netdev - Re: [ovs-discuss] Double free in recent kernels after memleak fix

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Message-ID: <CAM_iQpXBHSYdqb8Q3ifG8uwa1YfJmGBexHC2BusRoshU0M5X5g@mail.gmail.com>
Date:   Mon, 10 Aug 2020 19:24:37 -0700
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     Tonghao Zhang <xiangxia.m.yue@...il.com>
Cc:     "Paul E . McKenney" <paulmck@...nel.org>,
        Joel Fernandes <joel@...lfernandes.org>,
        Johan Knöös <jknoos@...gle.com>,
        Gregory Rose <gvrose8192@...il.com>,
        bugs <bugs@...nvswitch.org>, Netdev <netdev@...r.kernel.org>,
        "Uladzislau Rezki (Sony)" <urezki@...il.com>,
        rcu <rcu@...r.kernel.org>
Subject: Re: [ovs-discuss] Double free in recent kernels after memleak fix

On Mon, Aug 10, 2020 at 6:16 PM Tonghao Zhang <xiangxia.m.yue@...il.com> wrote:
> Hi all, I send a patch to fix this. The rcu warnings disappear. I
> don't reproduce the double free issue.
> But I guess this patch may address this issue.
>
> http://patchwork.ozlabs.org/project/netdev/patch/20200811011001.75690-1-xiangxia.m.yue@gmail.com/

I don't see how your patch address the double-free, as we still
free mask array twice after your patch: once in tbl_mask_array_realloc()
and once in ovs_flow_tbl_destroy().

Have you tried my patch which is supposed to address this double-free?
It simply skips the reallocation as it makes no sense to trigger reallocation
when destroying it.

Thanks.