Messages in this thread | | | Date | Mon, 21 Oct 2019 13:30:12 +0100 | From | Daniel Thompson <> | Subject | Re: [PATCH v2 7/9] mfd: mfd-core: Protect against NULL call-back function pointer |
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On Mon, Oct 21, 2019 at 11:58:20AM +0100, Lee Jones wrote: > If a child device calls mfd_cell_{en,dis}able() without an appropriate > call-back being set, we are likely to encounter a panic. Avoid this > by adding suitable checking. > > Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
> --- > drivers/mfd/mfd-core.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c > index 8126665bb2d8..90b43b44a15a 100644 > --- a/drivers/mfd/mfd-core.c > +++ b/drivers/mfd/mfd-core.c > @@ -28,6 +28,11 @@ int mfd_cell_enable(struct platform_device *pdev) > const struct mfd_cell *cell = mfd_get_cell(pdev); > int err = 0; > > + if (!cell->enable) { > + dev_dbg(&pdev->dev, "No .enable() call-back registered\n"); > + return 0; > + } > + > /* only call enable hook if the cell wasn't previously enabled */ > if (atomic_inc_return(cell->usage_count) == 1) > err = cell->enable(pdev); > @@ -45,6 +50,11 @@ int mfd_cell_disable(struct platform_device *pdev) > const struct mfd_cell *cell = mfd_get_cell(pdev); > int err = 0; > > + if (!cell->enable) { > + dev_dbg(&pdev->dev, "No .disable() call-back registered\n"); > + return 0; > + } > + > /* only disable if no other clients are using it */ > if (atomic_dec_return(cell->usage_count) == 0) > err = cell->disable(pdev); > -- > 2.17.1 >
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