Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <eecbdc2a-09b3-78bd-9588-ed395190eb39@linux.alibaba.com>
Date:   Wed, 2 Aug 2023 17:47:24 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0)
 Gecko/20100101 Thunderbird/102.11.2
Subject: Re: [PATCH v5 1/5] perf metric: Event "Compat" value supports
 matching multiple identifiers
To:     John Garry <john.g.garry@oracle.com>
Cc:     Ian Rogers <irogers@google.com>, Will Deacon <will@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Ilkka Koskinen <ilkka@os.amperecomputing.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-perf-users@vger.kernel.org, linux-doc@vger.kernel.org,
        Zhuo Song <zhuo.song@linux.alibaba.com>,
        Shuai Xue <xueshuai@linux.alibaba.com>
References: <1690525040-77423-1-git-send-email-renyu.zj@linux.alibaba.com>
 <1690525040-77423-2-git-send-email-renyu.zj@linux.alibaba.com>
 <268b3891-be4b-5f63-eff3-7b6d83e906e9@oracle.com>
 <0801b73c-6649-8c54-8dca-276efc2a4967@linux.alibaba.com>
 <8e207c71-5400-5427-ae83-a1e0b8f95e31@linux.alibaba.com>
 <b471c336-92dc-af42-dfd2-62831fd6dd60@oracle.com>
From:   Jing Zhang <renyu.zj@linux.alibaba.com>
In-Reply-To: <b471c336-92dc-af42-dfd2-62831fd6dd60@oracle.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk


在 2023/8/2 下午5:43, John Garry 写道:
> On 02/08/2023 10:38, Jing Zhang wrote:
>>>>> n;
>>>>> +
>>>>> +    str = strdup(compat);
>>>> why duplicate this? are you modifying something?
>>>>
>>> This is really a redundant step, I will remove it.
>>>
>> Hi John,
>>
>> I reviewed this code again and found that it still needs to duplicate "compat" because "compat" is a
>> const str* type and cannot be used as a parameter for the strtok_r function. If it is cast to char*,
>> using "compat" as a parameter for strtok_r is also unsafe and can cause a "Segmentation fault" error.
>> Therefore, let's keep the step of duplicating "compat".
> 
> ok, so then please add a small comment on why the strdup() call is needed.
> 

No problem.

Thanks,
Jing