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From:   Michael Ellerman <mpe@ellerman.id.au>
To:     Qinglang Miao <miaoqinglang@huawei.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>
Cc:     linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        Qinglang Miao <miaoqinglang@huawei.com>
Subject: Re: [PATCH 2/3] powerpc/pseries/hotplug-cpu: fix memleak in dlpar_cpu_add_by_count
In-Reply-To: <20201128102001.95323-1-miaoqinglang@huawei.com>
References: <20201128102001.95323-1-miaoqinglang@huawei.com>
Date:   Mon, 30 Nov 2020 12:51:44 +1100
Message-ID: <871rgby5lb.fsf@mpe.ellerman.id.au>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Qinglang Miao <miaoqinglang@huawei.com> writes:
> kfree(cpu_drcs) should be called when it fails to perform
> of_find_node_by_path("/cpus") in dlpar_cpu_add_by_count,
> otherwise there would be a memleak.
>
> In fact, the patch a0ff72f9f5a7 ought to remove kfree in
> find_dlpar_cpus_to_add rather than dlpar_cpu_add_by_count.
> I guess there might be a mistake when apply that one.
>
> Fixes: a0ff72f9f5a7 ("powerpc/pseries/hotplug-cpu: Remove double free in error path")
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
> ---
>  arch/powerpc/platforms/pseries/hotplug-cpu.c | 1 +
>  1 file changed, 1 insertion(+)

This is already fixed in my next by:

  a40fdaf1420d ("Revert "powerpc/pseries/hotplug-cpu: Remove double free in error path"")

cheers

> diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
> index f2837e33b..4bb1c9f2b 100644
> --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
> +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
> @@ -743,6 +743,7 @@ static int dlpar_cpu_add_by_count(u32 cpus_to_add)
>  	parent = of_find_node_by_path("/cpus");
>  	if (!parent) {
>  		pr_warn("Could not find CPU root node in device tree\n");
> +		kfree(cpu_drcs);
>  		return -1;
>  	}
>  
> -- 
> 2.23.0