> On Oct 31, 2020, at 4:27 AM, David Laight <david.lai...@aculab.com> wrote:
>
> From: Song Liu
>> Sent: 30 October 2020 23:55
>>
>> Making perf with gcc-9.1.1 generates the following warning:
>>
>> CC ui/browsers/hists.o
>> ui/browsers/hists.c: In function 'perf_evsel__hists_browse':
>> ui/browsers/hists.c:3078:61: error: '%d' directive output may be \
>> truncated writing between 1 and 11 bytes into a region of size \
>> between 2 and 12 [-Werror=format-truncation=]
>>
>> 3078 | "Max event group index to sort is %d (index from 0 to %d)",
>> | ^~
>> ui/browsers/hists.c:3078:7: note: directive argument in the range
>> [-2147483648, 8]
>> 3078 | "Max event group index to sort is %d (index from 0 to %d)",
>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> In file included from /usr/include/stdio.h:937,
>> from ui/browsers/hists.c:5:
>>
>> IOW, the string in line 3078 might be too long for buf[] of 64 bytes.
>>
>> Fix this by increasing the size of buf[] to 128.
>
> ISTM that something should be unsigned so that the bound check
> that puts an upper bound of 8 implies a lower bound.
>
> David
Changing both "%d" in this line to "%u" does fix the warning. But we
are printing "evsel->core.nr_members - 1" here, and nr_members is
signed int. So I feel more comfortable keep the "%d"s and increase
the buffer size.
Thanks,
Song
