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From: David Vernet <void@manifault.com>
To: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	bpf@vger.kernel.org, Martin KaFai Lau <kafai@fb.com>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	Kumar Kartikeya Dwivedi <memxor@gmail.com>,
	Artem Savkov <asavkov@redhat.com>
Subject: Re: [PATCHv3 bpf-next 2/9] selftests/bpf: Move test_progs helpers to testing_helpers object
Date: Tue, 7 Feb 2023 08:38:09 -0600	[thread overview]
Message-ID: <Y+JiUQFyalc0aV6M@maniforge.lan> (raw)
In-Reply-To: <20230203162336.608323-3-jolsa@kernel.org>

On Fri, Feb 03, 2023 at 05:23:29PM +0100, Jiri Olsa wrote:
> Moving test_progs helpers to testing_helpers object so they can be
> used from test_verifier in following changes.
> 
> Also adding missing ifndef header guard to testing_helpers.h header.
> 
> Using stderr instead of env.stderr because un/load_bpf_testmod helpers
> will be used outside test_progs. Also at the point of calling them
> in test_progs the std files are not hijacked yet and stderr is the
> same as env.stderr.

Makes sense. Possibly something to clean up at another time but given
that we were being inconsistent with env.stdout and env.stderr in
load_bpf_testmod() in the first place, this seems totally fine.

Acked-by: David Vernet <void@manifault.com>

Left one question about kern_sync_rcu() below that need not block this
patch series, and can be addressed in a follow-up if it's even relevant.

