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From:   Inigo Huguet <ihuguet@redhat.com>
Date:   Fri, 23 Apr 2021 14:56:47 +0200
Message-ID: <CACT4ouecdXk3SQrgUNKnr4u2WAaiBUjgou5u_H1bEubTcrGtFQ@mail.gmail.com>
Subject: rtlwifi: potential bugs
To:     pkshih@realtek.com, linux-wireless@vger.kernel.org
Cc:     Ivan Vecera <ivecera@redhat.com>
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Hello,

Executing some static analysis on the kernel, we've got this results
affecting rtlwifi drivers:

Error: IDENTICAL_BRANCHES (CWE-398): [#def212]
kernel-5.11.0-0.rc7.151/linux-5.11.0-0.rc7.151.el9.x86_64/drivers/net/wirel=
ess/realtek/rtlwifi/btcoexist/halbtc8821a2ant.c:2813:
identical_branches: The same code is executed regardless of whether
"bt_rssi_state =3D=3D BTC_RSSI_STATE_HIGH || bt_rssi_state =3D=3D
BTC_RSSI_STATE_STAY_HIGH" is true, because the 'then' and 'else'
branches are identical. Should one of the branches be modified, or the
entire 'if' statement replaced?
# 2811|   }
# 2812|
# 2813|-> if ((bt_rssi_state =3D=3D BTC_RSSI_STATE_HIGH) ||
# 2814|      (bt_rssi_state =3D=3D BTC_RSSI_STATE_STAY_HIGH)) {
# 2815|   btc8821a2ant_ps_tdma(btcoexist, NORMAL_EXEC, true, 23);

Error: IDENTICAL_BRANCHES (CWE-398): [#def213]
kernel-5.11.0-0.rc7.151/linux-5.11.0-0.rc7.151.el9.x86_64/drivers/net/wirel=
ess/realtek/rtlwifi/btcoexist/halbtc8821a2ant.c:2947:
identical_branches: The same code is executed regardless of whether
"bt_rssi_state =3D=3D BTC_RSSI_STATE_HIGH || bt_rssi_state =3D=3D
BTC_RSSI_STATE_STAY_HIGH" is true, because the 'then' and 'else'
branches are identical. Should one of the branches be modified, or the
entire 'if' statement replaced?
# 2945|   }
# 2946|
# 2947|-> if ((bt_rssi_state =3D=3D BTC_RSSI_STATE_HIGH) ||
# 2948|      (bt_rssi_state =3D=3D BTC_RSSI_STATE_STAY_HIGH))
# 2949|   btc8821a2ant_ps_tdma(btcoexist, NORMAL_EXEC, true, 26);

Error: IDENTICAL_BRANCHES (CWE-398): [#def214]
kernel-5.11.0-0.rc7.151/linux-5.11.0-0.rc7.151.el9.x86_64/drivers/net/wirel=
ess/realtek/rtlwifi/btcoexist/halbtc8821a2ant.c:3135:
identical_branches: The same code is executed regardless of whether
"wifi_bw =3D=3D BTC_WIFI_BW_LEGACY" is true, because the 'then' and 'else'
branches are identical. Should one of the branches be modified, or the
entire 'if' statement replaced?
# 3133|   btcoexist->btc_get(btcoexist, BTC_GET_U4_WIFI_BW, &wifi_bw);
# 3134|
# 3135|-> if (wifi_bw =3D=3D BTC_WIFI_BW_LEGACY) {
# 3136|   /* for HID at 11b/g mode */
# 3137|   btc8821a2ant_coex_table(btcoexist, NORMAL_EXEC, 0x55ff55ff,

Error: IDENTICAL_BRANCHES (CWE-398): [#def215]
kernel-5.11.0-0.rc7.151/linux-5.11.0-0.rc7.151.el9.x86_64/drivers/net/wirel=
ess/realtek/rtlwifi/btcoexist/halbtc8821a2ant.c:3324:
identical_branches: The same code is executed regardless of whether
"bt_rssi_state =3D=3D BTC_RSSI_STATE_HIGH || bt_rssi_state =3D=3D
BTC_RSSI_STATE_STAY_HIGH" is true, because the 'then' and 'else'
branches are identical. Should one of the branches be modified, or the
entire 'if' statement replaced?
# 3322|   }
# 3323|
# 3324|-> if ((bt_rssi_state =3D=3D BTC_RSSI_STATE_HIGH) ||
# 3325|      (bt_rssi_state =3D=3D BTC_RSSI_STATE_STAY_HIGH)) {
# 3326|   btc8821a2ant_ps_tdma(btcoexist, NORMAL_EXEC, true, 23);


In my opinion, they seem to be real bugs. However, it's very difficult
to imagine what actions must be taken on each branch of the if-else
because they strongly depend on magic numbers, which are different
configurations for the hw, I guess.

Can the maintainers confirm if these are real bugs and see how to fix them?

Regards
--=20
=C3=8D=C3=B1igo Huguet