Re: [ovs-dev] [PATCH 4/4] general: Fix Clang's static analyzer 'Division by zero' warnings.

2023-10-18 Thread Eelco Chaudron 



On 18 Oct 2023, at 13:02, Simon Horman wrote:

> On Tue, Oct 17, 2023 at 03:49:55PM +0200, Eelco Chaudron wrote:
>
> Hi Eelco,
>
> As per my commoent on patch 3/4.
> I think it would be good to be clear about if these are bugs or not.

Dont think this will happen in real life, just to avoid clang warning. Will 
make this clear in the commit message.

Will send out a v2 next week to give other people time to react.

//Eelco

>> Signed-off-by: Eelco Chaudron 
>> ---
>>  lib/dpif-netdev.c   |4 
>>  tests/test-id-fpool.c   |2 +-
>>  tests/test-mpsc-queue.c |2 +-
>>  3 files changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
>> index 157694bcf..b8f065d1d 100644
>> --- a/lib/dpif-netdev.c
>> +++ b/lib/dpif-netdev.c
>> @@ -4748,6 +4748,10 @@ dpif_netdev_offload_stats_get(struct dpif *dpif,
>>  }
>>
>>  nb_thread = netdev_offload_thread_nb();
>> +if (!nb_thread) {
>> +return EINVAL;
>> +}
>> +
>>  /* nb_thread counters for the overall total as well. */
>>  stats->size = ARRAY_SIZE(hwol_stats) * (nb_thread + 1);
>>  stats->counters = xcalloc(stats->size, sizeof *stats->counters);
>> diff --git a/tests/test-id-fpool.c b/tests/test-id-fpool.c
>> index 27800aa9b..7bdb8154d 100644
>> --- a/tests/test-id-fpool.c
>> +++ b/tests/test-id-fpool.c
>> @@ -237,7 +237,7 @@ print_result(const char *prefix)
>>  for (i = 0; i < n_threads; i++) {
>>  avg += thread_working_ms[i];
>>  }
>> -avg /= n_threads;
>> +avg /= n_threads ? n_threads : 1;
>>  printf("%s: ", prefix);
>>  for (i = 0; i < n_threads; i++) {
>>  if (thread_working_ms[i] >= TIMEOUT_MS) {
>> diff --git a/tests/test-mpsc-queue.c b/tests/test-mpsc-queue.c
>> index 16aa804a0..86a223caf 100644
>> --- a/tests/test-mpsc-queue.c
>> +++ b/tests/test-mpsc-queue.c
>> @@ -315,7 +315,7 @@ print_result(const char *prefix, int reader_elapsed)
>>  for (i = 0; i < n_threads; i++) {
>>  avg += thread_working_ms[i];
>>  }
>> -avg /= n_threads;
>> +avg /= n_threads ? n_threads : 1;
>>  printf("%s:  %6d", prefix, reader_elapsed);
>>  for (i = 0; i < n_threads; i++) {
>>  printf(" %6" PRIu64, thread_working_ms[i]);
>>
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>> d...@openvswitch.org
>> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>>

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Re: [ovs-dev] [PATCH 4/4] general: Fix Clang's static analyzer 'Division by zero' warnings.

2023-10-18 Thread Simon Horman 
On Tue, Oct 17, 2023 at 03:49:55PM +0200, Eelco Chaudron wrote:

Hi Eelco,

As per my commoent on patch 3/4.
I think it would be good to be clear about if these are bugs or not.

