 14, 2016 at 05:29:02PM +0300, Kirill A. Shutemov wrote:
> > > @@ -1400,7 +1400,9 @@ static void collapse_shmem(struct mm_struct *mm,
> > >  					PAGE_SIZE, 0);
> > >  
> > >  		spin_lock_irq(&mapping->tree_lock);
> > > -
> > > +		slot = radix_tree_lookup_slot(&mapping->page_tree, index);
> > > +		VM_BUG_ON_PAGE(page != radix_tree_deref_slot_protected(slot,
> > > +					&mapping->tree_lock), page);
> > >  		VM_BUG_ON_PAGE(page_mapped(page), page);
> > 
> > That looks good to me. The slot may get relocated, but the content
> > shouldn't change with the page locked.
> > 
> > Are you going to send a full patch with changelog and sign-off? If so,
> > please add:
> > 
> > Acked-by: Johannes Weiner <hannes@...xchg.org>
> 
> Just to clarify, this is in addition to my radix_tree_iter_next()
> change. The iterator still needs to be reloaded because the number of
> valid slots that come after the current one can change as well.

Could you just amend all these fixups into your patch?

-- 
 Kirill A. Shutemov