mfd: mfd-core: Protect against NULL call-back function pointer (b195e101) · Commits · 戴 / test

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> Reviewed-by:

Mark Brown <broonie@kernel.org>

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);

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