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linux/tools/testing/selftests/bpf/prog_tests/attach_probe.c
Andrii Nakryiko df78da2726 selftests/bpf: Few fixes for selftests/bpf built in release mode 
Fix few issues found when building and running test_progs in
release mode.

First, potentially uninitialized idx variable in xskxceiver,
force-initialize to zero to satisfy compiler.

Few instances of defining uprobe trigger functions break in release mode
unless marked as noinline, due to being static. Add noinline to make
sure everything works.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/bpf/20220816001929.369487-5-andrii@kernel.org
2022-08-17 22:43:58 +02:00

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// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
#include "test_attach_probe.skel.h"
/* this is how USDT semaphore is actually defined, except volatile modifier */
volatile unsigned short uprobe_ref_ctr __attribute__((unused)) __attribute((section(".probes")));
/* uprobe attach point */
static noinline void trigger_func(void)
{
asm volatile ("");
}
/* attach point for byname uprobe */
static noinline void trigger_func2(void)
{
asm volatile ("");
}
/* attach point for byname sleepable uprobe */
static noinline void trigger_func3(void)
{
asm volatile ("");
}
static char test_data[] = "test_data";
void test_attach_probe(void)
{
DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts);
struct bpf_link *kprobe_link, *kretprobe_link;
struct bpf_link *uprobe_link, *uretprobe_link;
struct test_attach_probe* skel;
ssize_t uprobe_offset, ref_ctr_offset;
struct bpf_link *uprobe_err_link;
bool legacy;
char *mem;
/* Check if new-style kprobe/uprobe API is supported.
* Kernels that support new FD-based kprobe and uprobe BPF attachment
* through perf_event_open() syscall expose
* /sys/bus/event_source/devices/kprobe/type and
* /sys/bus/event_source/devices/uprobe/type files, respectively. They
* contain magic numbers that are passed as "type" field of
* perf_event_attr. Lack of such file in the system indicates legacy
* kernel with old-style kprobe/uprobe attach interface through
* creating per-probe event through tracefs. For such cases
* ref_ctr_offset feature is not supported, so we don't test it.
*/
legacy = access("/sys/bus/event_source/devices/kprobe/type", F_OK) != 0;
uprobe_offset = get_uprobe_offset(&trigger_func);
if (!ASSERT_GE(uprobe_offset, 0, "uprobe_offset"))
return;
ref_ctr_offset = get_rel_offset((uintptr_t)&uprobe_ref_ctr);
if (!ASSERT_GE(ref_ctr_offset, 0, "ref_ctr_offset"))
return;
skel = test_attach_probe__open();
if (!ASSERT_OK_PTR(skel, "skel_open"))
return;
/* sleepable kprobe test case needs flags set before loading */
if (!ASSERT_OK(bpf_program__set_flags(skel->progs.handle_kprobe_sleepable,
BPF_F_SLEEPABLE), "kprobe_sleepable_flags"))
goto cleanup;
if (!ASSERT_OK(test_attach_probe__load(skel), "skel_load"))
goto cleanup;
if (!ASSERT_OK_PTR(skel->bss, "check_bss"))
goto cleanup;
/* manual-attach kprobe/kretprobe */
kprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kprobe,
false /* retprobe */,
SYS_NANOSLEEP_KPROBE_NAME);
if (!ASSERT_OK_PTR(kprobe_link, "attach_kprobe"))
goto cleanup;
skel->links.handle_kprobe = kprobe_link;
kretprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kretprobe,
true /* retprobe */,
SYS_NANOSLEEP_KPROBE_NAME);
if (!ASSERT_OK_PTR(kretprobe_link, "attach_kretprobe"))
goto cleanup;
skel->links.handle_kretprobe = kretprobe_link;
/* auto-attachable kprobe and kretprobe */
skel->links.handle_kprobe_auto = bpf_program__attach(skel->progs.handle_kprobe_auto);
ASSERT_OK_PTR(skel->links.handle_kprobe_auto, "attach_kprobe_auto");
skel->links.handle_kretprobe_auto = bpf_program__attach(skel->progs.handle_kretprobe_auto);
ASSERT_OK_PTR(skel->links.handle_kretprobe_auto, "attach_kretprobe_auto");
if (!legacy)
ASSERT_EQ(uprobe_ref_ctr, 0, "uprobe_ref_ctr_before");
uprobe_opts.retprobe = false;
uprobe_opts.ref_ctr_offset = legacy ? 0 : ref_ctr_offset;
uprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe,
0 /* self pid */,
"/proc/self/exe",
uprobe_offset,
&uprobe_opts);
if (!ASSERT_OK_PTR(uprobe_link, "attach_uprobe"))
goto cleanup;
skel->links.handle_uprobe = uprobe_link;
if (!legacy)
ASSERT_GT(uprobe_ref_ctr, 0, "uprobe_ref_ctr_after");
/* if uprobe uses ref_ctr, uretprobe has to use ref_ctr as well */
uprobe_opts.retprobe = true;
uprobe_opts.ref_ctr_offset = legacy ? 0 : ref_ctr_offset;
uretprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uretprobe,
-1 /* any pid */,
