Hi,

On 02/12/2018 03:59 PM, Viresh Kumar wrote:

On 12-02-18, 15:51, Shilpasri G Bhat wrote:

quoted

This patch fixes the below Coverity warning:

*** CID 182816:  Memory - illegal accesses  (NEGATIVE_RETURNS)
/drivers/cpufreq/powernv-cpufreq.c: 1008 in powernv_fast_switch()
1002     					unsigned int target_freq)
1003     {
1004     	int index;
1005     	struct powernv_smp_call_data freq_data;
1006
1007     	index = cpufreq_table_find_index_dl(policy, target_freq);

quoted

quoted

quoted

    CID 182816:  Memory - illegal accesses  (NEGATIVE_RETURNS)
    Using variable "index" as an index to array "powernv_freqs".

1008     	freq_data.pstate_id = powernv_freqs[index].driver_data;
1009     	freq_data.gpstate_id = powernv_freqs[index].driver_data;
1010     	set_pstate(&freq_data);
1011
1012     	return powernv_freqs[index].frequency;
1013     }

Signed-off-by: Shilpasri G Bhat <redacted>
---
 drivers/cpufreq/powernv-cpufreq.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index 29cdec1..69edfe9 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c

@@ -1005,6 +1005,9 @@ static unsigned int powernv_fast_switch(struct cpufreq_policy *policy,
 	struct powernv_smp_call_data freq_data;
 
 	index = cpufreq_table_find_index_dl(policy, target_freq);
+	if (unlikely(index < 0))
+		index = get_nominal_index();
+

AFAICT, you will get -1 here only if the freq table had no valid
frequencies (or the freq table is empty). Why would that happen ?

I agree too. There is no way we can get -1 with initialized cpu frequency table.
We don't initialize powernv-cpufreq if we don't have valid CPU frequency
entries. Is there any other way to suppress the Coverity tool warning apart from
ignoring it?

Thanks and Regards,
Shilpa

quoted

 	freq_data.pstate_id = powernv_freqs[index].driver_data;
 	freq_data.gpstate_id = powernv_freqs[index].driver_data;
 	set_pstate(&freq_data);
-- 
1.8.3.1