linux-kernel - Re: [PATCH] pinctrl: core: Fix panic when pinctrl devices with hogs are unregistered

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Date:   Thu, 5 Jan 2017 11:27:48 -0800
From:   Tony Lindgren <tony@...mide.com>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     Jon Hunter <jonathanh@...dia.com>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>
Subject: Re: [PATCH] pinctrl: core: Fix panic when pinctrl devices with hogs
 are unregistered

* Linus Walleij <linus.walleij@...aro.org> [170105 08:16]:
> On Thu, Jan 5, 2017 at 4:52 PM, Jon Hunter <jonathanh@...dia.com> wrote:
> 
> > Commit df61b366af26 ('pinctrl: core: Use delayed work for hogs')
> > deferred part of the registration for pinctrl devices if the pinctrl
> > device has hogs. This introduced a window where if the pinctrl device
> > with hogs was sucessfully registered, but then unregistered again
> > (which could be caused by parent device being probe deferred) before
> > the delayed work has chanced to run, then this will cause a kernel
> > panic to occur because:
> >
> > 1. The 'pctldev->p' has not yet been initialised and when unregistering
> >    the pinctrl device we only check to see if it is an error value, but
> >    now it could also be NULL.
> > 2. The pinctrl device may not have been added to the 'pinctrldev_list'
> >    list and we don't check to see if it was added before removing.
> >
> > Fix up the above by checking to see if the 'pctldev->p' pointer is an
> > error value or NULL before putting the pinctrl device and verifying
> > that the pinctrl device is present in 'pinctrldev_list' before removing.
> >
> > Fixes: df61b366af26 ('pinctrl: core: Use delayed work for hogs')
> >
> > Signed-off-by: Jon Hunter <jonathanh@...dia.com>
> 
> Oops. Patch applied.

OK, did not see that with my testing of hogs with omap4-duovero-parlor.
Thanks for fixing that.

Tony