From: Matthew Wilcox <willy@infradead.org>
To: Suren Baghdasaryan <surenb@google.com>
Cc: akpm@linux-foundation.org, ccross@google.com,
sumit.semwal@linaro.org, mhocko@suse.com, dave.hansen@intel.com,
keescook@chromium.org, kirill.shutemov@linux.intel.com,
vbabka@suse.cz, hannes@cmpxchg.org, ebiederm@xmission.com,
brauner@kernel.org, legion@kernel.org, ran.xiaokai@zte.com.cn,
sashal@kernel.org, chris.hyser@oracle.com, dave@stgolabs.net,
pcc@google.com, caoxiaofeng@yulong.com, david@redhat.com,
gorcunov@gmail.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, kernel-team@android.com,
syzbot+aa7b3d4b35f9dc46a366@syzkaller.appspotmail.com
Subject: Re: [PATCH v2 1/1] mm: fix use-after-free when anon vma name is used after vma is freed
Date: Thu, 10 Feb 2022 13:27:35 +0000 [thread overview]
Message-ID: <YgUSxzp/qDwLkiKb@casper.infradead.org> (raw)
In-Reply-To: <20220210043215.42794-1-surenb@google.com>
On Wed, Feb 09, 2022 at 08:32:15PM -0800, Suren Baghdasaryan wrote:
> +void vma_anon_name_put(struct anon_vma_name *anon_name)
> +{
> + kref_put(&anon_name->kref, vma_anon_name_free);
> +}
To agree with Michal, make this:
if (anon_name)
kref_put(&anon_name->kref, vma_anon_name_free);
>
> - error = madvise_update_vma(vma, prev, start, end, new_flags,
> - vma_anon_name(vma));
> + anon_name = vma_anon_name_get(vma);
> + if (anon_name) {
> + error = madvise_update_vma(vma, prev, start, end, new_flags,
> + anon_name->name);
> + vma_anon_name_put(anon_name);
> + } else {
> + error = madvise_update_vma(vma, prev, start, end, new_flags,
> + NULL);
> + }
And then this becomes:
anon_name = vma_anon_name_get(vma);
error = madvise_update_vma(vma, prev, start, end, new_flags, anon_name);
vma_anon_name_put(anon_name);
next prev parent reply other threads:[~2022-02-10 13:28 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-10 4:32 [PATCH v2 1/1] mm: fix use-after-free when anon vma name is used after vma is freed Suren Baghdasaryan
2022-02-10 12:40 ` Michal Hocko
2022-02-10 15:18 ` Suren Baghdasaryan
2022-02-10 15:27 ` Matthew Wilcox
2022-02-10 16:00 ` Suren Baghdasaryan
2022-02-10 19:35 ` Matthew Wilcox
2022-02-10 19:52 ` Suren Baghdasaryan
2022-02-11 1:33 ` Suren Baghdasaryan
2022-02-10 13:27 ` Matthew Wilcox [this message]
2022-02-10 15:21 ` Suren Baghdasaryan
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