Commit 87bd9e60 authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch 'bpf: Tracing and lsm programs re-attach' 

Jiri Olsa says:

====================

hi,
while adding test for pinning the module while there's
trampoline attach to it, I noticed that we don't allow
link detach and following re-attach for trampolines.
Adding that for tracing and lsm programs.

You need to have patch [1] from bpf tree for test module
attach test to pass.

v5 changes:
  - fixed missing hlist_del_init change
  - fixed several ASSERT calls
  - added extra patch for missing ';'
  - added ASSERT macros to lsm test
  - added acks

thanks,
jirka

[1] https://lore.kernel.org/bpf/20210326105900.151466-1-jolsa@kernel.org/


====================

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents 0ea1041b 7bb2cc19

kernel/bpf/syscall.c

+17 −6
Original line number Diff line number Diff line
@@ -2650,13 +2650,24 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog, 
	 * - if tgt_prog == NULL when this function was called using the old

	 *   raw_tracepoint_open API, and we need a target from prog->aux

	 *

         * The combination of no saved target in prog->aux, and no target

         * specified on load is illegal, and we reject that here.

	 * - if prog->aux->dst_trampoline and tgt_prog is NULL, the program

	 *   was detached and is going for re-attachment.

	 */

	if (!prog->aux->dst_trampoline && !tgt_prog) {

		err = -ENOENT;

		/*

		 * Allow re-attach for TRACING and LSM programs. If it's

		 * currently linked, bpf_trampoline_link_prog will fail.

		 * EXT programs need to specify tgt_prog_fd, so they

		 * re-attach in separate code path.

		 */

		if (prog->type != BPF_PROG_TYPE_TRACING &&

		    prog->type != BPF_PROG_TYPE_LSM) {

			err = -EINVAL;

			goto out_unlock;

		}

		btf_id = prog->aux->attach_btf_id;

		key = bpf_trampoline_compute_key(NULL, prog->aux->attach_btf, btf_id);

	}



	if (!prog->aux->dst_trampoline ||

	    (key && key != prog->aux->dst_trampoline->key)) {

kernel/bpf/trampoline.c

+2 −2
Original line number Diff line number Diff line
@@ -444,7 +444,7 @@ int bpf_trampoline_link_prog(struct bpf_prog *prog, struct bpf_trampoline *tr) 
	tr->progs_cnt[kind]++;

	err = bpf_trampoline_update(tr);

	if (err) {

		hlist_del(&prog->aux->tramp_hlist);

		hlist_del_init(&prog->aux->tramp_hlist);

		tr->progs_cnt[kind]--;

	}

out:
@@ -467,7 +467,7 @@ int bpf_trampoline_unlink_prog(struct bpf_prog *prog, struct bpf_trampoline *tr) 
		tr->extension_prog = NULL;

		goto out;

	}

	hlist_del(&prog->aux->tramp_hlist);

	hlist_del_init(&prog->aux->tramp_hlist);

	tr->progs_cnt[kind]--;

	err = bpf_trampoline_update(tr);

out:

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

+37 −15
Original line number Diff line number Diff line
@@ -3,35 +3,57 @@ 
#include <test_progs.h>

#include "fentry_test.skel.h"



void test_fentry_test(void)

static int fentry_test(struct fentry_test *fentry_skel)

{

	struct fentry_test *fentry_skel = NULL;

	int err, prog_fd, i;

	__u32 duration = 0, retval;

	struct bpf_link *link;

	__u64 *result;



	fentry_skel = fentry_test__open_and_load();

	if (CHECK(!fentry_skel, "fentry_skel_load", "fentry skeleton failed\n"))

		goto cleanup;



	err = fentry_test__attach(fentry_skel);

	if (CHECK(err, "fentry_attach", "fentry attach failed: %d\n", err))

		goto cleanup;

	if (!ASSERT_OK(err, "fentry_attach"))

		return err;



	/* Check that already linked program can't be attached again. */

	link = bpf_program__attach(fentry_skel->progs.test1);

	if (!ASSERT_ERR_PTR(link, "fentry_attach_link"))

		return -1;



	prog_fd = bpf_program__fd(fentry_skel->progs.test1);

	err = bpf_prog_test_run(prog_fd, 1, NULL, 0,

				NULL, NULL, &retval, &duration);

	CHECK(err || retval, "test_run",

	      "err %d errno %d retval %d duration %d\n",

	      err, errno, retval, duration);

	ASSERT_OK(err, "test_run");

	ASSERT_EQ(retval, 0, "test_run");



	result = (__u64 *)fentry_skel->bss;

	for (i = 0; i < 6; i++) {

		if (CHECK(result[i] != 1, "result",

			  "fentry_test%d failed err %lld\n", i + 1, result[i]))

			goto cleanup;

	for (i = 0; i < sizeof(*fentry_skel->bss) / sizeof(__u64); i++) {

		if (!ASSERT_EQ(result[i], 1, "fentry_result"))

			return -1;