"/proc/self/exe",
uprobe_offset, &uprobe_opts);
if (!ASSERT_OK_PTR(uretprobe_link, "attach_uretprobe"))
goto cleanup;
skel->links.handle_uretprobe = uretprobe_link;
/* verify auto-attach fails for old-style uprobe definition */
uprobe_err_link = bpf_program__attach(skel->progs.handle_uprobe_byname);
if (!ASSERT_EQ(libbpf_get_error(uprobe_err_link), -EOPNOTSUPP,
"auto-attach should fail for old-style name"))
goto cleanup;
uprobe_opts.func_name = "trigger_func2";
uprobe_opts.retprobe = false;
uprobe_opts.ref_ctr_offset = 0;
skel->links.handle_uprobe_byname =
bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe_byname,
0 /* this pid */,
"/proc/self/exe",
0, &uprobe_opts);
if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname, "attach_uprobe_byname"))
goto cleanup;
/* verify auto-attach works */
skel->links.handle_uretprobe_byname =
bpf_program__attach(skel->progs.handle_uretprobe_byname);
if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname, "attach_uretprobe_byname"))
goto cleanup;
/* test attach by name for a library function, using the library
* as the binary argument. libc.so.6 will be resolved via dlopen()/dlinfo().
*/
uprobe_opts.func_name = "malloc";
uprobe_opts.retprobe = false;
skel->links.handle_uprobe_byname2 =
bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe_byname2,
0 /* this pid */,
"libc.so.6",
0, &uprobe_opts);
if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname2, "attach_uprobe_byname2"))
goto cleanup;
uprobe_opts.func_name = "free";
uprobe_opts.retprobe = true;
skel->links.handle_uretprobe_byname2 =
bpf_program__attach_uprobe_opts(skel->progs.handle_uretprobe_byname2,
-1 /* any pid */,
"libc.so.6",
0, &uprobe_opts);
if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname2, "attach_uretprobe_byname2"))
goto cleanup;
/* sleepable kprobes should not attach successfully */
skel->links.handle_kprobe_sleepable = bpf_program__attach(skel->progs.handle_kprobe_sleepable);
if (!ASSERT_ERR_PTR(skel->links.handle_kprobe_sleepable, "attach_kprobe_sleepable"))
goto cleanup;
/* test sleepable uprobe and uretprobe variants */
skel->links.handle_uprobe_byname3_sleepable = bpf_program__attach(skel->progs.handle_uprobe_byname3_sleepable);
if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname3_sleepable, "attach_uprobe_byname3_sleepable"))
goto cleanup;
skel->links.handle_uprobe_byname3 = bpf_program__attach(skel->progs.handle_uprobe_byname3);
if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname3, "attach_uprobe_byname3"))
goto cleanup;
skel->links.handle_uretprobe_byname3_sleepable = bpf_program__attach(skel->progs.handle_uretprobe_byname3_sleepable);
if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname3_sleepable, "attach_uretprobe_byname3_sleepable"))
goto cleanup;
skel->links.handle_uretprobe_byname3 = bpf_program__attach(skel->progs.handle_uretprobe_byname3);
if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname3, "attach_uretprobe_byname3"))
goto cleanup;
skel->bss->user_ptr = test_data;
/* trigger & validate kprobe && kretprobe */
usleep(1);
/* trigger & validate shared library u[ret]probes attached by name */
mem = malloc(1);
free(mem);
/* trigger & validate uprobe & uretprobe */
trigger_func();
/* trigger & validate uprobe attached by name */
trigger_func2();
/* trigger & validate sleepable uprobe attached by name */
trigger_func3();
ASSERT_EQ(skel->bss->kprobe_res, 1, "check_kprobe_res");
ASSERT_EQ(skel->bss->kprobe2_res, 11, "check_kprobe_auto_res");
ASSERT_EQ(skel->bss->kretprobe_res, 2, "check_kretprobe_res");
ASSERT_EQ(skel->bss->kretprobe2_res, 22, "check_kretprobe_auto_res");
ASSERT_EQ(skel->bss->uprobe_res, 3, "check_uprobe_res");
ASSERT_EQ(skel->bss->uretprobe_res, 4, "check_uretprobe_res");
ASSERT_EQ(skel->bss->uprobe_byname_res, 5, "check_uprobe_byname_res");
ASSERT_EQ(skel->bss->uretprobe_byname_res, 6, "check_uretprobe_byname_res");
ASSERT_EQ(skel->bss->uprobe_byname2_res, 7, "check_uprobe_byname2_res");
ASSERT_EQ(skel->bss->uretprobe_byname2_res, 8, "check_uretprobe_byname2_res");
ASSERT_EQ(skel->bss->uprobe_byname3_sleepable_res, 9, "check_uprobe_byname3_sleepable_res");
ASSERT_EQ(skel->bss->uprobe_byname3_res, 10, "check_uprobe_byname3_res");
ASSERT_EQ(skel->bss->uretprobe_byname3_sleepable_res, 11, "check_uretprobe_byname3_sleepable_res");
ASSERT_EQ(skel->bss->uretprobe_byname3_res, 12, "check_uretprobe_byname3_res");
cleanup:
test_attach_probe__destroy(skel);
ASSERT_EQ(uprobe_ref_ctr, 0, "uprobe_ref_ctr_cleanup");
}
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