Commit 709bbb01 authored by David Yang's avatar David Yang Committed by Jakub Kicinski
Browse files

net: dsa: yt921x: Fix MIB overflow wraparound routine 



Reported by the following Smatch static checker warning:

  drivers/net/dsa/yt921x.c:702 yt921x_read_mib()
  warn: was expecting a 64 bit value instead of '(~0)'

Fixes: 186623f4 ("net: dsa: yt921x: Add support for Motorcomm YT921x")
Reported-by: default avatarDan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/netdev/aPsjYKQMzpY0nSXm@stanley.mountain/


Suggested-by: default avatarDavid Laight <david.laight.linux@gmail.com>
Signed-off-by: default avatarDavid Yang <mmyangfl@gmail.com>
Link: https://patch.msgid.link/20260122170512.2713738-1-mmyangfl@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent ca12c4a1

drivers/net/dsa/yt921x.c

+8 −7
Original line number Diff line number Diff line
@@ -682,21 +682,22 @@ static int yt921x_read_mib(struct yt921x_priv *priv, int port) 
		const struct yt921x_mib_desc *desc = &yt921x_mib_descs[i];

		u32 reg = YT921X_MIBn_DATA0(port) + desc->offset;

		u64 *valp = &((u64 *)mib)[i];

		u64 val = *valp;

		u32 val0;

		u32 val1;

		u64 val;



		res = yt921x_reg_read(priv, reg, &val0);

		if (res)

			break;



		if (desc->size <= 1) {

			if (val < (u32)val)

				/* overflow */

				val += (u64)U32_MAX + 1;

			val &= ~U32_MAX;

			val |= val0;

			u64 old_val = *valp;



			val = (old_val & ~(u64)U32_MAX) | val0;

			if (val < old_val)

				val += 1ull << 32;

		} else {

			u32 val1;



			res = yt921x_reg_read(priv, reg + 4, &val1);

			if (res)

				break;