	}



	fentry_test__detach(fentry_skel);



	/* zero results for re-attach test */

	memset(fentry_skel->bss, 0, sizeof(*fentry_skel->bss));

	return 0;

}



void test_fentry_test(void)

{

	struct fentry_test *fentry_skel = NULL;

	int err;



	fentry_skel = fentry_test__open_and_load();

	if (!ASSERT_OK_PTR(fentry_skel, "fentry_skel_load"))

		goto cleanup;



	err = fentry_test(fentry_skel);

	if (!ASSERT_OK(err, "fentry_first_attach"))

		goto cleanup;



	err = fentry_test(fentry_skel);

	ASSERT_OK(err, "fentry_second_attach");



cleanup:

	fentry_test__destroy(fentry_skel);

}

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

+37 −15
Original line number Diff line number Diff line
@@ -3,35 +3,57 @@ 
#include <test_progs.h>

#include "fexit_test.skel.h"



void test_fexit_test(void)

static int fexit_test(struct fexit_test *fexit_skel)

{

	struct fexit_test *fexit_skel = NULL;

	int err, prog_fd, i;

	__u32 duration = 0, retval;

	struct bpf_link *link;

	__u64 *result;



	fexit_skel = fexit_test__open_and_load();

	if (CHECK(!fexit_skel, "fexit_skel_load", "fexit skeleton failed\n"))

		goto cleanup;



	err = fexit_test__attach(fexit_skel);

	if (CHECK(err, "fexit_attach", "fexit attach failed: %d\n", err))

		goto cleanup;

	if (!ASSERT_OK(err, "fexit_attach"))

		return err;



	/* Check that already linked program can't be attached again. */

	link = bpf_program__attach(fexit_skel->progs.test1);

	if (!ASSERT_ERR_PTR(link, "fexit_attach_link"))

		return -1;



	prog_fd = bpf_program__fd(fexit_skel->progs.test1);

	err = bpf_prog_test_run(prog_fd, 1, NULL, 0,

				NULL, NULL, &retval, &duration);

	CHECK(err || retval, "test_run",

	      "err %d errno %d retval %d duration %d\n",

	      err, errno, retval, duration);

	ASSERT_OK(err, "test_run");

	ASSERT_EQ(retval, 0, "test_run");



	result = (__u64 *)fexit_skel->bss;

	for (i = 0; i < 6; i++) {

		if (CHECK(result[i] != 1, "result",

			  "fexit_test%d failed err %lld\n", i + 1, result[i]))

			goto cleanup;

	for (i = 0; i < sizeof(*fexit_skel->bss) / sizeof(__u64); i++) {

		if (!ASSERT_EQ(result[i], 1, "fexit_result"))

			return -1;

	}



	fexit_test__detach(fexit_skel);



	/* zero results for re-attach test */

	memset(fexit_skel->bss, 0, sizeof(*fexit_skel->bss));

	return 0;

}



void test_fexit_test(void)

{

	struct fexit_test *fexit_skel = NULL;

	int err;



	fexit_skel = fexit_test__open_and_load();

	if (!ASSERT_OK_PTR(fexit_skel, "fexit_skel_load"))

		goto cleanup;



	err = fexit_test(fexit_skel);

	if (!ASSERT_OK(err, "fexit_first_attach"))

		goto cleanup;



	err = fexit_test(fexit_skel);

	ASSERT_OK(err, "fexit_second_attach");



cleanup:

	fexit_test__destroy(fexit_skel);

}

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

+23 −0
Original line number Diff line number Diff line
@@ -45,12 +45,18 @@ static int trigger_module_test_write(int write_sz) 
	return 0;

}



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

{

	return syscall(__NR_delete_module, name, flags);

}



void test_module_attach(void)

{

	const int READ_SZ = 456;

	const int WRITE_SZ = 457;

	struct test_module_attach* skel;

	struct test_module_attach__bss *bss;

	struct bpf_link *link;

	int err;



	skel = test_module_attach__open();
@@ -84,6 +90,23 @@ void test_module_attach(void) 
	ASSERT_EQ(bss->fexit_ret, -EIO, "fexit_tet");

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



	test_module_attach__detach(skel);



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

	link = bpf_program__attach(skel->progs.handle_fentry);

	if (!ASSERT_OK_PTR(link, "attach_fentry"))

		goto cleanup;



	ASSERT_ERR(delete_module("bpf_testmod", 0), "delete_module");

	bpf_link__destroy(link);



	link = bpf_program__attach(skel->progs.handle_fexit);

	if (!ASSERT_OK_PTR(link, "attach_fexit"))

		goto cleanup;



	ASSERT_ERR(delete_module("bpf_testmod", 0), "delete_module");

	bpf_link__destroy(link);



cleanup:

	test_module_attach__destroy(skel);

}