From: Andrew Morton <akpm@linux-foundation.org>
To: Rafael Aquini <aquini@redhat.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, ying.huang@intel.com
Subject: Re: [PATCH] mm: swapfile: avoid split_swap_cluster() NULL pointer dereference
Date: Tue, 22 Sep 2020 12:47:50 -0700 [thread overview]
Message-ID: <20200922124750.67a20d9764ec098b17705407@linux-foundation.org> (raw)
In-Reply-To: <20200922184838.978540-1-aquini@redhat.com>
On Tue, 22 Sep 2020 14:48:38 -0400 Rafael Aquini <aquini@redhat.com> wrote:
> The swap area descriptor only gets struct swap_cluster_info *cluster_info
> allocated if the swapfile is backed by non-rotational storage.
> When the swap area is laid on top of ordinary disk spindles, lock_cluster()
> will naturally return NULL.
>
> CONFIG_THP_SWAP exposes cluster_info infrastructure to a broader number of
> use cases, and split_swap_cluster(), which is the counterpart of split_huge_page()
> for the THPs in the swapcache, misses checking the return of lock_cluster before
> operating on the cluster_info pointer.
>
> This patch addresses that issue by adding a proper check for the pointer
> not being NULL in the wrappers cluster_{is,clear}_huge(), in order to avoid
> crashes similar to the one below:
>
> ...
>
> Fixes: 59807685a7e77 ("mm, THP, swap: support splitting THP for THP swap out")
> Signed-off-by: Rafael Aquini <aquini@redhat.com>
Did you consider cc:stable?
next prev parent reply other threads:[~2020-09-22 19:47 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-22 18:48 Rafael Aquini
2020-09-22 19:47 ` Andrew Morton [this message]
2020-09-23 13:42 ` Rafael Aquini
2020-09-25 2:59 ` Andrew Morton
2020-09-25 3:06 ` Huang, Ying
2020-09-25 3:10 ` Andrew Morton
2020-09-23 2:21 ` Huang, Ying
2020-09-23 4:34 ` Rafael Aquini
2020-09-23 5:13 ` Huang, Ying
2020-09-23 13:01 ` Rafael Aquini
2020-09-24 0:59 ` Huang, Ying
2020-09-24 2:09 ` Rafael Aquini
2020-09-24 3:51 ` Huang, Ying
2020-09-24 6:30 ` Rafael Aquini
2020-09-24 6:57 ` Huang, Ying
2020-09-24 7:45 ` Huang, Ying
2020-09-24 15:08 ` Rafael Aquini
2020-09-25 3:21 ` Huang, Ying
2020-09-26 15:16 ` Rafael Aquini
2020-09-27 5:33 ` Huang, Ying
2020-10-01 14:31 ` Rafael Aquini
2020-10-05 13:39 ` Rafael Aquini
2020-10-09 0:18 ` Huang, Ying
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