forked from Minki/linux
selftests/bpf: Add missing trampoline program type to trampoline_count test
Currently the trampoline_count test doesn't include any fmod_ret bpf programs, fix it to make the test cover all possible trampoline program types. Since fmod_ret bpf programs can't be attached to __set_task_comm function, as it's neither whitelisted for error injection nor a security hook, change it to bpf_modify_return_test. This patch also does some other cleanups such as removing duplicate code, dropping inconsistent comments, etc. Signed-off-by: Yuntao Wang <ytcoode@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20220519150610.601313-1-ytcoode@gmail.com
This commit is contained in:
Yuntao Wang
Andrii Nakryiko
parent
96af42c50a
commit
b23316aabf
@ -724,7 +724,7 @@ struct btf_func_model {
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#define BPF_TRAMP_F_RET_FENTRY_RET BIT(4)
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/* Each call __bpf_prog_enter + call bpf_func + call __bpf_prog_exit is ~50
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* bytes on x86. Pick a number to fit into BPF_IMAGE_SIZE / 2
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* bytes on x86.
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*/
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#define BPF_MAX_TRAMP_LINKS 38
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@ -1,126 +1,94 @@
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// SPDX-License-Identifier: GPL-2.0-only
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#define _GNU_SOURCE
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#include <sched.h>
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#include <sys/prctl.h>
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#include <test_progs.h>
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#define MAX_TRAMP_PROGS 38
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struct inst {
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struct bpf_object *obj;
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struct bpf_link *link_fentry;
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struct bpf_link *link_fexit;
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struct bpf_link *link;
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};
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static int test_task_rename(void)
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{
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int fd, duration = 0, err;
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char buf[] = "test_overhead";
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fd = open("/proc/self/comm", O_WRONLY|O_TRUNC);
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if (CHECK(fd < 0, "open /proc", "err %d", errno))
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return -1;
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err = write(fd, buf, sizeof(buf));
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if (err < 0) {
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CHECK(err < 0, "task rename", "err %d", errno);
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close(fd);
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return -1;
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}
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close(fd);
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return 0;
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}
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static struct bpf_link *load(struct bpf_object *obj, const char *name)
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static struct bpf_program *load_prog(char *file, char *name, struct inst *inst)
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{
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struct bpf_object *obj;
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struct bpf_program *prog;
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int duration = 0;
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int err;
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obj = bpf_object__open_file(file, NULL);
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if (!ASSERT_OK_PTR(obj, "obj_open_file"))
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return NULL;
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inst->obj = obj;
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err = bpf_object__load(obj);
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if (!ASSERT_OK(err, "obj_load"))
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return NULL;
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prog = bpf_object__find_program_by_name(obj, name);
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if (CHECK(!prog, "find_probe", "prog '%s' not found\n", name))
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return ERR_PTR(-EINVAL);
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return bpf_program__attach_trace(prog);
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if (!ASSERT_OK_PTR(prog, "obj_find_prog"))
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return NULL;
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return prog;
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}
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/* TODO: use different target function to run in concurrent mode */
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void serial_test_trampoline_count(void)
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{
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const char *fentry_name = "prog1";
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const char *fexit_name = "prog2";
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const char *object = "test_trampoline_count.o";
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struct inst inst[MAX_TRAMP_PROGS] = {};
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int err, i = 0, duration = 0;
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struct bpf_object *obj;
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char *file = "test_trampoline_count.o";
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char *const progs[] = { "fentry_test", "fmod_ret_test", "fexit_test" };
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struct inst inst[MAX_TRAMP_PROGS + 1] = {};
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struct bpf_program *prog;
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struct bpf_link *link;
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char comm[16] = {};
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int prog_fd, err, i;
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LIBBPF_OPTS(bpf_test_run_opts, opts);
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/* attach 'allowed' trampoline programs */
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for (i = 0; i < MAX_TRAMP_PROGS; i++) {
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obj = bpf_object__open_file(object, NULL);
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if (!ASSERT_OK_PTR(obj, "obj_open_file")) {
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obj = NULL;
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prog = load_prog(file, progs[i % ARRAY_SIZE(progs)], &inst[i]);
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if (!prog)
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goto cleanup;
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}
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err = bpf_object__load(obj);
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if (CHECK(err, "obj_load", "err %d\n", err))
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link = bpf_program__attach(prog);
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if (!ASSERT_OK_PTR(link, "attach_prog"))
