From: Jiri Olsa <olsajiri@gmail.com>
To: Song Liu <song@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martynas Pumputis <m@lambda.lt>,
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>,
Christoph Hellwig <hch@lst.de>,
Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [PATCH bpf-next 2/8] ftrace: Add support to resolve module symbols in ftrace_lookup_symbols
Date: Tue, 11 Oct 2022 12:07:28 +0200 [thread overview]
Message-ID: <Y0VAYM57Bi1vqPkr@krava> (raw)
In-Reply-To: <CAPhsuW5nBf2gL_ohyfkEbX3aWH2ETEGuamq2D6JaHvaCznw_2w@mail.gmail.com>
On Tue, Oct 11, 2022 at 12:05:47AM -0700, Song Liu wrote:
> On Sun, Oct 9, 2022 at 3:00 PM Jiri Olsa <jolsa@kernel.org> wrote:
> >
> > Currently ftrace_lookup_symbols iterates only over core symbols,
> > adding module_kallsyms_on_each_symbol call to check on modules
> > symbols as well.
> >
> > Also removing 'args.found == args.cnt' condition, because it's
> > already checked in kallsyms_callback function.
> >
> > Also removing 'err < 0' check, because both *kallsyms_on_each_symbol
> > functions do not return error.
> >
> > Reported-by: Martynas Pumputis <m@lambda.lt>
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
>
> Acked-by: Song Liu <song@kernel.org>
>
> > ---
> > kernel/trace/ftrace.c | 11 ++++++-----
> > 1 file changed, 6 insertions(+), 5 deletions(-)
> >
> > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> > index 447d2e2a8549..6efdba4666f4 100644
> > --- a/kernel/trace/ftrace.c
> > +++ b/kernel/trace/ftrace.c
> > @@ -8292,17 +8292,18 @@ static int kallsyms_callback(void *data, const char *name,
> > int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
> > {
> > struct kallsyms_data args;
> > - int err;
> > + int found_all;
> >
> > memset(addrs, 0, sizeof(*addrs) * cnt);
> > args.addrs = addrs;
> > args.syms = sorted_syms;
> > args.cnt = cnt;
> > args.found = 0;
> > - err = kallsyms_on_each_symbol(kallsyms_callback, &args);
> > - if (err < 0)
> > - return err;
> > - return args.found == args.cnt ? 0 : -ESRCH;
> > + found_all = kallsyms_on_each_symbol(kallsyms_callback, &args);
> > + if (found_all)
> > + return 0;
> > + found_all = module_kallsyms_on_each_symbol(kallsyms_callback, &args);
> > + return found_all ? 0 : -ESRCH;
>
> We probably need some comments about kallsym_callback and
> ftrace_lookup_symbols. It took me a while to confirm the logic for
> found_all.
ok, I wrote some info in the changelog, but I'll put it
as comment in the code as well
jirka
>
> > }
> >
> > #ifdef CONFIG_SYSCTL
> > --
> > 2.37.3
> >
next prev parent reply other threads:[~2022-10-11 10:07 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-09 21:59 [PATCH bpf-next 0/8] bpf: Fixes for kprobe multi on kernel modules Jiri Olsa
2022-10-09 21:59 ` [PATCH bpf-next 1/8] kallsyms: Make module_kallsyms_on_each_symbol generally available Jiri Olsa
2022-10-11 6:56 ` Song Liu
2022-10-09 21:59 ` [PATCH bpf-next 2/8] ftrace: Add support to resolve module symbols in ftrace_lookup_symbols Jiri Olsa
2022-10-11 7:05 ` Song Liu
2022-10-11 10:07 ` Jiri Olsa [this message]
2022-10-09 21:59 ` [PATCH bpf-next 3/8] bpf: Rename __bpf_kprobe_multi_cookie_cmp to bpf_kprobe_multi_addrs_cmp Jiri Olsa
2022-10-11 7:06 ` Song Liu
2022-10-09 21:59 ` [PATCH bpf-next 4/8] bpf: Take module reference on kprobe_multi link Jiri Olsa
2022-10-11 7:16 ` Song Liu
2022-10-11 10:09 ` Jiri Olsa
2022-10-13 18:50 ` Andrii Nakryiko
2022-10-14 10:17 ` Jiri Olsa
2022-10-09 21:59 ` [PATCH bpf-next 5/8] selftests/bpf: Add load_kallsyms_refresh function Jiri Olsa
2022-10-11 7:17 ` Song Liu
2022-10-09 21:59 ` [PATCH bpf-next 6/8] selftests/bpf: Add bpf_testmod_fentry_* functions Jiri Olsa
2022-10-11 7:24 ` Song Liu
2022-10-09 21:59 ` [PATCH bpf-next 7/8] selftests/bpf: Add kprobe_multi kmod link api tests Jiri Olsa
2022-10-11 7:27 ` Song Liu
2022-10-11 10:09 ` Jiri Olsa
2022-10-13 19:06 ` Andrii Nakryiko
2022-10-14 10:25 ` Jiri Olsa
2022-10-09 21:59 ` [PATCH bpf-next 8/8] selftests/bpf: Add kprobe_multi check to module attach test Jiri Olsa
2022-10-11 7:27 ` Song Liu
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