Re: [PATCH] selftests/bpf: close the file descriptor to avoid resource leaks

On Fri, Apr 4, 2025 at 9:22 PM Andrii Nakryiko andrii.nakryiko@gmail.com wrote:

On Sun, Mar 23, 2025 at 11:43 PM Malaya Kumar Rout malayarout91@gmail.com wrote:

...

Static Analyis for bench_htab_mem.c with cppcheck:error tools/testing/selftests/bpf/benchs/bench_htab_mem.c:284:3: error: Resource leak: fd [resourceLeak] tools/testing/selftests/bpf/prog_tests/sk_assign.c:41:3: error: Resource leak: tc [resourceLeak]

fix the issue by closing the file descriptor (fd & tc) when read & fgets operation fails.

Signed-off-by: Malaya Kumar Rout malayarout91@gmail.com

tools/testing/selftests/bpf/benchs/bench_htab_mem.c | 1 + tools/testing/selftests/bpf/prog_tests/sk_assign.c | 4 +++- 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/benchs/bench_htab_mem.c b/tools/testing/selftests/bpf/benchs/bench_htab_mem.c index 926ee822143e..59746fd2c23a 100644 --- a/tools/testing/selftests/bpf/benchs/bench_htab_mem.c +++ b/tools/testing/selftests/bpf/benchs/bench_htab_mem.c @@ -281,6 +281,7 @@ static void htab_mem_read_mem_cgrp_file(const char *name, unsigned long *value) got = read(fd, buf, sizeof(buf) - 1);

It could be a bit cleaner to add close(fd) here and drop the one we have at the end of the function.

Here, close(fd) is now positioned within the error handling block, guaranteeing that the file descriptor will be closed prior to returning from the function in the event of a read error. Meanwhile, the final close(fd) at the end of the function is retained for successful execution, thereby avoiding any potential resource leaks. Hence, It is essential to add the close(fd) in both locations to prevent resource leakage.

pw-bot: cr

...

    if (got <= 0) {
            *value = 0;

•           close(fd);
            return;
    }
    buf[got] = 0;
  

diff --git a/tools/testing/selftests/bpf/prog_tests/sk_assign.c b/tools/testing/selftests/bpf/prog_tests/sk_assign.c index 0b9bd1d6f7cc..10a0ab954b8a 100644 --- a/tools/testing/selftests/bpf/prog_tests/sk_assign.c +++ b/tools/testing/selftests/bpf/prog_tests/sk_assign.c @@ -37,8 +37,10 @@ configure_stack(void) tc = popen("tc -V", "r"); if (CHECK_FAIL(!tc)) return false;

•   if (CHECK_FAIL(!fgets(tc_version, sizeof(tc_version), tc)))
  

•   if (CHECK_FAIL(!fgets(tc_version, sizeof(tc_version), tc))) {
  

•           pclose(tc);
  

this one looks good

...

            return false;

•   }
    if (strstr(tc_version, ", libbpf "))
            prog = "test_sk_assign_libbpf.bpf.o";
    else
  

-- 2.43.0