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Message-ID: <517fae75-c4e7-4576-81ff-6a14a3eb9cd7@kylinos.cn>
Date: Fri, 19 Jan 2024 17:22:25 +0800
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Subject: Re: [PATCH v2] x86/xen: Add some null pointer checking to smp.c
To: Markus Elfring <Markus.Elfring@web.de>, xen-devel@lists.xenproject.org,
 kernel-janitors@vger.kernel.org
Cc: LKML <linux-kernel@vger.kernel.org>, kernel test robot <lkp@intel.com>,
 Boris Ostrovsky <boris.ostrovsky@oracle.com>, Borislav Petkov
 <bp@alien8.de>, Dave Hansen <dave.hansen@linux.intel.com>,
 "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
 =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= <jgross@suse.com>,
 Thomas Gleixner <tglx@linutronix.de>, x86@kernel.org
References: <20240117090018.152031-1-chentao@kylinos.cn>
 <1705655941162581.825.seg@mailgw>
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From: Kunwu Chan <chentao@kylinos.cn>
In-Reply-To: <1705655941162581.825.seg@mailgw>
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On 2024/1/17 18:40, Markus Elfring wrote:
>> kasprintf() returns a pointer to dynamically allocated memory
>> which can be NULL upon failure. Ensure the allocation was successful
>> by checking the pointer validity.
> =E2=80=A6
>> +++ b/arch/x86/xen/smp.c
>> @@ -61,10 +61,14 @@ void xen_smp_intr_free(unsigned int cpu)
>>
>>   int xen_smp_intr_init(unsigned int cpu)
>>   {
>> -	int rc;
>> +	int rc =3D 0;
>=20
> I find the indication of a successful function execution sufficient by
> the statement =E2=80=9Creturn 0;=E2=80=9D at the end.
> How do you think about to omit such an extra variable initialisation?
Thanks, it's no need now. I'll remove it in v3.
>=20
>=20
>>   	char *resched_name, *callfunc_name, *debug_name;
>>
>>   	resched_name =3D kasprintf(GFP_KERNEL, "resched%d", cpu);
>> +	if (!resched_name) {
>> +		rc =3D -ENOMEM;
>> +		goto fail;
>> +	}
>>   	per_cpu(xen_resched_irq, cpu).name =3D resched_name;
>>   	rc =3D bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
>>   				    cpu,
>=20
> You propose to apply the same error code in four if branches.
> I suggest to avoid the specification of duplicate assignment statements
> for this purpose.
> How do you think about to use another label like =E2=80=9Ce_nomem=E2=80=
=9D?
I'll add a new label to simply the code.
>=20
> Regards,
> Markus
--=20
Thanks,
   Kunwu