mirror of https://github.com/torvalds/linux.git
146 lines
3.2 KiB
C
146 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (C) 2022. Huawei Technologies Co., Ltd */
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#define _GNU_SOURCE
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#include <sched.h>
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#include <stdbool.h>
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#include <test_progs.h>
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#include "htab_update.skel.h"
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struct htab_update_ctx {
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int fd;
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int loop;
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bool stop;
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};
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static void test_reenter_update(void)
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{
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struct htab_update *skel;
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void *value = NULL;
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unsigned int key, value_size;
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int err;
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skel = htab_update__open();
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if (!ASSERT_OK_PTR(skel, "htab_update__open"))
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return;
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bpf_program__set_autoload(skel->progs.bpf_obj_free_fields, true);
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err = htab_update__load(skel);
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if (!ASSERT_TRUE(!err, "htab_update__load") || err)
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goto out;
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skel->bss->pid = getpid();
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err = htab_update__attach(skel);
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if (!ASSERT_OK(err, "htab_update__attach"))
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goto out;
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value_size = bpf_map__value_size(skel->maps.htab);
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value = calloc(1, value_size);
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if (!ASSERT_OK_PTR(value, "calloc value"))
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goto out;
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/*
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* First update: plain insert. This should NOT trigger the re-entrancy
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* path, because there is no old element to free yet.
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*/
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key = 0;
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err = bpf_map_update_elem(bpf_map__fd(skel->maps.htab), &key, value, BPF_ANY);
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if (!ASSERT_OK(err, "first update (insert)"))
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goto out;
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/*
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* Second update: replace existing element with same key and trigger
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* the reentrancy of bpf_map_update_elem().
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* check_and_free_fields() calls bpf_obj_free_fields() on the old
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* value, which is where fentry program runs and performs a nested
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* bpf_map_update_elem(), triggering -EDEADLK.
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*/
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memset(value, 0, value_size);
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err = bpf_map_update_elem(bpf_map__fd(skel->maps.htab), &key, value, BPF_ANY);
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if (!ASSERT_OK(err, "second update (replace)"))
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goto out;
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ASSERT_EQ(skel->bss->update_err, -EDEADLK, "no reentrancy");
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out:
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htab_update__destroy(skel);
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}
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static void *htab_update_thread(void *arg)
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{
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struct htab_update_ctx *ctx = arg;
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cpu_set_t cpus;
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int i;
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/* Pinned on CPU 0 */
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CPU_ZERO(&cpus);
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CPU_SET(0, &cpus);
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pthread_setaffinity_np(pthread_self(), sizeof(cpus), &cpus);
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i = 0;
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while (i++ < ctx->loop && !ctx->stop) {
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unsigned int key = 0, value = 0;
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int err;
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err = bpf_map_update_elem(ctx->fd, &key, &value, 0);
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if (err) {
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ctx->stop = true;
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return (void *)(long)err;
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}
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}
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return NULL;
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}
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static void test_concurrent_update(void)
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{
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struct htab_update_ctx ctx;
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struct htab_update *skel;
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unsigned int i, nr;
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pthread_t *tids;
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int err;
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skel = htab_update__open_and_load();
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if (!ASSERT_OK_PTR(skel, "htab_update__open_and_load"))
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return;
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ctx.fd = bpf_map__fd(skel->maps.htab);
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ctx.loop = 1000;
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ctx.stop = false;
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nr = 4;
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tids = calloc(nr, sizeof(*tids));
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if (!ASSERT_NEQ(tids, NULL, "no mem"))
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goto out;
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for (i = 0; i < nr; i++) {
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err = pthread_create(&tids[i], NULL, htab_update_thread, &ctx);
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if (!ASSERT_OK(err, "pthread_create")) {
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unsigned int j;
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ctx.stop = true;
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for (j = 0; j < i; j++)
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pthread_join(tids[j], NULL);
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goto out;
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}
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}
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for (i = 0; i < nr; i++) {
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void *thread_err = NULL;
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pthread_join(tids[i], &thread_err);
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ASSERT_EQ(thread_err, NULL, "update error");
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}
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out:
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if (tids)
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free(tids);
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htab_update__destroy(skel);
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}
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void test_htab_update(void)
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{
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if (test__start_subtest("reenter_update"))
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test_reenter_update();
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if (test__start_subtest("concurrent_update"))
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test_concurrent_update();
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}
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