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authorLee Jones <lee.jones@linaro.org>2019-10-21 12:16:34 +0300
committerLee Jones <lee.jones@linaro.org>2019-11-11 11:45:03 +0300
commitb195e101580db390f50b0d587b7f66f241d2bc88 (patch)
tree35f5a044a7379036a0bd9dce890bad2125176620 /drivers/mfd/mfd-core.c
parent99cd1059759833f83cc7e442fe2c3b0bd4dff399 (diff)
downloadlinux-b195e101580db390f50b0d587b7f66f241d2bc88.tar.xz
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: Lee Jones <lee.jones@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/mfd/mfd-core.c')
-rw-r--r--drivers/mfd/mfd-core.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index 23276a80e3b4..96d02b6f06fd 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->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);