| Message ID | 20211110192324.920934-1-sdf@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 314f14abdeca78de6b16f97d796a9966ce4b90ae |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next,v2] bpftool: enable libbpf's strict mode by default | expand |
On Wed, Nov 10, 2021 at 11:23 AM Stanislav Fomichev <sdf@google.com> wrote: > > Otherwise, attaching with bpftool doesn't work with strict section names. > > Also: > > - add --legacy option to switch back to pre-1.0 behavior > - print a warning when program fails to load in strict mode to point > to --legacy flag > - by default, don't append / to the section name; in strict > mode it's relevant only for a small subset of prog types > LGTM. I'll wait for Quenting's ack before applying. Thanks! > + bpftool --legacy prog loadall tools/testing/selftests/bpf/test_cgroup_link.o /sys/fs/bpf/kprobe type kprobe > libbpf: failed to pin program: File exists > Error: failed to pin all programs > + bpftool prog loadall tools/testing/selftests/bpf/test_cgroup_link.o /sys/fs/bpf/kprobe type kprobe > > v2: > - strict by default (Quentin Monnet) > - add more info to --legacy description (Quentin Monnet) > - add bash completion (Quentin Monnet) > > Cc: Quentin Monnet <quentin@isovalent.com> > Cc: John Fastabend <john.fastabend@gmail.com> > Signed-off-by: Stanislav Fomichev <sdf@google.com> > --- > .../bpftool/Documentation/common_options.rst | 9 +++++ > tools/bpf/bpftool/bash-completion/bpftool | 2 +- > tools/bpf/bpftool/main.c | 13 +++++- > tools/bpf/bpftool/main.h | 3 +- > tools/bpf/bpftool/prog.c | 40 +++++++++++-------- > 5 files changed, 48 insertions(+), 19 deletions(-) > [...]
On Thu, 11 Nov 2021 at 18:19, Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote: > > On Wed, Nov 10, 2021 at 11:23 AM Stanislav Fomichev <sdf@google.com> wrote: > > > > Otherwise, attaching with bpftool doesn't work with strict section names. > > > > Also: > > > > - add --legacy option to switch back to pre-1.0 behavior > > - print a warning when program fails to load in strict mode to point > > to --legacy flag > > - by default, don't append / to the section name; in strict > > mode it's relevant only for a small subset of prog types > > > > LGTM. I'll wait for Quenting's ack before applying. Thanks! Looks good as well, thanks Stanislav! Reviewed-by: Quentin Monnet <quentin@isovalent.com> I wonder if we should display some indication ("libbpf_strict"?) in the output of "bpftool version", alongside "libbfd" and "skeleton"? It's not strictly a feature (and would always be present for newer versions), but it could help to check how a bpftool binary will behave? (I don't mind taking it as a follow-up.) Quentin
On Thu, Nov 11, 2021 at 1:07 PM Quentin Monnet <quentin@isovalent.com> wrote: > > On Thu, 11 Nov 2021 at 18:19, Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote: > > > > On Wed, Nov 10, 2021 at 11:23 AM Stanislav Fomichev <sdf@google.com> wrote: > > > > > > Otherwise, attaching with bpftool doesn't work with strict section names. > > > > > > Also: > > > > > > - add --legacy option to switch back to pre-1.0 behavior > > > - print a warning when program fails to load in strict mode to point > > > to --legacy flag > > > - by default, don't append / to the section name; in strict > > > mode it's relevant only for a small subset of prog types > > > > > > > LGTM. I'll wait for Quenting's ack before applying. Thanks! > > Looks good as well, thanks Stanislav! > > Reviewed-by: Quentin Monnet <quentin@isovalent.com> > > I wonder if we should display some indication ("libbpf_strict"?) in > the output of "bpftool version", alongside "libbfd" and "skeleton"? > It's not strictly a feature (and would always be present for newer > versions), but it could help to check how a bpftool binary will > behave? (I don't mind taking it as a follow-up.) Sure, makes sense, I can follow up on that.
