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selftests/bpf: Add more tests for kptrs in maps
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Firstly, ensure programs successfully load when using all of the
supported maps. Then, extend existing tests to test more cases at
runtime. We are currently testing both the synchronous freeing of items
and asynchronous destruction when map is freed, but the code needs to be
adjusted a bit to be able to also accomodate support for percpu maps.

We now do a delete on the item (and update for array maps which has a
similar effect for kptrs) to perform a synchronous free of the kptr, and
test destruction both for the synchronous and asynchronous deletion.
Next time the program runs, it should observe the refcount as 1 since
all existing references should have been released by then. By running
the program after both possible paths freeing kptrs, we establish that
they correctly release resources. Next, we augment the existing test to
also test the same code path shared by all local storage maps using a
task local storage map.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230225154010.391965-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Kumar Kartikeya Dwivedi authored and Alexei Starovoitov committed Mar 1, 2023
1 parent 9db44fd commit 85521e1
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136 changes: 113 additions & 23 deletions tools/testing/selftests/bpf/prog_tests/map_kptr.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4,70 +4,160 @@

#include "map_kptr.skel.h"
#include "map_kptr_fail.skel.h"
#include "rcu_tasks_trace_gp.skel.h"

static void test_map_kptr_success(bool test_run)
{
LIBBPF_OPTS(bpf_test_run_opts, lopts);
LIBBPF_OPTS(bpf_test_run_opts, opts,
.data_in = &pkt_v4,
.data_size_in = sizeof(pkt_v4),
.repeat = 1,
);
int key = 0, ret, cpu;
struct map_kptr *skel;
int key = 0, ret;
char buf[16];
char buf[16], *pbuf;

skel = map_kptr__open_and_load();
if (!ASSERT_OK_PTR(skel, "map_kptr__open_and_load"))
return;

ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_map_kptr_ref), &opts);
ASSERT_OK(ret, "test_map_kptr_ref refcount");
ASSERT_OK(opts.retval, "test_map_kptr_ref retval");
ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_map_kptr_ref1), &opts);
ASSERT_OK(ret, "test_map_kptr_ref1 refcount");
ASSERT_OK(opts.retval, "test_map_kptr_ref1 retval");
ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_map_kptr_ref2), &opts);
ASSERT_OK(ret, "test_map_kptr_ref2 refcount");
ASSERT_OK(opts.retval, "test_map_kptr_ref2 retval");

ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_ls_map_kptr_ref1), &lopts);
ASSERT_OK(ret, "test_ls_map_kptr_ref1 refcount");
ASSERT_OK(lopts.retval, "test_ls_map_kptr_ref1 retval");

ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_ls_map_kptr_ref2), &lopts);
ASSERT_OK(ret, "test_ls_map_kptr_ref2 refcount");
ASSERT_OK(lopts.retval, "test_ls_map_kptr_ref2 retval");

if (test_run)
goto exit;

cpu = libbpf_num_possible_cpus();
if (!ASSERT_GT(cpu, 0, "libbpf_num_possible_cpus"))
goto exit;

pbuf = calloc(cpu, sizeof(buf));
if (!ASSERT_OK_PTR(pbuf, "calloc(pbuf)"))
goto exit;

ret = bpf_map__update_elem(skel->maps.array_map,
&key, sizeof(key), buf, sizeof(buf), 0);
ASSERT_OK(ret, "array_map update");
ret = bpf_map__update_elem(skel->maps.array_map,
&key, sizeof(key), buf, sizeof(buf), 0);
ASSERT_OK(ret, "array_map update2");
skel->data->ref--;
ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_map_kptr_ref3), &opts);
ASSERT_OK(ret, "test_map_kptr_ref3 refcount");
ASSERT_OK(opts.retval, "test_map_kptr_ref3 retval");

ret = bpf_map__update_elem(skel->maps.pcpu_array_map,
&key, sizeof(key), pbuf, cpu * sizeof(buf), 0);
ASSERT_OK(ret, "pcpu_array_map update");
skel->data->ref--;
ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_map_kptr_ref3), &opts);
ASSERT_OK(ret, "test_map_kptr_ref3 refcount");
ASSERT_OK(opts.retval, "test_map_kptr_ref3 retval");

ret = bpf_map__update_elem(skel->maps.hash_map,
&key, sizeof(key), buf, sizeof(buf), 0);
ASSERT_OK(ret, "hash_map update");
ret = bpf_map__delete_elem(skel->maps.hash_map, &key, sizeof(key), 0);
ASSERT_OK(ret, "hash_map delete");
skel->data->ref--;
ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_map_kptr_ref3), &opts);
ASSERT_OK(ret, "test_map_kptr_ref3 refcount");
ASSERT_OK(opts.retval, "test_map_kptr_ref3 retval");

