Commit 8dec3131 authored by Lee Jones's avatar Lee Jones Committed by Greg Kroah-Hartman

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

[ Upstream commit b195e101 ]

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>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent a8fedff3
......@@ -32,6 +32,11 @@ 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);
......@@ -49,6 +54,11 @@ 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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