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| author | Su Hui <suhui@nfschina.com> | 2023-11-27 04:35:13 +0300 |
|---|---|---|
| committer | Kalle Valo <kvalo@kernel.org> | 2023-11-30 22:22:06 +0300 |
| commit | bc8263083af60e7e57c6120edbc1f75d6c909a35 (patch) | |
| tree | 766b7c7513ae67c010a0e33e1547c639dc69a1e7 /drivers/net/wireless/realtek/rtlwifi | |
| parent | cda37445718d917c22fe1f2cf7ab1f501e6f84b2 (diff) | |
| download | linux-bc8263083af60e7e57c6120edbc1f75d6c909a35.tar.xz | |
wifi: rtlwifi: rtl8821ae: phy: fix an undefined bitwise shift behavior
Clang static checker warns:
drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c:184:49:
The result of the left shift is undefined due to shifting by '32',
which is greater or equal to the width of type 'u32'.
[core.UndefinedBinaryOperatorResult]
If the value of the right operand is negative or is greater than or
equal to the width of the promoted left operand, the behavior is
undefined.[1][2]
For example, when using different gcc's compilation optimization options
(-O0 or -O2), the result of '(u32)data << 32' is different. One is 0, the
other is old value of data. Let _rtl8821ae_phy_calculate_bit_shift()'s
return value less than 32 to fix this problem. Warn if bitmask is zero.
[1] https://stackoverflow.com/questions/11270492/what-does-the-c-standard-say-about-bitshifting-more-bits-than-the-width-of-type
[2] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf
Fixes: 21e4b0726dc6 ("rtlwifi: rtl8821ae: Move driver from staging to regular tree")
Signed-off-by: Su Hui <suhui@nfschina.com>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231127013511.26694-2-suhui@nfschina.com
Diffstat (limited to 'drivers/net/wireless/realtek/rtlwifi')
| -rw-r--r-- | drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c b/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c index 6df270e29e66..68c3fb0395ce 100644 --- a/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c +++ b/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c @@ -29,9 +29,10 @@ static void _rtl8821ae_phy_rf_serial_write(struct ieee80211_hw *hw, u32 data); static u32 _rtl8821ae_phy_calculate_bit_shift(u32 bitmask) { - u32 i = ffs(bitmask); + if (WARN_ON_ONCE(!bitmask)) + return 0; - return i ? i - 1 : 32; + return __ffs(bitmask); } static bool _rtl8821ae_phy_bb8821a_config_parafile(struct ieee80211_hw *hw); /*static bool _rtl8812ae_phy_config_mac_with_headerfile(struct ieee80211_hw *hw);*/ |