> 
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  tools/testing/selftests/bpf/test_progs.c      | 67 +------------------
>  tools/testing/selftests/bpf/test_progs.h      |  1 -
>  tools/testing/selftests/bpf/testing_helpers.c | 63 +++++++++++++++++
>  tools/testing/selftests/bpf/testing_helpers.h | 10 +++
>  4 files changed, 75 insertions(+), 66 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
> index 6d5e3022c75f..39ceb6a1bfc6 100644
> --- a/tools/testing/selftests/bpf/test_progs.c
> +++ b/tools/testing/selftests/bpf/test_progs.c
> @@ -11,7 +11,6 @@
>  #include <signal.h>
>  #include <string.h>
>  #include <execinfo.h> /* backtrace */
> -#include <linux/membarrier.h>
>  #include <sys/sysinfo.h> /* get_nprocs */
>  #include <netinet/in.h>
>  #include <sys/select.h>
> @@ -616,68 +615,6 @@ int extract_build_id(char *build_id, size_t size)
>  	return -1;
>  }
>  
> -static int finit_module(int fd, const char *param_values, int flags)
> -{
> -	return syscall(__NR_finit_module, fd, param_values, flags);
> -}
> -
> -static int delete_module(const char *name, int flags)
> -{
> -	return syscall(__NR_delete_module, name, flags);
> -}
> -
> -/*
> - * Trigger synchronize_rcu() in kernel.
> - */
> -int kern_sync_rcu(void)
> -{
> -	return syscall(__NR_membarrier, MEMBARRIER_CMD_SHARED, 0, 0);
> -}
> -
> -static void unload_bpf_testmod(void)
> -{
> -	if (kern_sync_rcu())
> -		fprintf(env.stderr, "Failed to trigger kernel-side RCU sync!\n");
> -	if (delete_module("bpf_testmod", 0)) {
> -		if (errno == ENOENT) {
> -			if (verbose())
> -				fprintf(stdout, "bpf_testmod.ko is already unloaded.\n");
> -			return;
> -		}
> -		fprintf(env.stderr, "Failed to unload bpf_testmod.ko from kernel: %d\n", -errno);
> -		return;
> -	}
> -	if (verbose())
> -		fprintf(stdout, "Successfully unloaded bpf_testmod.ko.\n");
> -}
> -
> -static int load_bpf_testmod(void)
> -{
> -	int fd;
> -
> -	/* ensure previous instance of the module is unloaded */
> -	unload_bpf_testmod();
> -
> -	if (verbose())
> -		fprintf(stdout, "Loading bpf_testmod.ko...\n");
> -
> -	fd = open("bpf_testmod.ko", O_RDONLY);
> -	if (fd < 0) {
> -		fprintf(env.stderr, "Can't find bpf_testmod.ko kernel module: %d\n", -errno);
> -		return -ENOENT;
> -	}
> -	if (finit_module(fd, "", 0)) {
> -		fprintf(env.stderr, "Failed to load bpf_testmod.ko into the kernel: %d\n", -errno);
> -		close(fd);
> -		return -EINVAL;
> -	}
> -	close(fd);
> -
> -	if (verbose())
> -		fprintf(stdout, "Successfully loaded bpf_testmod.ko.\n");
> -	return 0;
> -}
> -
>  /* extern declarations for test funcs */
>  #define DEFINE_TEST(name)				\
>  	extern void test_##name(void) __weak;		\
> @@ -1655,7 +1592,7 @@ int main(int argc, char **argv)
>  	env.stderr = stderr;
>  
>  	env.has_testmod = true;
> -	if (!env.list_test_names && load_bpf_testmod()) {
> +	if (!env.list_test_names && load_bpf_testmod(verbose())) {
>  		fprintf(env.stderr, "WARNING! Selftests relying on bpf_testmod.ko will be skipped.\n");
>  		env.has_testmod = false;
>  	}
> @@ -1754,7 +1691,7 @@ int main(int argc, char **argv)
>  	close(env.saved_netns_fd);
>  out:
>  	if (!env.list_test_names && env.has_testmod)
> -		unload_bpf_testmod();
> +		unload_bpf_testmod(verbose());
>  
>  	free_test_selector(&env.test_selector);
>  	free_test_selector(&env.subtest_selector);
> diff --git a/tools/testing/selftests/bpf/test_progs.h b/tools/testing/selftests/bpf/test_progs.h
> index d5d51ec97ec8..b9dac3c32712 100644
> --- a/tools/testing/selftests/bpf/test_progs.h
> +++ b/tools/testing/selftests/bpf/test_progs.h
> @@ -390,7 +390,6 @@ int bpf_find_map(const char *test, struct bpf_object *obj, const char *name);
>  int compare_map_keys(int map1_fd, int map2_fd);
>  int compare_stack_ips(int smap_fd, int amap_fd, int stack_trace_len);
>  int extract_build_id(char *build_id, size_t size);
> -int kern_sync_rcu(void);
>  int trigger_module_test_read(int read_sz);
>  int trigger_module_test_write(int write_sz);
>  int write_sysctl(const char *sysctl, const char *value);
> diff --git a/tools/testing/selftests/bpf/testing_helpers.c b/tools/testing/selftests/bpf/testing_helpers.c
> index 9695318e8132..3a9e7e8e5b14 100644
> --- a/tools/testing/selftests/bpf/testing_helpers.c
> +++ b/tools/testing/selftests/bpf/testing_helpers.c
> @@ -8,6 +8,7 @@
>  #include <bpf/libbpf.h>
>  #include "test_progs.h"
>  #include "testing_helpers.h"
> +#include <linux/membarrier.h>
>  
>  int parse_num_list(const char *s, bool **num_set, int *num_set_len)
>  {
> @@ -229,3 +230,65 @@ int bpf_test_load_program(enum bpf_prog_type type, const struct bpf_insn *insns,
>  
>  	return bpf_prog_load(type, NULL, license, insns, insns_cnt, &opts);
>  }
> +
> +static int finit_module(int fd, const char *param_values, int flags)
> +{
> +	return syscall(__NR_finit_module, fd, param_values, flags);
> +}
> +
> +static int delete_module(const char *name, int flags)
> +{
> +	return syscall(__NR_delete_module, name, flags);
> +}
> +
> +void unload_bpf_testmod(bool verbose)
> +{
> +	if (kern_sync_rcu())
> +		fprintf(stderr, "Failed to trigger kernel-side RCU sync!\n");

I realize there's no behavior change here, but out of curiosity, do you
know why we need a synchronize_rcu() here? In general this feels kind of
sketchy, and like something we should just put in bpf_testmod_exit() if
it's really needed for something in the kernel.