> Signed-off-by: Eelco Chaudron 
> ---
>  lib/dpif-netdev.c   |4 
>  tests/test-id-fpool.c   |2 +-
>  tests/test-mpsc-queue.c |2 +-
>  3 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index 157694bcf..b8f065d1d 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -4748,6 +4748,10 @@ dpif_netdev_offload_stats_get(struct dpif *dpif,
>  }
>  
>  nb_thread = netdev_offload_thread_nb();
> +if (!nb_thread) {
> +return EINVAL;
> +}
> +
>  /* nb_thread counters for the overall total as well. */
>  stats->size = ARRAY_SIZE(hwol_stats) * (nb_thread + 1);
>  stats->counters = xcalloc(stats->size, sizeof *stats->counters);
> diff --git a/tests/test-id-fpool.c b/tests/test-id-fpool.c
> index 27800aa9b..7bdb8154d 100644
> --- a/tests/test-id-fpool.c
> +++ b/tests/test-id-fpool.c
> @@ -237,7 +237,7 @@ print_result(const char *prefix)
>  for (i = 0; i < n_threads; i++) {
>  avg += thread_working_ms[i];
>  }
> -avg /= n_threads;
> +avg /= n_threads ? n_threads : 1;
>  printf("%s: ", prefix);
>  for (i = 0; i < n_threads; i++) {
>  if (thread_working_ms[i] >= TIMEOUT_MS) {
> diff --git a/tests/test-mpsc-queue.c b/tests/test-mpsc-queue.c
> index 16aa804a0..86a223caf 100644
> --- a/tests/test-mpsc-queue.c
> +++ b/tests/test-mpsc-queue.c
> @@ -315,7 +315,7 @@ print_result(const char *prefix, int reader_elapsed)
>  for (i = 0; i < n_threads; i++) {
>  avg += thread_working_ms[i];
>  }
> -avg /= n_threads;
> +avg /= n_threads ? n_threads : 1;
>  printf("%s:  %6d", prefix, reader_elapsed);
>  for (i = 0; i < n_threads; i++) {
>  printf(" %6" PRIu64, thread_working_ms[i]);
> 
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> 
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[ovs-dev] [PATCH 4/4] general: Fix Clang's static analyzer 'Division by zero' warnings.

2023-10-17 Thread Eelco Chaudron 
Signed-off-by: Eelco Chaudron 
---
 lib/dpif-netdev.c   |4 
 tests/test-id-fpool.c   |2 +-
 tests/test-mpsc-queue.c |2 +-
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 157694bcf..b8f065d1d 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -4748,6 +4748,10 @@ dpif_netdev_offload_stats_get(struct dpif *dpif,
 }
 
 nb_thread = netdev_offload_thread_nb();
+if (!nb_thread) {
+return EINVAL;
+}
+
 /* nb_thread counters for the overall total as well. */
 stats->size = ARRAY_SIZE(hwol_stats) * (nb_thread + 1);
 stats->counters = xcalloc(stats->size, sizeof *stats->counters);
diff --git a/tests/test-id-fpool.c b/tests/test-id-fpool.c
index 27800aa9b..7bdb8154d 100644
--- a/tests/test-id-fpool.c
+++ b/tests/test-id-fpool.c
@@ -237,7 +237,7 @@ print_result(const char *prefix)
 for (i = 0; i < n_threads; i++) {
 avg += thread_working_ms[i];
 }
-avg /= n_threads;
+avg /= n_threads ? n_threads : 1;
 printf("%s: ", prefix);
 for (i = 0; i < n_threads; i++) {
 if (thread_working_ms[i] >= TIMEOUT_MS) {
diff --git a/tests/test-mpsc-queue.c b/tests/test-mpsc-queue.c
index 16aa804a0..86a223caf 100644
--- a/tests/test-mpsc-queue.c
+++ b/tests/test-mpsc-queue.c
@@ -315,7 +315,7 @@ print_result(const char *prefix, int reader_elapsed)
 for (i = 0; i < n_threads; i++) {
 avg += thread_working_ms[i];
 }
-avg /= n_threads;
+avg /= n_threads ? n_threads : 1;
 printf("%s:  %6d", prefix, reader_elapsed);
 for (i = 0; i < n_threads; i++) {
 printf(" %6" PRIu64, thread_working_ms[i]);

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