linux-kernel - Re: [PATCH] mfd: syscon: Don't free allocated name for regmap

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Date:   Fri, 25 Sep 2020 19:28:30 -0500
From:   Suman Anna <s-anna@...com>
To:     Lee Jones <lee.jones@...aro.org>, Marc Zyngier <maz@...nel.org>
CC:     <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        Arnd Bergmann <arnd@...db.de>, <kernel-team@...roid.com>
Subject: Re: [PATCH] mfd: syscon: Don't free allocated name for regmap_config

On 9/24/20 7:39 AM, Lee Jones wrote:
> On Thu, 03 Sep 2020, Marc Zyngier wrote:
> 
>> The name allocated for the regmap_config structure is freed
>> pretty early, right after the registration of the MMIO region.
>>
>> Unfortunately, that doesn't follow the life cycle that debugfs
>> expects, as it can access the name field long after the free
>> has occured.
>>
>> Move the free on the error path, and keep it forever otherwise.
>>
>> Fixes: e15d7f2b81d2 ("mfd: syscon: Use a unique name with regmap_config")
>> Signed-off-by: Marc Zyngier <maz@...nel.org>
>> ---
>>  drivers/mfd/syscon.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Fixed the spelling mistake and applied, thanks.
> 

Marc,
Can you recheck the behavior once on the latest master to see if this patch is
still needed? I see a new patch within the regmap core that is dealing with the
delayed debugfs registration name. This follows the similar design logic I
suggested on your initial submission [1].

Please see commit 94cc89eb8fa5 ("regmap: debugfs: Fix handling of name string
for debugfs init delays") in mainline.

Lee,
I haven't seen this patch in -next yet, so maybe worthwhile to hold it a little
longer.

regards
Suman

[1] https://patchwork.kernel.org/comment/23575471/