Commit fa7f17d0 authored by Hou Tao's avatar Hou Tao Committed by Andrii Nakryiko
Browse files

bpf/selftests: Add test for writable bare tracepoint 



Add a writable bare tracepoint in bpf_testmod module, and
trigger its calling when reading /sys/kernel/bpf_testmod
with a specific buffer length. The reading will return
the value in writable context if the early return flag
is enabled in writable context.

Signed-off-by: default avatarHou Tao <houtao1@huawei.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211004094857.30868-4-hotforest@gmail.com
parent ccaf12d6

tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h

+15 −0
Original line number Diff line number Diff line
@@ -34,6 +34,21 @@ DECLARE_TRACE(bpf_testmod_test_write_bare, 
	TP_ARGS(task, ctx)

);



#undef BPF_TESTMOD_DECLARE_TRACE

#ifdef DECLARE_TRACE_WRITABLE

#define BPF_TESTMOD_DECLARE_TRACE(call, proto, args, size) \

	DECLARE_TRACE_WRITABLE(call, PARAMS(proto), PARAMS(args), size)

#else

#define BPF_TESTMOD_DECLARE_TRACE(call, proto, args, size) \

	DECLARE_TRACE(call, PARAMS(proto), PARAMS(args))

#endif



BPF_TESTMOD_DECLARE_TRACE(bpf_testmod_test_writable_bare,

	TP_PROTO(struct bpf_testmod_test_writable_ctx *ctx),

	TP_ARGS(ctx),

	sizeof(struct bpf_testmod_test_writable_ctx)

);



#endif /* _BPF_TESTMOD_EVENTS_H */



#undef TRACE_INCLUDE_PATH

tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c

+10 −0
Original line number Diff line number Diff line
@@ -50,6 +50,16 @@ bpf_testmod_test_read(struct file *file, struct kobject *kobj, 
	if (bpf_testmod_loop_test(101) > 100)

		trace_bpf_testmod_test_read(current, &ctx);



	/* Magic number to enable writable tp */

	if (len == 64) {

		struct bpf_testmod_test_writable_ctx writable = {

			.val = 1024,

		};

		trace_bpf_testmod_test_writable_bare(&writable);

		if (writable.early_ret)

			return snprintf(buf, len, "%d\n", writable.val);

	}



	return -EIO; /* always fail */

}

EXPORT_SYMBOL(bpf_testmod_test_read);

tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h

+5 −0
Original line number Diff line number Diff line
@@ -17,4 +17,9 @@ struct bpf_testmod_test_write_ctx { 
	size_t len;

};



struct bpf_testmod_test_writable_ctx {

	bool early_ret;

	int val;

};



#endif /* _BPF_TESTMOD_H */

tools/testing/selftests/bpf/prog_tests/module_attach.c

+35 −0
Original line number Diff line number Diff line
@@ -2,10 +2,36 @@ 
/* Copyright (c) 2020 Facebook */



#include <test_progs.h>

#include <stdbool.h>

#include "test_module_attach.skel.h"



static int duration;



static int trigger_module_test_writable(int *val)

{

	int fd, err;

	char buf[65];

	ssize_t rd;



	fd = open(BPF_TESTMOD_TEST_FILE, O_RDONLY);

	err = -errno;

	if (!ASSERT_GE(fd, 0, "testmode_file_open"))

		return err;



	rd = read(fd, buf, sizeof(buf) - 1);

	err = -errno;

	if (!ASSERT_GT(rd, 0, "testmod_file_rd_val")) {

		close(fd);

		return err;

	}



	buf[rd] = '\0';

	*val = strtol(buf, NULL, 0);

	close(fd);



	return 0;

}



static int delete_module(const char *name, int flags)

{

	return syscall(__NR_delete_module, name, flags);
@@ -19,6 +45,7 @@ void test_module_attach(void) 
	struct test_module_attach__bss *bss;

	struct bpf_link *link;

	int err;

	int writable_val = 0;



	skel = test_module_attach__open();

	if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
@@ -51,6 +78,14 @@ void test_module_attach(void) 
	ASSERT_EQ(bss->fexit_ret, -EIO, "fexit_tet");

	ASSERT_EQ(bss->fmod_ret_read_sz, READ_SZ, "fmod_ret");



	bss->raw_tp_writable_bare_early_ret = true;

	bss->raw_tp_writable_bare_out_val = 0xf1f2f3f4;

	ASSERT_OK(trigger_module_test_writable(&writable_val),

		  "trigger_writable");

	ASSERT_EQ(bss->raw_tp_writable_bare_in_val, 1024, "writable_test_in");

	ASSERT_EQ(bss->raw_tp_writable_bare_out_val, writable_val,

		  "writable_test_out");



	test_module_attach__detach(skel);



	/* attach fentry/fexit and make sure it get's module reference */

tools/testing/selftests/bpf/progs/test_module_attach.c

+14 −0
Original line number Diff line number Diff line
@@ -27,6 +27,20 @@ int BPF_PROG(handle_raw_tp_bare, 
	return 0;

}



int raw_tp_writable_bare_in_val = 0;

int raw_tp_writable_bare_early_ret = 0;

int raw_tp_writable_bare_out_val = 0;



SEC("raw_tp.w/bpf_testmod_test_writable_bare")

int BPF_PROG(handle_raw_tp_writable_bare,

	     struct bpf_testmod_test_writable_ctx *writable)

{

	raw_tp_writable_bare_in_val = writable->val;

	writable->early_ret = raw_tp_writable_bare_early_ret;

	writable->val = raw_tp_writable_bare_out_val;

	return 0;

}



__u32 tp_btf_read_sz = 0;



SEC("tp_btf/bpf_testmod_test_read")