linux-kernel - Re: [PATCH v2 0/2] reset: rzg2l-usbphy-ctrl: Add suspend to RAM support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3d8896c7-9ba8-43f2-8464-a94acdf82ba3@tuxon.dev>
Date: Tue, 16 Dec 2025 11:03:54 +0200
From: Claudiu Beznea <claudiu.beznea@...on.dev>
To: Biju Das <biju.das.jz@...renesas.com>,
 "p.zabel@...gutronix.de" <p.zabel@...gutronix.de>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 "linux-renesas-soc@...r.kernel.org" <linux-renesas-soc@...r.kernel.org>,
 Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH v2 0/2] reset: rzg2l-usbphy-ctrl: Add suspend to RAM
 support

Hi, Biju,

On 12/7/25 13:02, Biju Das wrote:
> Hi Claudiu,
> 
>> -----Original Message-----
>> From: Claudiu Beznea <claudiu.beznea@...on.dev>
>> Sent: 05 December 2025 10:00
>> Subject: Re: [PATCH v2 0/2] reset: rzg2l-usbphy-ctrl: Add suspend to RAM support
>>
>> Hi, Biju,
>>
>> On 12/5/25 10:53, Biju Das wrote:
>>>
>>>
>>> Hi Claudiu,
>>>
>>>> -----Original Message-----
>>>> From: Claudiu Beznea <claudiu.beznea@...on.dev>
>>>> Sent: 04 December 2025 18:26
>>>> Subject: Re: [PATCH v2 0/2] reset: rzg2l-usbphy-ctrl: Add suspend to
>>>> RAM support
>>>>
>>>> Hi, Philipp,
>>>>
>>>> Could you please let me know if there's anything I should do for this series?
>>>
>>> If rzg2l_usbphy_ctrl_suspend() fails, What is the probability that it
>>> will suspend again without any issue
>>
>> How can I measure this?
>>
>> The idea with this code was the following: if any instruction of suspend fails, the suspend is
>> aborted, thus code in rzg2l_usbphy_ctrl_suspend() is trying to restore the runtime state of the HW so
>> that no runtime users of it to be affected. This is also how core suspend code is doing, e.g.
>> suspend_devices_and_enter().
> 
> After rechecking, the cleanup() in the suspend code making usage count unbalanced.
> 
> Eg:
>  Suspend returns error with the following usage count incremented 
> 
> static int rzg2l_usbphy_ctrl_suspend(struct device *dev)
> {
> reset_deassert:
> +	reset_control_deassert(priv->rstc);
> +rpm_resume:
> +	pm_runtime_resume_and_get(dev);
> +	return ret;
> }
> 
> 
> The suspend error code invokes device resume[1] and in that you are again calling
> reset_control_deassert() and pm_runtime_resume_and_get() which makes the usage
> count unbalanced forever.
> 
> So, looks like the current logic in the Add suspend to RAM support patch is wrong.

Seeing [1], [2], [3] being posted by you, and [2] following the same
pattern as proposed in this patch, are you still considering the approach
in this patch being wrong ?

Thank you,
Claudiu

[1]
https://lore.kernel.org/all/20251207124742.96526-1-biju.das.jz@bp.renesas.com
[2]
https://lore.kernel.org/all/20251208152133.269316-8-biju.das.jz@bp.renesas.com
[3]
https://lore.kernel.org/all/20251208101356.101379-1-biju.das.jz@bp.renesas.com