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| author | Su Hui <suhui@nfschina.com> | 2023-11-27 09:35:13 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-01-25 14:33:34 -0800 |
| commit | 6b08b1e6d85f67f5782a49daf4725dc281ed9be7 (patch) | |
| tree | 87d1843641166906441cf3707db94099bb04c066 | |
| parent | a9386c2f247611bfad7510b64eb2932e2c555a5a (diff) | |
| download | linux-stable-6b08b1e6d85f67f5782a49daf4725dc281ed9be7.tar.gz linux-stable-6b08b1e6d85f67f5782a49daf4725dc281ed9be7.tar.bz2 linux-stable-6b08b1e6d85f67f5782a49daf4725dc281ed9be7.zip | |
wifi: rtlwifi: rtl8821ae: phy: fix an undefined bitwise shift behavior
[ Upstream commit bc8263083af60e7e57c6120edbc1f75d6c909a35 ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -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 9ec62fff6f1a..a972afde40a7 100644 --- a/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c +++ b/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c @@ -51,9 +51,10 @@ 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);*/ |