Commit b195e101 authored by Lee Jones's avatar Lee Jones
Browse files

mfd: mfd-core: Protect against NULL call-back function pointer 



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: default avatarLee Jones <lee.jones@linaro.org>
Reviewed-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: default avatarMark Brown <broonie@kernel.org>
parent 99cd1059

drivers/mfd/mfd-core.c

+10 −0
Original line number Diff line number Diff line
@@ -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->disable) {

		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);