-
Notifications
You must be signed in to change notification settings - Fork 94
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
bpf/selftests: Test fentry attachment to shadowed functions
Adds a new test that tries to attach a program to fentry of two functions of the same name, one located in vmlinux and the other in bpf_testmod. To avoid conflicts with existing tests, a new function "bpf_fentry_shadow_test" was created both in vmlinux and in bpf_testmod. The previous commit fixed a bug which caused this test to fail. The verifier would always use the vmlinux function's address as the target trampoline address, hence trying to attach two programs to the same trampoline. Signed-off-by: Viktor Malik <vmalik@redhat.com>
- Loading branch information
Viktor Malik
authored and
Kernel Patches Daemon
committed
Dec 5, 2022
1 parent
75c027c
commit 54c36bd
Showing
3 changed files
with
136 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
124 changes: 124 additions & 0 deletions
124
tools/testing/selftests/bpf/prog_tests/module_attach_shadow.c
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,124 @@ | ||
// SPDX-License-Identifier: GPL-2.0 | ||
/* Copyright (c) 2022 Red Hat */ | ||
#include <test_progs.h> | ||
#include <bpf/btf.h> | ||
#include "bpf/libbpf_internal.h" | ||
#include "cgroup_helpers.h" | ||
|
||
static const char *module_name = "bpf_testmod"; | ||
static const char *symbol_name = "bpf_fentry_shadow_test"; | ||
|
||
int get_bpf_testmod_btf_fd(void) | ||
{ | ||
struct bpf_btf_info info; | ||
char name[64]; | ||
__u32 id = 0, len; | ||
int err, fd; | ||
|
||
while (true) { | ||
err = bpf_btf_get_next_id(id, &id); | ||
if (err) { | ||
log_err("failed to iterate BTF objects"); | ||
return err; | ||
} | ||
|
||
fd = bpf_btf_get_fd_by_id(id); | ||
if (fd < 0) { | ||
err = -errno; | ||
log_err("failed to get FD for BTF object #%d", id); | ||
return err; | ||
} | ||
|
||
len = sizeof(info); | ||
memset(&info, 0, sizeof(info)); | ||
info.name = ptr_to_u64(name); | ||
info.name_len = sizeof(name); | ||
|
||
err = bpf_obj_get_info_by_fd(fd, &info, &len); | ||
if (err) { | ||
err = -errno; | ||
log_err("failed to get info for BTF object #%d", id); | ||
close(fd); | ||
return err; | ||
} | ||
|
||
if (strcmp(name, module_name) == 0) | ||
return fd; | ||
|
||
close(fd); | ||
} | ||
return -ENOENT; | ||
} | ||
|
||
void test_module_fentry_shadow(void) | ||
{ | ||
struct btf *vmlinux_btf = NULL, *mod_btf = NULL; | ||
int err, i; | ||
int btf_fd[2] = {}; | ||
int prog_fd[2] = {}; | ||
int link_fd[2] = {}; | ||
__s32 btf_id[2] = {}; | ||
|
||
const struct bpf_insn trace_program[] = { | ||
BPF_MOV64_IMM(BPF_REG_0, 0), | ||
BPF_EXIT_INSN(), | ||
}; | ||
|
||
LIBBPF_OPTS(bpf_prog_load_opts, load_opts, | ||
.expected_attach_type = BPF_TRACE_FENTRY, | ||
); | ||
|
||
LIBBPF_OPTS(bpf_test_run_opts, test_opts); | ||
|
||
vmlinux_btf = btf__load_vmlinux_btf(); | ||
if (!ASSERT_OK_PTR(vmlinux_btf, "load_vmlinux_btf")) | ||
return; | ||
|
||
btf_fd[1] = get_bpf_testmod_btf_fd(); | ||
if (!ASSERT_GT(btf_fd[1], 0, "get_bpf_testmod_btf_fd")) | ||
goto out; | ||
|
||
mod_btf = btf_get_from_fd(btf_fd[1], vmlinux_btf); | ||
if (!ASSERT_OK_PTR(mod_btf, "btf_get_from_fd")) | ||
goto out; | ||
|
||
btf_id[0] = btf__find_by_name_kind(vmlinux_btf, symbol_name, BTF_KIND_FUNC); | ||
if (!ASSERT_GT(btf_id[0], 0, "btf_find_by_name")) | ||
goto out; | ||
|
||
btf_id[1] = btf__find_by_name_kind(mod_btf, symbol_name, BTF_KIND_FUNC); | ||
if (!ASSERT_GT(btf_id[1], 0, "btf_find_by_name")) | ||
goto out; | ||
|
||
for (i = 0; i < 2; i++) { | ||
load_opts.attach_btf_id = btf_id[i]; | ||
load_opts.attach_btf_obj_fd = btf_fd[i]; | ||
prog_fd[i] = bpf_prog_load(BPF_PROG_TYPE_TRACING, NULL, "GPL", | ||
trace_program, | ||
sizeof(trace_program) / sizeof(struct bpf_insn), | ||
&load_opts); | ||
if (!ASSERT_GE(prog_fd[i], 0, "bpf_prog_load")) | ||
goto out; | ||
|
||
link_fd[i] = bpf_link_create(prog_fd[i], 0, BPF_TRACE_FENTRY, NULL); | ||
if (!ASSERT_GE(link_fd[i], 0, "bpf_link_create")) | ||
goto out; | ||
} | ||
|
||
err = bpf_prog_test_run_opts(prog_fd[0], &test_opts); | ||
ASSERT_OK(err, "running test"); | ||
|
||
out: | ||
if (vmlinux_btf) | ||
btf__free(vmlinux_btf); | ||
if (mod_btf) | ||
btf__free(mod_btf); | ||
for (i = 0; i < 2; i++) { | ||
if (btf_fd[i]) | ||
close(btf_fd[i]); | ||
if (prog_fd[i]) | ||
close(prog_fd[i]); | ||
if (link_fd[i]) | ||
close(link_fd[i]); | ||
} | ||
} |