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Date:   Fri, 8 Jul 2022 21:03:35 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Zheng Yejian <zhengyejian1@huawei.com>
Cc:     <mingo@redhat.com>, <linux-kernel@vger.kernel.org>,
        <tom.zanussi@linux.intel.com>, <trix@redhat.com>,
        <stable@vger.kernel.org>, <zhangjinhao2@huawei.com>
Subject: Re: [PATCH] Revert "tracing: fix double free"
Message-ID: <20220708210335.79a38356@gandalf.local.home>
In-Reply-To: <20220630013137.164756-1-zhengyejian1@huawei.com>
References: <20220630013137.164756-1-zhengyejian1@huawei.com>
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On Thu, 30 Jun 2022 09:31:37 +0800
Zheng Yejian <zhengyejian1@huawei.com> wrote:

> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index 48e82e141d54..2784951e0fc8 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -4430,6 +4430,7 @@ static int parse_var_defs(struct hist_trigger_data *hist_data)
>  
>  			s = kstrdup(field_str, GFP_KERNEL);
>  			if (!s) {
> +				kfree(hist_data->attrs->var_defs.name[n_vars]);

Instead of doing just a revert, can we also add, for safety:

				hist_data->attrs->var_defs.name[n_vars] = NULL;

Thanks,

-- Steve

>  				ret = -ENOMEM;
>  				goto free;
>  			}