ret = bpf_map__delete_elem(skel->maps.pcpu_hash_map, &key, sizeof(key), 0);
ASSERT_OK(ret, "pcpu_hash_map delete");
skel->data->ref--;
ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_map_kptr_ref3), &opts);
ASSERT_OK(ret, "test_map_kptr_ref3 refcount");
ASSERT_OK(opts.retval, "test_map_kptr_ref3 retval");

ret = bpf_map__update_elem(skel->maps.hash_malloc_map,
&key, sizeof(key), buf, sizeof(buf), 0);
ASSERT_OK(ret, "hash_malloc_map update");
ret = bpf_map__delete_elem(skel->maps.hash_malloc_map, &key, sizeof(key), 0);
ASSERT_OK(ret, "hash_malloc_map delete");
skel->data->ref--;
ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_map_kptr_ref3), &opts);
ASSERT_OK(ret, "test_map_kptr_ref3 refcount");
ASSERT_OK(opts.retval, "test_map_kptr_ref3 retval");

ret = bpf_map__delete_elem(skel->maps.pcpu_hash_malloc_map, &key, sizeof(key), 0);
ASSERT_OK(ret, "pcpu_hash_malloc_map delete");
skel->data->ref--;
ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_map_kptr_ref3), &opts);
ASSERT_OK(ret, "test_map_kptr_ref3 refcount");
ASSERT_OK(opts.retval, "test_map_kptr_ref3 retval");

ret = bpf_map__update_elem(skel->maps.lru_hash_map,
&key, sizeof(key), buf, sizeof(buf), 0);
ASSERT_OK(ret, "lru_hash_map update");
ret = bpf_map__delete_elem(skel->maps.lru_hash_map, &key, sizeof(key), 0);
ASSERT_OK(ret, "lru_hash_map delete");
skel->data->ref--;
ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_map_kptr_ref3), &opts);
ASSERT_OK(ret, "test_map_kptr_ref3 refcount");
ASSERT_OK(opts.retval, "test_map_kptr_ref3 retval");

ret = bpf_map__delete_elem(skel->maps.lru_pcpu_hash_map, &key, sizeof(key), 0);
ASSERT_OK(ret, "lru_pcpu_hash_map delete");
skel->data->ref--;
ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_map_kptr_ref3), &opts);
ASSERT_OK(ret, "test_map_kptr_ref3 refcount");
ASSERT_OK(opts.retval, "test_map_kptr_ref3 retval");

ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_ls_map_kptr_ref_del), &lopts);
ASSERT_OK(ret, "test_ls_map_kptr_ref_del delete");
skel->data->ref--;
ASSERT_OK(lopts.retval, "test_ls_map_kptr_ref_del retval");

free(pbuf);
exit:
map_kptr__destroy(skel);
}

void test_map_kptr(void)
static int kern_sync_rcu_tasks_trace(struct rcu_tasks_trace_gp *rcu)
{
if (test__start_subtest("success")) {
long gp_seq = READ_ONCE(rcu->bss->gp_seq);
LIBBPF_OPTS(bpf_test_run_opts, opts);

if (!ASSERT_OK(bpf_prog_test_run_opts(bpf_program__fd(rcu->progs.do_call_rcu_tasks_trace),
&opts), "do_call_rcu_tasks_trace"))
return -EFAULT;
if (!ASSERT_OK(opts.retval, "opts.retval == 0"))
return -EFAULT;
while (gp_seq == READ_ONCE(rcu->bss->gp_seq))
sched_yield();
return 0;
}

void serial_test_map_kptr(void)
{
struct rcu_tasks_trace_gp *skel;

RUN_TESTS(map_kptr_fail);

skel = rcu_tasks_trace_gp__open_and_load();
if (!ASSERT_OK_PTR(skel, "rcu_tasks_trace_gp__open_and_load"))
return;
if (!ASSERT_OK(rcu_tasks_trace_gp__attach(skel), "rcu_tasks_trace_gp__attach"))
goto end;

if (test__start_subtest("success-map")) {
test_map_kptr_success(true);

ASSERT_OK(kern_sync_rcu_tasks_trace(skel), "sync rcu_tasks_trace");
ASSERT_OK(kern_sync_rcu(), "sync rcu");
/* Observe refcount dropping to 1 on bpf_map_free_deferred */
test_map_kptr_success(false);
/* Do test_run twice, so that we see refcount going back to 1
* after we leave it in map from first iteration.
*/

ASSERT_OK(kern_sync_rcu_tasks_trace(skel), "sync rcu_tasks_trace");
ASSERT_OK(kern_sync_rcu(), "sync rcu");
/* Observe refcount dropping to 1 on synchronous delete elem */
test_map_kptr_success(true);
}

RUN_TESTS(map_kptr_fail);
end:
rcu_tasks_trace_gp__destroy(skel);
return;
}
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