On 8/14/25 8:32 AM, Krzysztof Kozlowski wrote:
> The ISR calls dev_pm_opp_find_bw_ceil(), which can return EINVAL, ERANGE
> or ENODEV, and if that one fails with ERANGE, then it tries again with
> floor dev_pm_opp_find_bw_floor().
>
> Code misses error checks for two cases:
> 1. First dev_pm_opp_find_bw_ceil() failed with error different than
> ERANGE,
> 2. Any error from second dev_pm_opp_find_bw_floor().
>
> In an unlikely case these error happened, the code would further
> dereference the ERR pointer. Close that possibility and make the code
> more obvious that all errors are correctly handled.
>
> Reported by Smatch:
> icc-bwmon.c:693 bwmon_intr_thread() error: 'target_opp' dereferencing possible ERR_PTR()
>
> Fixes: b9c2ae6cac40 ("soc: qcom: icc-bwmon: Add bandwidth monitoring driver")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Closes: https://lore.kernel.org/r/aJTNEQsRFjrFknG9@stanley.mountain/
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
>
> ---
>
> Some unreleased smatch, though, because I cannot reproduce the warning,
> but I imagine Dan keeps the tastiests reports for later. :)
> ---
> drivers/soc/qcom/icc-bwmon.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/soc/qcom/icc-bwmon.c b/drivers/soc/qcom/icc-bwmon.c
> index 3dfa448bf8cf..597f9025e422 100644
> --- a/drivers/soc/qcom/icc-bwmon.c
> +++ b/drivers/soc/qcom/icc-bwmon.c
> @@ -656,6 +656,9 @@ static irqreturn_t bwmon_intr_thread(int irq, void *dev_id)
> if (IS_ERR(target_opp) && PTR_ERR(target_opp) == -ERANGE)
> target_opp = dev_pm_opp_find_bw_floor(bwmon->dev, &bw_kbps, 0);
>
> + if (IS_ERR(target_opp))
> + return IRQ_HANDLED;
So the thunk above checks for a ceil freq relative to bw_kbps and then
if it doesn't exist, for a floor one
Meaning essentially if we fall into this branch, there's no OPPs in the
table, which would have been caught in probe
Konrad