Hello: This patch was applied to bpf/bpf-next.git (master) by Daniel Borkmann <daniel@iogearbox.net>: On Wed, 10 Nov 2021 11:23:24 -0800 you wrote: > Otherwise, attaching with bpftool doesn't work with strict section names. > > Also: > > - add --legacy option to switch back to pre-1.0 behavior > - print a warning when program fails to load in strict mode to point > to --legacy flag > - by default, don't append / to the section name; in strict > mode it's relevant only for a small subset of prog types > > [...] Here is the summary with links: - [bpf-next,v2] bpftool: enable libbpf's strict mode by default https://git.kernel.org/bpf/bpf-next/c/314f14abdeca You are awesome, thank you!
diff --git a/tools/bpf/bpftool/Documentation/common_options.rst b/tools/bpf/bpftool/Documentation/common_options.rst index 05d06c74dcaa..75adf23202d8 100644 --- a/tools/bpf/bpftool/Documentation/common_options.rst +++ b/tools/bpf/bpftool/Documentation/common_options.rst @@ -20,3 +20,12 @@ Print all logs available, even debug-level information. This includes logs from libbpf as well as from the verifier, when attempting to load programs. + +-l, --legacy + Use legacy libbpf mode which has more relaxed BPF program + requirements. By default, bpftool has more strict requirements + about section names, changes pinning logic and doesn't support + some of the older non-BTF map declarations. + + See https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0 + for details. diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool index 88e2bcf16cca..4a1b02ff72c1 100644 --- a/tools/bpf/bpftool/bash-completion/bpftool +++ b/tools/bpf/bpftool/bash-completion/bpftool @@ -261,7 +261,7 @@ _bpftool() # Deal with options if [[ ${words[cword]} == -* ]]; then local c='--version --json --pretty --bpffs --mapcompat --debug \ - --use-loader --base-btf' + --use-loader --base-btf --legacy' COMPREPLY=( $( compgen -W "$c" -- "$cur" ) ) return 0 fi diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c index 28237d7cef67..473791e87f7d 100644 --- a/tools/bpf/bpftool/main.c +++ b/tools/bpf/bpftool/main.c @@ -31,6 +31,7 @@ bool block_mount; bool verifier_logs; bool relaxed_maps; bool use_loader; +bool legacy_libbpf; struct btf *base_btf; struct hashmap *refs_table; @@ -396,6 +397,7 @@ int main(int argc, char **argv) { "debug", no_argument, NULL, 'd' }, { "use-loader", no_argument, NULL, 'L' }, { "base-btf", required_argument, NULL, 'B' }, + { "legacy", no_argument, NULL, 'l' }, { 0 } }; int opt, ret; @@ -408,7 +410,7 @@ int main(int argc, char **argv) bin_name = argv[0]; opterr = 0; - while ((opt = getopt_long(argc, argv, "VhpjfLmndB:", + while ((opt = getopt_long(argc, argv, "VhpjfLmndB:l", options, NULL)) >= 0) { switch (opt) { case 'V': @@ -454,6 +456,9 @@ int main(int argc, char **argv) case 'L': use_loader = true; break; + case 'l': + legacy_libbpf = true; + break; default: p_err("unrecognized option '%s'", argv[optind - 1]); if (json_output) @@ -463,6 +468,12 @@ int main(int argc, char **argv) } } + if (!legacy_libbpf) { + ret = libbpf_set_strict_mode(LIBBPF_STRICT_ALL); + if (ret) + p_err("failed to enable libbpf strict mode: %d", ret); + } + argc -= optind; argv += optind; if (argc < 0) diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h index 383835c2604d..8d76d937a62b 100644 --- a/tools/bpf/bpftool/main.h +++ b/tools/bpf/bpftool/main.h @@ -57,7 +57,7 @@ static inline void *u64_to_ptr(__u64 ptr) #define HELP_SPEC_PROGRAM \ "PROG := { id PROG_ID | pinned FILE | tag PROG_TAG | name