> +	if (delete_module("bpf_testmod", 0)) {
> +		if (errno == ENOENT) {
> +			if (verbose)
> +				fprintf(stdout, "bpf_testmod.ko is already unloaded.\n");
> +			return;
> +		}
> +		fprintf(stderr, "Failed to unload bpf_testmod.ko from kernel: %d\n", -errno);
> +		return;
> +	}
> +	if (verbose)
> +		fprintf(stdout, "Successfully unloaded bpf_testmod.ko.\n");
> +}
> +
> +int load_bpf_testmod(bool verbose)
> +{
> +	int fd;
> +
> +	/* ensure previous instance of the module is unloaded */
> +	unload_bpf_testmod(verbose);
> +
> +	if (verbose)
> +		fprintf(stdout, "Loading bpf_testmod.ko...\n");
> +
> +	fd = open("bpf_testmod.ko", O_RDONLY);
> +	if (fd < 0) {
> +		fprintf(stderr, "Can't find bpf_testmod.ko kernel module: %d\n", -errno);
> +		return -ENOENT;
> +	}
> +	if (finit_module(fd, "", 0)) {
> +		fprintf(stderr, "Failed to load bpf_testmod.ko into the kernel: %d\n", -errno);
> +		close(fd);
> +		return -EINVAL;
> +	}
> +	close(fd);
> +
> +	if (verbose)
> +		fprintf(stdout, "Successfully loaded bpf_testmod.ko.\n");
> +	return 0;
> +}
> +
> +/*
> + * Trigger synchronize_rcu() in kernel.
> + */
> +int kern_sync_rcu(void)
> +{
> +	return syscall(__NR_membarrier, MEMBARRIER_CMD_SHARED, 0, 0);
> +}
> diff --git a/tools/testing/selftests/bpf/testing_helpers.h b/tools/testing/selftests/bpf/testing_helpers.h
> index 6ec00bf79cb5..7356474def27 100644
> --- a/tools/testing/selftests/bpf/testing_helpers.h
> +++ b/tools/testing/selftests/bpf/testing_helpers.h
> @@ -1,5 +1,9 @@
>  /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
>  /* Copyright (C) 2020 Facebook, Inc. */
> +
> +#ifndef __TESTING_HELPERS_H
> +#define __TESTING_HELPERS_H
> +
>  #include <stdbool.h>
>  #include <bpf/bpf.h>
>  #include <bpf/libbpf.h>
> @@ -20,3 +24,9 @@ struct test_filter_set;
>  int parse_test_list(const char *s,
>  		    struct test_filter_set *test_set,
>  		    bool is_glob_pattern);
> +
> +int load_bpf_testmod(bool verbose);
> +void unload_bpf_testmod(bool verbose);
> +int kern_sync_rcu(void);
> +
> +#endif /* __TESTING_HELPERS_H */
> -- 
> 2.39.1
> 

  reply	other threads:[~2023-02-07 14:40 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-03 16:23 [PATCHv3 bpf-next 0/9] bpf: Move kernel test kfuncs into bpf_testmod Jiri Olsa
2023-02-03 16:23 ` [PATCHv3 bpf-next 1/9] selftests/bpf: Move kfunc exports to bpf_testmod/bpf_testmod_kfunc.h Jiri Olsa
2023-02-07 14:28   ` David Vernet
2023-02-09  0:20     ` Andrii Nakryiko
2023-02-09  8:45       ` Jiri Olsa
2023-02-03 16:23 ` [PATCHv3 bpf-next 2/9] selftests/bpf: Move test_progs helpers to testing_helpers object Jiri Olsa
2023-02-07 14:38   ` David Vernet [this message]
2023-02-08  9:35     ` Jiri Olsa
2023-02-03 16:23 ` [PATCHv3 bpf-next 3/9] selftests/bpf: Use only stdout in un/load_bpf_testmod functions Jiri Olsa
2023-02-07 14:41   ` David Vernet
2023-02-08  9:44     ` Jiri Olsa
2023-02-03 16:23 ` [PATCHv3 bpf-next 4/9] selftests/bpf: Do not unload bpf_testmod in load_bpf_testmod Jiri Olsa
2023-02-03 16:23 ` [PATCHv3 bpf-next 5/9] selftests/bpf: Use un/load_bpf_testmod functions in tests Jiri Olsa
2023-02-07 14:45   ` David Vernet
2023-02-03 16:23 ` [PATCHv3 bpf-next 6/9] selftests/bpf: Load bpf_testmod for verifier test Jiri Olsa
2023-02-07 14:46   ` David Vernet
2023-02-03 16:23 ` [PATCHv3 bpf-next 7/9] selftests/bpf: Allow to use kfunc from testmod.ko in test_verifier Jiri Olsa
2023-02-07 15:34   ` David Vernet
2023-02-08 10:09     ` Jiri Olsa
2023-02-03 16:23 ` [PATCHv3 bpf-next 8/9] selftests/bpf: Remove extern from kfuncs declarations Jiri Olsa
2023-02-07 15:35   ` David Vernet
2023-02-03 16:23 ` [PATCHv3 bpf-next 9/9] bpf: Move kernel test kfuncs to bpf_testmod Jiri Olsa
2023-02-04  9:21 ` [PATCHv3 bpf-next 0/9] bpf: Move kernel test kfuncs into bpf_testmod Alexei Starovoitov
2023-02-05 18:17   ` Jiri Olsa
2023-02-05 18:36     ` Ilya Leoshkevich
2023-02-06  9:15       ` Jiri Olsa
2023-02-09  8:47         ` Jiri Olsa
2023-02-09  9:38           ` Ilya Leoshkevich

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