linux-kernel - Re: [PATCH v1 RESEND] spmi: hisi-spmi-controller: Fix kernel panic on rmmod

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Date: Mon, 29 Jan 2024 10:13:22 +0530
From: VAMSHI GAJJELA <vamshigajjela@...gle.com>
To: Johan Hovold <johan@...nel.org>
Cc: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>, Stephen Boyd <sboyd@...nel.org>, 
	Johan Hovold <johan+linaro@...nel.org>, Caleb Connolly <caleb.connolly@...aro.org>, 
	linux-kernel@...r.kernel.org, manugautam@...gle.com
Subject: Re: [PATCH v1 RESEND] spmi: hisi-spmi-controller: Fix kernel panic on rmmod

On Fri, Jan 26, 2024 at 1:48 PM Johan Hovold <johan@...nel.org> wrote:
>
> On Fri, Jan 26, 2024 at 11:41:53AM +0530, Vamshi Gajjela wrote:
> > Ensure consistency in spmi_controller pointers between
> > spmi_controller_remove/put and driver spmi_del_controller functions.
> > The former requires a pointer to struct spmi_controller, while the
> > latter passes a pointer of struct spmi_controller_dev, leading to a
> > "Null pointer exception".
> >
> > 'nr' member of struct spmi_controller, which serves as an identifier
> > for the controller/bus. This value is assigned a dynamic ID in
> > spmi_controller_alloc, and overriding it from the driver results in an
> > ida_free error "ida_free called for id=xx which is not allocated".
>
> No Fixes tag?
There isn't a bug, I will remove word "Fix"
>
> > Signed-off-by: Vamshi Gajjela <vamshigajjela@...gle.com>
> > ---
> >  drivers/spmi/hisi-spmi-controller.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/spmi/hisi-spmi-controller.c b/drivers/spmi/hisi-spmi-controller.c
> > index 9cbd473487cb..af51ffe24072 100644
> > --- a/drivers/spmi/hisi-spmi-controller.c
> > +++ b/drivers/spmi/hisi-spmi-controller.c
> > @@ -303,7 +303,6 @@ static int spmi_controller_probe(struct platform_device *pdev)
> >
> >       spin_lock_init(&spmi_controller->lock);
> >
> > -     ctrl->nr = spmi_controller->channel;
This remains applicable, however, it could lead to a failure in the
spmi_ctrl_release, I
will refactor the patch to address this.
also "spmi_del_controller" is removed from 6.7.2
> >       ctrl->dev.parent = pdev->dev.parent;
> >       ctrl->dev.of_node = of_node_get(pdev->dev.of_node);
> >
> > @@ -326,7 +325,8 @@ static int spmi_controller_probe(struct platform_device *pdev)
> >
> >  static void spmi_del_controller(struct platform_device *pdev)
>
> This function does not exist in mainline so presumably this is some bug
> you've introduced in your downstream driver that you're trying to fix.
>
> So this patch looks all bogus.
spmi_del_controller is present until in 6.7.2, I have made this patch
in last week of Dec,
I should have checked before resending, apologies.


>
> >  {
> > -     struct spmi_controller *ctrl = platform_get_drvdata(pdev);
> > +     struct spmi_controller_dev *spmi_controller = platform_get_drvdata(pdev);
> > +     struct spmi_controller *ctrl = spmi_controller->controller;
> >
> >       spmi_controller_remove(ctrl);
> >       spmi_controller_put(ctrl);
>
> Johan