On 02/05/2019 06:12 PM, Breno Leitao wrote: > When compiling test_maps selftest with GCC-8, it warns that an array might > be indexed with a negative value, which could cause a negative out of bound > access, depending on parameters of the function. This is the GCC-8 warning: > > gcc -Wall -O2 -I../../../include/uapi -I../../../lib -I../../../lib/bpf > -I../../../../include/generated -DHAVE_GENHDR -I../../../include > test_maps.c /home/breno/Devel/linux/tools/testing/selftests/bpf/libbpf.a > -lcap -lelf -lrt -lpthread -o > /home/breno/Devel/linux/tools/testing/selftests/bpf/test_maps > In file included from test_maps.c:16: > test_maps.c: In function ‘run_all_tests’: > test_maps.c:1079:10: warning: array subscript -1 is below array bounds > of ‘pid_t[<Ube20> + 1]’ [-Warray-bounds] > assert(waitpid(pid[i], &status, 0) == pid[i]); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~ > test_maps.c:1059:6: warning: array subscript -1 is below array bounds > of ‘pid_t[<Ube20> + 1]’ [-Warray-bounds] > pid[i] = fork(); > ~~~^~~ > > This patch simply guarantees that the task(s) variables are unsigned, thus, > they could never be a negative number, hence avoiding an out of bound access > warning. > > Signed-off-by: Breno Leitao <lei...@debian.org>
Given this is a false positive anyway and we only want to reduce gcc noise, I've applied it to bpf-next, thanks Breno!
