linux-kernel - Re: [PATCH 4/4] pinctrl: re-enable old state in case of error in pinctrl_select

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: <CACQ1gAjZjcBzW5dEBYL3LzbkCq+Bj1g3jCGk1o8OMsZ9T8RH2w@mail.gmail.com>
Date:	Thu, 28 Mar 2013 12:35:04 +0100
From:	Richard Genoud <richard.genoud@...il.com>
To:	Stephen Warren <swarren@...dotorg.org>
Cc:	Linus Walleij <linus.walleij@...aro.org>,
	Stephen Warren <swarren@...dia.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/4] pinctrl: re-enable old state in case of error in pinctrl_select_state

2013/3/28 Stephen Warren <swarren@...dotorg.org>:
> On 03/25/2013 08:47 AM, Richard Genoud wrote:
>> If a new state is applied, the groups configured in the old state but
>> not in the new state are disabled.
>> If something goes wrong and the new state can't be applied, we have to
>> re-enable those groups.
>
> What is the use-case for this? I wonder if it isn't better to simply
> undo the partial selection of the new state (as patch 3/4 attempts to
> do) and then leave p->state==NULL, indicating that no state is actively
> selected. IIRC, this would be the same as right after the initial
> pinctrl_select().
>
> I wonder if it's likely that attempting to re-apply the old state would
> actually work, given that applying something just failed.
>
> Finally, this recovery code doesn't:
>
> a) Process anything except MUX_GROUP; any pin config settings in the old
> state aren't restored.
>
> b) (I think) Apply any mux settings that don't involve groups that are
> referenced by both the old and new states; given that patch 3/4 attempts
> to undo everything in the failed application of the new state, I think
> this "re-apply the old state" code should simple run through everything
> in the old state any apply it unconditionally.
Well, I'm not comfortable enough with this code to argue on that...

> c) Set p->state = oldstate, so it's left at NULL, which would confuse
> any future pinctrl_select().
Arrrggg !
I forgot it !
I'll send a fix on that


-- 
for me, ck means con kolivas and not calvin klein... does it mean I'm a geek ?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/