On Wednesday, January 15, 2025 10:57 PM, Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote:
>On 1/14/25 4:27 PM, Song Yoong Siang wrote:
>[...]
>> + /* Add mqprio qdisc with TC and hardware queue one-to-one mapping */
>> + char map[256] = {0};
>> + char queues[256] = {0};
>> +
>> + for (i = 0; i < rxq; i++) {
>> + char buf[8];
>> +
>> + snprintf(buf, sizeof(buf), "%d ", i);
>> + strcat(map, buf);
>> +
>> + snprintf(buf, sizeof(buf), "1@%d ", i);
>> + strcat(queues, buf);
>> + }
>> + run_command("sudo tc qdisc add dev %s handle 8001: parent root mqprio
>num_tc %d map %s queues %s hw 0",
>> + ifname, rxq, map, queues);
>
>Fyi, above triggers selftest build errors:
>
> xdp_hw_metadata.c: In function ‘main’:
> xdp_hw_metadata.c:763:45: error: ‘%d’ directive output may be truncated
>writing between 1 and 10 bytes into a region of size 8 [-Werror=format-
>truncation=]
> 763 | snprintf(buf, sizeof(buf), "%d ", i);
> | ^~
> TEST-OBJ [test_progs] arg_parsing.test.o
> xdp_hw_metadata.c:763:44: note: directive argument in the range [0,
>2147483646]
> 763 | snprintf(buf, sizeof(buf), "%d ", i);
> | ^~~~~
> xdp_hw_metadata.c:763:17: note: ‘snprintf’ output between 3 and 12 bytes into
>a destination of size 8
> 763 | snprintf(buf, sizeof(buf), "%d ", i);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> xdp_hw_metadata.c:766:47: error: ‘%d’ directive output may be truncated
>writing between 1 and 10 bytes into a region of size 6 [-Werror=format-
>truncation=]
> 766 | snprintf(buf, sizeof(buf), "1@%d ", i);
> | ^~
> xdp_hw_metadata.c:766:44: note: directive argument in the range [0,
>2147483646]
> 766 | snprintf(buf, sizeof(buf), "1@%d ", i);
> | ^~~~~~~
> xdp_hw_metadata.c:766:17: note: ‘snprintf’ output between 5 and 14 bytes into
>a destination of size 8
> 766 | snprintf(buf, sizeof(buf), "1@%d ", i);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Thanks for pointing this out.
Btw, do you know which build command will trigger these errors?
I am using "make -C tools/testing/selftests/bpf" but cannot
reproduce the build error.
Thanks & Regards
Siang
