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SubjectRe: [PATCH v1] mfd: core: Fix double-free in mfd_remove_devices_fn()
On Mon, 24 Aug 2020, Marek Szyprowski wrote:

> Hi
>
> On 18.08.2020 01:50, Dmitry Osipenko wrote:
> > The pdev.mfd_cell is released by platform_device_release(), which is
> > invoked by platform_device_unregister(). Hence mfd_remove_devices_fn()
> > shouldn't release the cell variable. The double-free bug is reported KASAN
> > during of MFD driver module removal.
> >
> > Fixes: 466a62d7642f ("mfd: core: Make a best effort attempt to match devices with the correct of_nodes")
> > Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> > ---
>
> I've reported that almost a week earlier and got information that it
> will be dropped:
>
> https://lore.kernel.org/lkml/79bcd1b5-2247-5e00-7d49-2f94f9b40744@samsung.com/
>
> https://lore.kernel.org/lkml/20200813080100.GI4354@dell/
>
> Sadly it finally landed in v5.9-rc1. Would be nice to mention this in
> the revert:

That's true. The patch was taken out but the change managed to get in
via another commit. I will add your Reported-by to the revert.

> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
>
> > drivers/mfd/mfd-core.c | 2 --
> > 1 file changed, 2 deletions(-)
> >
> > diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
> > index c3651f06684f..c50718e3db58 100644
> > --- a/drivers/mfd/mfd-core.c
> > +++ b/drivers/mfd/mfd-core.c
> > @@ -370,8 +370,6 @@ static int mfd_remove_devices_fn(struct device *dev, void *data)
> > regulator_bulk_unregister_supply_alias(dev, cell->parent_supplies,
> > cell->num_parent_supplies);
> >
> > - kfree(cell);
> > -
> > platform_device_unregister(pdev);
> > return 0;
> > }
>
> Best regards

--
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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