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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: 186623f4aa ("net: dsa: yt921x: Add support for Motorcomm YT921x")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/netdev/aPsjYKQMzpY0nSXm@stanley.mountain/
Suggested-by: David Laight <david.laight.linux@gmail.com>
Signed-off-by: David Yang <mmyangfl@gmail.com>
Link: https://patch.msgid.link/20260122170512.2713738-1-mmyangfl@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
master
David Yang 2026-01-23 01:05:09 +08:00 committed by Jakub Kicinski
parent ca12c4a155
commit 709bbb0155
1 changed files with 8 additions and 7 deletions
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15
drivers/net/dsa/yt921x.c
View File

@ -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;