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The test traverses all slab caches using the kmem_cache_iter and save the data into slab_result array map. And check if current task's pointer is from "task_struct" slab cache using bpf_get_kmem_cache(). Also compare the result array with /proc/slabinfo if available (when CONFIG_SLUB_DEBUG is on). Note that many of the fields in the slabinfo are transient, so it only compares the name and objsize fields. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Link: https://lore.kernel.org/r/20241010232505.1339892-4-namhyung@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
116 lines
2.9 KiB
C
116 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2024 Google */
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#include <test_progs.h>
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#include <bpf/libbpf.h>
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#include <bpf/btf.h>
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#include "kmem_cache_iter.skel.h"
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#define SLAB_NAME_MAX 32
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struct kmem_cache_result {
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char name[SLAB_NAME_MAX];
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long obj_size;
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};
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static void subtest_kmem_cache_iter_check_task_struct(struct kmem_cache_iter *skel)
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{
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LIBBPF_OPTS(bpf_test_run_opts, opts,
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.flags = 0, /* Run it with the current task */
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);
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int prog_fd = bpf_program__fd(skel->progs.check_task_struct);
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/* Get task_struct and check it if's from a slab cache */
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ASSERT_OK(bpf_prog_test_run_opts(prog_fd, &opts), "prog_test_run");
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/* The BPF program should set 'found' variable */
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ASSERT_EQ(skel->bss->task_struct_found, 1, "task_struct_found");
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}
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static void subtest_kmem_cache_iter_check_slabinfo(struct kmem_cache_iter *skel)
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{
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FILE *fp;
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int map_fd;
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char name[SLAB_NAME_MAX];
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unsigned long objsize;
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char rest_of_line[1000];
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struct kmem_cache_result r;
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int seen = 0;
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fp = fopen("/proc/slabinfo", "r");
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if (fp == NULL) {
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/* CONFIG_SLUB_DEBUG is not enabled */
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return;
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}
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map_fd = bpf_map__fd(skel->maps.slab_result);
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/* Ignore first two lines for header */
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fscanf(fp, "slabinfo - version: %*d.%*d\n");
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fscanf(fp, "# %*s %*s %*s %*s %*s %*s : %[^\n]\n", rest_of_line);
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/* Compare name and objsize only - others can be changes frequently */
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while (fscanf(fp, "%s %*u %*u %lu %*u %*u : %[^\n]\n",
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name, &objsize, rest_of_line) == 3) {
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int ret = bpf_map_lookup_elem(map_fd, &seen, &r);
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if (!ASSERT_OK(ret, "kmem_cache_lookup"))
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break;
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ASSERT_STREQ(r.name, name, "kmem_cache_name");
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ASSERT_EQ(r.obj_size, objsize, "kmem_cache_objsize");
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seen++;
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}
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ASSERT_EQ(skel->bss->kmem_cache_seen, seen, "kmem_cache_seen_eq");
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fclose(fp);
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}
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void test_kmem_cache_iter(void)
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{
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DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);
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struct kmem_cache_iter *skel = NULL;
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union bpf_iter_link_info linfo = {};
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struct bpf_link *link;
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char buf[256];
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int iter_fd;
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skel = kmem_cache_iter__open_and_load();
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if (!ASSERT_OK_PTR(skel, "kmem_cache_iter__open_and_load"))
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return;
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opts.link_info = &linfo;
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opts.link_info_len = sizeof(linfo);
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link = bpf_program__attach_iter(skel->progs.slab_info_collector, &opts);
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if (!ASSERT_OK_PTR(link, "attach_iter"))
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goto destroy;
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iter_fd = bpf_iter_create(bpf_link__fd(link));
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if (!ASSERT_GE(iter_fd, 0, "iter_create"))
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goto free_link;
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memset(buf, 0, sizeof(buf));
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while (read(iter_fd, buf, sizeof(buf) > 0)) {
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/* Read out all contents */
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printf("%s", buf);
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}
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/* Next reads should return 0 */
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ASSERT_EQ(read(iter_fd, buf, sizeof(buf)), 0, "read");
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if (test__start_subtest("check_task_struct"))
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subtest_kmem_cache_iter_check_task_struct(skel);
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if (test__start_subtest("check_slabinfo"))
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subtest_kmem_cache_iter_check_slabinfo(skel);
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close(iter_fd);
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free_link:
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bpf_link__destroy(link);
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destroy:
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kmem_cache_iter__destroy(skel);
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}
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