linux-kernel - [BUG] power: supply: 88pm860x_battery: possible uninitialized-variable access in measure

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Message-ID: <e2080eb9-bbe2-5077-761d-b5594edb6006@gmail.com>
Date:   Wed, 28 Jul 2021 18:24:12 +0800
From:   Li Tuo <islituo@...il.com>
To:     sre@...nel.org
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        baijiaju1990@...il.com
Subject: [BUG] power: supply: 88pm860x_battery: possible
 uninitialized-variable access in measure_vbatt()

Hello,

Our static analysis tool finds a possible uninitialized-variable access 
in the 88pm860x_battery driver in Linux 5.14.0-rc3:

In calc_soc():
369:    int ocv;
376:    switch (state) {
380:    case OCV_MODE_SLEEP:
381:        ret = measure_vbatt(info, OCV_MODE_SLEEP, &ocv);

In measure_vbatt(struct pm860x_battery_info *info, int state, int *data)
176:    switch (state) {
184:    case OCV_MODE_SLEEP:
201:        *data = ((*data & 0xff) * 27 * 25) >> 9;

If the variable state is OCV_MODE_SLEEP, the function measure_vbatt() is 
called with the argument &ocv,
and the corresponding parameter is data. Thus *data is uninitialized but 
it is used at line 201.

I am not quite sure whether this possible uninitialized-variable access 
is real and how to fix it if it is real.
Any feedback would be appreciated, thanks!

Reported-by: TOTE Robot <oslab@...nghua.edu.cn>

Best wishes,
Tuo Li