152 lines
4.9 KiB
C
152 lines
4.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2023 Red Hat, Inc. */
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#include <test_progs.h>
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#include "fentry_recursive.skel.h"
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#include "fentry_recursive_target.skel.h"
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#include <bpf/btf.h>
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#include "bpf/libbpf_internal.h"
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/* Test recursive attachment of tracing progs with more than one nesting level
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* is not possible. Create a chain of attachment, verify that the last prog
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* will fail. Depending on the arguments, following cases are tested:
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*
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* - Recursive loading of tracing progs, without attaching (attach = false,
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* detach = false). The chain looks like this:
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* load target
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* load fentry1 -> target
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* load fentry2 -> fentry1 (fail)
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*
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* - Recursive attach of tracing progs (attach = true, detach = false). The
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* chain looks like this:
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* load target
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* load fentry1 -> target
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* attach fentry1 -> target
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* load fentry2 -> fentry1 (fail)
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*
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* - Recursive attach and detach of tracing progs (attach = true, detach =
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* true). This validates that attach_tracing_prog flag will be set throughout
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* the whole lifecycle of an fentry prog, independently from whether it's
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* detached. The chain looks like this:
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* load target
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* load fentry1 -> target
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* attach fentry1 -> target
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* detach fentry1
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* load fentry2 -> fentry1 (fail)
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*/
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static void test_recursive_fentry_chain(bool attach, bool detach)
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{
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struct fentry_recursive_target *target_skel = NULL;
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struct fentry_recursive *tracing_chain[2] = {};
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struct bpf_program *prog;
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int prev_fd, err;
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target_skel = fentry_recursive_target__open_and_load();
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if (!ASSERT_OK_PTR(target_skel, "fentry_recursive_target__open_and_load"))
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return;
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/* Create an attachment chain with two fentry progs */
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for (int i = 0; i < 2; i++) {
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tracing_chain[i] = fentry_recursive__open();
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if (!ASSERT_OK_PTR(tracing_chain[i], "fentry_recursive__open"))
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goto close_prog;
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/* The first prog in the chain is going to be attached to the target
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* fentry program, the second one to the previous in the chain.
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*/
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prog = tracing_chain[i]->progs.recursive_attach;
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if (i == 0) {
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prev_fd = bpf_program__fd(target_skel->progs.test1);
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err = bpf_program__set_attach_target(prog, prev_fd, "test1");
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} else {
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prev_fd = bpf_program__fd(tracing_chain[i-1]->progs.recursive_attach);
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err = bpf_program__set_attach_target(prog, prev_fd, "recursive_attach");
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}
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if (!ASSERT_OK(err, "bpf_program__set_attach_target"))
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goto close_prog;
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err = fentry_recursive__load(tracing_chain[i]);
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/* The first attach should succeed, the second fail */
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if (i == 0) {
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if (!ASSERT_OK(err, "fentry_recursive__load"))
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goto close_prog;
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if (attach) {
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err = fentry_recursive__attach(tracing_chain[i]);
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if (!ASSERT_OK(err, "fentry_recursive__attach"))
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goto close_prog;
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}
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if (detach) {
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/* Flag attach_tracing_prog should still be set, preventing
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* attachment of the following prog.
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*/
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fentry_recursive__detach(tracing_chain[i]);
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}
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} else {
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if (!ASSERT_ERR(err, "fentry_recursive__load"))
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goto close_prog;
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}
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}
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close_prog:
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fentry_recursive_target__destroy(target_skel);
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for (int i = 0; i < 2; i++) {
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fentry_recursive__destroy(tracing_chain[i]);
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}
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}
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void test_recursive_fentry(void)
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{
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if (test__start_subtest("attach"))
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test_recursive_fentry_chain(true, false);
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if (test__start_subtest("load"))
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test_recursive_fentry_chain(false, false);
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if (test__start_subtest("detach"))
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test_recursive_fentry_chain(true, true);
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}
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/* Test that a tracing prog reattachment (when we land in
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* "prog->aux->dst_trampoline and tgt_prog is NULL" branch in
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* bpf_tracing_prog_attach) does not lead to a crash due to missing attach_btf
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*/
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void test_fentry_attach_btf_presence(void)
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{
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struct fentry_recursive_target *target_skel = NULL;
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struct fentry_recursive *tracing_skel = NULL;
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struct bpf_program *prog;
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int err, link_fd, tgt_prog_fd;
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target_skel = fentry_recursive_target__open_and_load();
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if (!ASSERT_OK_PTR(target_skel, "fentry_recursive_target__open_and_load"))
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goto close_prog;
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tracing_skel = fentry_recursive__open();
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if (!ASSERT_OK_PTR(tracing_skel, "fentry_recursive__open"))
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goto close_prog;
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prog = tracing_skel->progs.recursive_attach;
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tgt_prog_fd = bpf_program__fd(target_skel->progs.fentry_target);
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err = bpf_program__set_attach_target(prog, tgt_prog_fd, "fentry_target");
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if (!ASSERT_OK(err, "bpf_program__set_attach_target"))
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goto close_prog;
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err = fentry_recursive__load(tracing_skel);
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if (!ASSERT_OK(err, "fentry_recursive__load"))
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goto close_prog;
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tgt_prog_fd = bpf_program__fd(tracing_skel->progs.recursive_attach);
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link_fd = bpf_link_create(tgt_prog_fd, 0, BPF_TRACE_FENTRY, NULL);
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if (!ASSERT_GE(link_fd, 0, "link_fd"))
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goto close_prog;
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fentry_recursive__detach(tracing_skel);
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err = fentry_recursive__attach(tracing_skel);
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ASSERT_ERR(err, "fentry_recursive__attach");
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close_prog:
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fentry_recursive_target__destroy(target_skel);
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fentry_recursive__destroy(tracing_skel);
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}
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