diff options
| author | David Yang <mmyangfl@gmail.com> | 2026-01-23 01:05:09 +0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-01-25 15:16:01 -0800 |
| commit | 709bbb015538dfd5c97308b77c950d41a4d95cd3 (patch) | |
| tree | eec0203eef7d2b3fc825426b5f5627bf6e6bc043 | |
| parent | ca12c4a155ebf84e9ef29b05ce979bc89364290f (diff) | |
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: 186623f4aa72 ("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>
| -rw-r--r-- | drivers/net/dsa/yt921x.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/drivers/net/dsa/yt921x.c b/drivers/net/dsa/yt921x.c index 1c511f5dc6ab..7b8c1549a0fb 100644 --- a/drivers/net/dsa/yt921x.c +++ b/drivers/net/dsa/yt921x.c @@ -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; |