PROG_NAME }" #define HELP_SPEC_OPTIONS \ - "OPTIONS := { {-j|--json} [{-p|--pretty}] | {-d|--debug}" + "OPTIONS := { {-j|--json} [{-p|--pretty}] | {-d|--debug} | {-l|--legacy}" #define HELP_SPEC_MAP \ "MAP := { id MAP_ID | pinned FILE | name MAP_NAME }" #define HELP_SPEC_LINK \ @@ -90,6 +90,7 @@ extern bool block_mount; extern bool verifier_logs; extern bool relaxed_maps; extern bool use_loader; +extern bool legacy_libbpf; extern struct btf *base_btf; extern struct hashmap *refs_table; diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c index dea7a49ec26e..bf85c914f2fa 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -1483,8 +1483,6 @@ static int load_with_options(int argc, char **argv, bool first_prog_only) while (argc) { if (is_prefix(*argv, "type")) { - char *type; - NEXT_ARG(); if (common_prog_type != BPF_PROG_TYPE_UNSPEC) { @@ -1494,21 +1492,26 @@ static int load_with_options(int argc, char **argv, bool first_prog_only) if (!REQ_ARGS(1)) goto err_free_reuse_maps; - /* Put a '/' at the end of type to appease libbpf */ - type = malloc(strlen(*argv) + 2); - if (!type) { - p_err("mem alloc failed"); - goto err_free_reuse_maps; - } - *type = 0; - strcat(type, *argv); - strcat(type, "/"); + err = libbpf_prog_type_by_name(*argv, &common_prog_type, + &expected_attach_type); + if (err < 0) { + /* Put a '/' at the end of type to appease libbpf */ + char *type = malloc(strlen(*argv) + 2); - err = get_prog_type_by_name(type, &common_prog_type, - &expected_attach_type); - free(type); - if (err < 0) - goto err_free_reuse_maps; + if (!type) { + p_err("mem alloc failed"); + goto err_free_reuse_maps; + } + *type = 0; + strcat(type, *argv); + strcat(type, "/"); + + err = get_prog_type_by_name(type, &common_prog_type, + &expected_attach_type); + free(type); + if (err < 0) + goto err_free_reuse_maps; + } NEXT_ARG(); } else if (is_prefix(*argv, "map")) { @@ -1731,6 +1734,11 @@ static int load_with_options(int argc, char **argv, bool first_prog_only) else bpf_object__unpin_programs(obj, pinfile); err_close_obj: + if (!legacy_libbpf) { + p_info("Warning: bpftool is now running in libbpf strict mode and has more stringent requirements about BPF programs.\n" + "If it used to work for this object file but now doesn't, see --legacy option for more details.\n"); + } + bpf_object__close(obj); err_free_reuse_maps: for (i = 0; i < old_map_fds; i++)
Otherwise, attaching with bpftool doesn't work with strict section names. Also: - add --legacy option to switch back to pre-1.0 behavior - print a warning when program fails to load in strict mode to point to --legacy flag - by default, don't append / to the section name; in strict mode it's relevant only for a small subset of prog types + bpftool --legacy prog loadall tools/testing/selftests/bpf/test_cgroup_link.o /sys/fs/bpf/kprobe type kprobe libbpf: failed to pin program: File exists Error: failed to pin all programs + bpftool prog loadall tools/testing/selftests/bpf/test_cgroup_link.o /sys/fs/bpf/kprobe type kprobe v2: - strict by default (Quentin Monnet) - add more info to --legacy description (Quentin Monnet) - add bash completion (Quentin Monnet) Cc: Quentin Monnet <quentin@isovalent.com> Cc: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> --- .../bpftool/Documentation/common_options.rst | 9 +++++ tools/bpf/bpftool/bash-completion/bpftool | 2 +- tools/bpf/bpftool/main.c | 13 +++++- tools/bpf/bpftool/main.h | 3 +- tools/bpf/bpftool/prog.c | 40 +++++++++++-------- 5 files changed, 48 insertions(+), 19 deletions(-)