linux-kernel - Re: [PATCH] ARM: imx: Check return value of devm_kasprintf in imx_mmdc_perf

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Date:   Wed, 22 Nov 2023 14:12:22 +0800
From:   Kunwu Chan <chentao@...inos.cn>
To:     Ahmad Fatoum <a.fatoum@...gutronix.de>, linux@...linux.org.uk,
        shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de,
        festevam@...il.com, linux-imx@....com, angus.chen@...uarmicro.com,
        arnd@...db.de, u.kleine-koenig@...gutronix.de
Cc:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        kunwu.chan@...mail.com
Subject: Re: [PATCH] ARM: imx: Check return value of devm_kasprintf in
 imx_mmdc_perf_init

Hi,Ahmad

Thank you for your guidance to me
It's my bad, i will update a v2 patch follow your suggestions, and send 
it in a new thread.

v2 changes:
1、use the first commit 'e76bdfd7403a' in the 'Fixes' tag.
2、Add new tag 'pmu_release_id' to release the id allocated in 
'mmdc_pmu_init', move 'ida_simple_remove(&mmdc_ida, pmu_mmdc->id);' into 
'pmu_release_id'.

the v2 patch look like:

+       if (!name) {
+               ret = -ENOMEM;
+               goto pmu_release_id;
+       }

         pmu_mmdc->mmdc_ipg_clk = mmdc_ipg_clk;
         pmu_mmdc->devtype_data = (struct fsl_mmdc_devtype_data 
*)of_id->data;
@@ -523,9 +527,10 @@ static int imx_mmdc_perf_init(struct 
platform_device *pdev, void __iomem *mmdc_b

  pmu_register_err:
         pr_warn("MMDC Perf PMU failed (%d), disabled\n", ret);
-       ida_simple_remove(&mmdc_ida, pmu_mmdc->id);
         cpuhp_state_remove_instance_nocalls(cpuhp_mmdc_state, 
&pmu_mmdc->node);
         hrtimer_cancel(&pmu_mmdc->hrtimer);
+pmu_release_id:
+       ida_simple_remove(&mmdc_ida, pmu_mmdc->id);
  pmu_free:


Thanks,
Kunwu

On 2023/11/21 17:37, Ahmad Fatoum wrote:
> Hello Kunwu,
> 
> On 21.11.23 10:25, Kunwu Chan wrote:
>> devm_kasprintf() returns a pointer to dynamically allocated memory
>> which can be NULL upon failure. Ensure the allocation was successful
>> by checking the pointer validity.
>>
>> Fixes: ebeb49f43c89 ("ARM: imx: Call ida_simple_remove() for ida_simple_get")
> 
> This commit only moves the allocation around, but it didn't introduce it.
> Please reference the first commit that added the allocation.
> 
>> Signed-off-by: Kunwu Chan <chentao@...inos.cn>
>> ---
>>   arch/arm/mach-imx/mmdc.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/arch/arm/mach-imx/mmdc.c b/arch/arm/mach-imx/mmdc.c
>> index 2157493b78a9..7c471d6a851d 100644
>> --- a/arch/arm/mach-imx/mmdc.c
>> +++ b/arch/arm/mach-imx/mmdc.c
>> @@ -501,6 +501,10 @@ static int imx_mmdc_perf_init(struct platform_device *pdev, void __iomem *mmdc_b
>>   
>>   	name = devm_kasprintf(&pdev->dev,
>>   				GFP_KERNEL, "mmdc%d", ret);
>> +	if (!name) {
>> +		ret = -ENOMEM;
>> +		goto pmu_free;
> 
> Cleanup is incomplete if you goto pmu_free, e.g. ida_simple_remove()
> isn't called. pmu_register_err does too much cleanup, so you'll need
> to add a new cleanup label.
> 
> Cheers,
> Ahmad
> 
> 
>> +	}
>>   
>>   	pmu_mmdc->mmdc_ipg_clk = mmdc_ipg_clk;
>>   	pmu_mmdc->devtype_data = (struct fsl_mmdc_devtype_data *)of_id->data;
>