[PATCH] power: supply: axp20x_ac_power: Annotate struct axp20x_ac_power with __counted_by

[Kees Cook]

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct axp20x_ac_power.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Sebastian Reichel <sre@xxxxxxxxxx>
Cc: Chen-Yu Tsai <wens@xxxxxxxx>
Cc: linux-pm@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 drivers/power/supply/axp20x_ac_power.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/power/supply/axp20x_ac_power.c b/drivers/power/supply/axp20x_ac_power.c
index 19a118633115..e5733cb9e19e 100644
--- a/drivers/power/supply/axp20x_ac_power.c
+++ b/drivers/power/supply/axp20x_ac_power.c
@@ -45,7 +45,7 @@ struct axp20x_ac_power {
 	struct iio_channel *acin_i;
 	bool has_acin_path_sel;
 	unsigned int num_irqs;
-	unsigned int irqs[];
+	unsigned int irqs[] __counted_by(num_irqs);
 };
 
 static irqreturn_t axp20x_ac_power_irq(int irq, void *devid)
-- 
2.34.1