From: Johannes Weiner <hannes@cmpxchg.org>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Jan Kara <jack@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team@fb.com
Subject: Re: [PATCH 1/6] mm: khugepaged: fix radix tree node leak in shmem collapse error path
Date: Mon, 14 Nov 2016 11:48:22 -0500 [thread overview]
Message-ID: <20161114164822.GB5141@cmpxchg.org> (raw)
In-Reply-To: <20161114155250.GB3291@cmpxchg.org>
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@cmpxchg.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.
next prev parent reply other threads:[~2016-11-14 16:48 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-07 19:07 [PATCH 0/6] mm: workingset: radix tree subtleties & single-page file refaults Johannes Weiner
2016-11-07 19:07 ` [PATCH 1/6] mm: khugepaged: fix radix tree node leak in shmem collapse error path Johannes Weiner
2016-11-08 9:53 ` Jan Kara
2016-11-08 16:12 ` Johannes Weiner
2016-11-09 7:41 ` Jan Kara
2016-11-11 10:59 ` Kirill A. Shutemov
2016-11-11 12:22 ` Jan Kara
2016-11-11 16:37 ` Kirill A. Shutemov
2016-11-14 8:07 ` Jan Kara
2016-11-14 14:29 ` Kirill A. Shutemov
2016-11-14 15:52 ` Johannes Weiner
2016-11-14 16:48 ` Johannes Weiner [this message]
2016-11-14 19:40 ` Kirill A. Shutemov
2016-11-15 14:00 ` Johannes Weiner
2016-11-07 19:07 ` [PATCH 2/6] mm: workingset: turn shadow node shrinker bugs into warnings Johannes Weiner
2016-11-08 9:57 ` Jan Kara
2016-11-07 19:07 ` [PATCH 3/6] lib: radix-tree: native accounting of exceptional entries Johannes Weiner
2016-11-08 10:08 ` Jan Kara
2016-11-07 19:07 ` [PATCH 4/6] lib: radix-tree: check accounting of existing slot replacement users Johannes Weiner
2016-11-08 10:12 ` Jan Kara
2016-11-07 19:07 ` [PATCH 5/6] mm: workingset: switch shadow entry tracking to radix tree exceptional counting Johannes Weiner
2016-11-08 10:27 ` Jan Kara
2016-11-08 19:30 ` Johannes Weiner
2016-11-07 19:07 ` [PATCH 6/6] mm: workingset: restore refault tracking for single-page files Johannes Weiner
2016-11-08 10:31 ` Jan Kara
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