Re: [PATCH] pinctrl: protect pinctrl_list add

From: Stephen Warren
Date: Mon Feb 03 2014 - 16:13:00 EST


On 02/03/2014 04:39 AM, Stanislaw Gruszka wrote:
> We have few fedora bug reports about list corruption on pinctrl,
> for example:
> https://bugzilla.redhat.com/show_bug.cgi?id=1051918
>
> Most likely corruption happen due lack of protection of pinctrl_list
> when adding new nodes to it. Patch corrects that.
>
> Fixes: 57b676f9c1b ("pinctrl: fix and simplify locking")

After that patch ...

> diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c

> @@ -851,7 +851,9 @@ static struct pinctrl *create_pinctrl(struct device *dev)
> kref_init(&p->users);
>
> /* Add the pinctrl handle to the global list */
> + mutex_lock(&pinctrl_list_mutex);

That variable doesn't exist; it got replaced with the "global"
pinctrl_mutex. Also, since that patch, IIRC some other changes have been
made to the locking structure, so this patch might need adjustments not
to conflict with those changes?

> list_add_tail(&p->node, &pinctrl_list);
> + mutex_unlock(&pinctrl_list_mutex);

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