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selftests/bpf: Add a kprobe_multi subtest to use addrs instead of syms

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Get addrs directly from available_filter_functions_addrs and
send to the kernel during kprobe_multi_attach. This avoids
consultation of /proc/kallsyms. But available_filter_functions_addrs
is introduced in 6.5, i.e., it is introduced recently,
so I skip the test if the kernel does not support it.

Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240326041523.1200301-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Yonghong Song 2024-03-25 21:15:23 -07:00 committed by Alexei Starovoitov
parent 9edaafadc2
commit 6302bdeb91
1 changed files with 98 additions and 0 deletions
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98
tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
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@ -477,6 +477,69 @@ error:
return err;
}
static int get_addrs(unsigned long **addrsp, size_t *cntp, bool kernel)
{
unsigned long *addr, *addrs, *tmp_addrs;
int err = 0, max_cnt, inc_cnt;
char *name = NULL;
size_t cnt = 0;
char buf[256];
FILE *f;
if (access("/sys/kernel/tracing/trace", F_OK) == 0)
f = fopen("/sys/kernel/tracing/available_filter_functions_addrs", "r");
else
f = fopen("/sys/kernel/debug/tracing/available_filter_functions_addrs", "r");
if (!f)
return -ENOENT;
/* In my local setup, the number of entries is 50k+ so Let us initially
* allocate space to hold 64k entries. If 64k is not enough, incrementally
* increase 1k each time.
*/
max_cnt = 65536;
inc_cnt = 1024;
addrs = malloc(max_cnt * sizeof(long));
if (addrs == NULL) {
err = -ENOMEM;
goto error;
}
while (fgets(buf, sizeof(buf), f)) {
if (is_invalid_entry(buf, kernel))
continue;
free(name);
if (sscanf(buf, "%p %ms$*[^\n]\n", &addr, &name) != 2)
continue;
if (skip_entry(name))
continue;
if (cnt == max_cnt) {
max_cnt += inc_cnt;
tmp_addrs = realloc(addrs, max_cnt);
if (!tmp_addrs) {
err = -ENOMEM;
goto error;
}
addrs = tmp_addrs;
}
addrs[cnt++] = (unsigned long)addr;
}
*addrsp = addrs;
*cntp = cnt;
error:
free(name);
fclose(f);
if (err)
free(addrs);
return err;
}
static void do_bench_test(struct kprobe_multi_empty *skel, struct bpf_kprobe_multi_opts *opts)
{
long attach_start_ns, attach_end_ns;
@ -529,6 +592,37 @@ cleanup:
free(syms);
}
static void test_kprobe_multi_bench_attach_addr(bool kernel)
{
LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
struct kprobe_multi_empty *skel = NULL;
unsigned long *addrs = NULL;
size_t cnt = 0;
int err;
err = get_addrs(&addrs, &cnt, kernel);
if (err == -ENOENT) {
test__skip();
return;
}
if (!ASSERT_OK(err, "get_addrs"))
return;
skel = kprobe_multi_empty__open_and_load();
if (!ASSERT_OK_PTR(skel, "kprobe_multi_empty__open_and_load"))
goto cleanup;
opts.addrs = addrs;
opts.cnt = cnt;
do_bench_test(skel, &opts);
cleanup:
kprobe_multi_empty__destroy(skel);
free(addrs);
}
static void test_attach_override(void)
{
struct kprobe_multi_override *skel = NULL;
@ -569,6 +663,10 @@ void serial_test_kprobe_multi_bench_attach(void)
test_kprobe_multi_bench_attach(true);
if (test__start_subtest("modules"))
test_kprobe_multi_bench_attach(false);
if (test__start_subtest("kernel"))
test_kprobe_multi_bench_attach_addr(true);
if (test__start_subtest("modules"))
test_kprobe_multi_bench_attach_addr(false);
}
void test_kprobe_multi_test(void)