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goto cleanup;
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inst[i].obj = obj;
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obj = NULL;
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if (rand() % 2) {
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link = load(inst[i].obj, fentry_name);
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if (!ASSERT_OK_PTR(link, "attach_prog")) {
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link = NULL;
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goto cleanup;
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}
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inst[i].link_fentry = link;
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} else {
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link = load(inst[i].obj, fexit_name);
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if (!ASSERT_OK_PTR(link, "attach_prog")) {
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link = NULL;
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goto cleanup;
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}
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inst[i].link_fexit = link;
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}
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inst[i].link = link;
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}
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/* and try 1 extra.. */
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obj = bpf_object__open_file(object, NULL);
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if (!ASSERT_OK_PTR(obj, "obj_open_file")) {
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obj = NULL;
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prog = load_prog(file, "fmod_ret_test", &inst[i]);
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if (!prog)
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goto cleanup;
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/* ..that needs to fail */
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link = bpf_program__attach(prog);
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if (!ASSERT_ERR_PTR(link, "attach_prog")) {
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inst[i].link = link;
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goto cleanup;
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}
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err = bpf_object__load(obj);
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if (CHECK(err, "obj_load", "err %d\n", err))
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goto cleanup_extra;
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/* ..that needs to fail */
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link = load(obj, fentry_name);
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err = libbpf_get_error(link);
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if (!ASSERT_ERR_PTR(link, "cannot attach over the limit")) {
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bpf_link__destroy(link);
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goto cleanup_extra;
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}
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/* with E2BIG error */
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ASSERT_EQ(err, -E2BIG, "proper error check");
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ASSERT_EQ(link, NULL, "ptr_is_null");
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if (!ASSERT_EQ(libbpf_get_error(link), -E2BIG, "E2BIG"))
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goto cleanup;
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if (!ASSERT_EQ(link, NULL, "ptr_is_null"))
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goto cleanup;
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/* and finaly execute the probe */
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if (CHECK_FAIL(prctl(PR_GET_NAME, comm, 0L, 0L, 0L)))
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goto cleanup_extra;
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CHECK_FAIL(test_task_rename());
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CHECK_FAIL(prctl(PR_SET_NAME, comm, 0L, 0L, 0L));
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prog_fd = bpf_program__fd(prog);
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if (!ASSERT_GE(prog_fd, 0, "bpf_program__fd"))
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goto cleanup;
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err = bpf_prog_test_run_opts(prog_fd, &opts);
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if (!ASSERT_OK(err, "bpf_prog_test_run_opts"))
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goto cleanup;
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ASSERT_EQ(opts.retval & 0xffff, 4, "bpf_modify_return_test.result");
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ASSERT_EQ(opts.retval >> 16, 1, "bpf_modify_return_test.side_effect");
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cleanup_extra:
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bpf_object__close(obj);
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cleanup:
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if (i >= MAX_TRAMP_PROGS)
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i = MAX_TRAMP_PROGS - 1;
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for (; i >= 0; i--) {
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bpf_link__destroy(inst[i].link_fentry);
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bpf_link__destroy(inst[i].link_fexit);
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bpf_link__destroy(inst[i].link);
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bpf_object__close(inst[i].obj);
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}
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}
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@ -1,20 +1,22 @@
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// SPDX-License-Identifier: GPL-2.0
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#include <stdbool.h>
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#include <stddef.h>
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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struct task_struct;
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SEC("fentry/__set_task_comm")
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int BPF_PROG(prog1, struct task_struct *tsk, const char *buf, bool exec)
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SEC("fentry/bpf_modify_return_test")
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int BPF_PROG(fentry_test, int a, int *b)
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{
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return 0;
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}
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SEC("fexit/__set_task_comm")
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int BPF_PROG(prog2, struct task_struct *tsk, const char *buf, bool exec)
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SEC("fmod_ret/bpf_modify_return_test")
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int BPF_PROG(fmod_ret_test, int a, int *b, int ret)
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{
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return 0;
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}
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SEC("fexit/bpf_modify_return_test")
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int BPF_PROG(fexit_test, int a, int *b, int ret)
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{
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return 0;
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}
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