| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <a5334a37943a497a94b6fc9db8aced56@huawei.com>
Date: Thu, 12 Sep 2024 10:09:05 +0000
From: duchangbin <changbin.du@...wei.com>
To: Adrian Hunter <adrian.hunter@...el.com>
CC: duchangbin <changbin.du@...wei.com>, Peter Zijlstra
<peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, "Arnaldo Carvalho de
Melo" <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, Nathan
Chancellor <nathan@...nel.org>, Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa
<jolsa@...nel.org>, "Ian Rogers" <irogers@...gle.com>, "Liang, Kan"
<kan.liang@...ux.intel.com>, "Nick Desaulniers" <ndesaulniers@...gle.com>,
Bill Wendling <morbo@...gle.com>, Justin Stitt <justinstitt@...gle.com>,
"linux-perf-users@...r.kernel.org" <linux-perf-users@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"llvm@...ts.linux.dev" <llvm@...ts.linux.dev>, "Wanghui (OS Kernel Lab,
Beijing)" <hw.huiwang@...wei.com>
Subject: Re: [PATCH v6 1/8] perf: support specify vdso path in cmdline
Hi, Adrian,
On Wed, Sep 11, 2024 at 11:03:21AM +0300, Adrian Hunter wrote:
> On 25/07/24 05:15, Changbin Du wrote:
> > The vdso dumped from process memory (in buildid-cache) lacks debugging
> > info. To annotate vdso symbols with source lines we need specify a
> > debugging version.
> >
> > For x86, we can find them from your local build as
> > arch/x86/entry/vdso/vdso{32,64}.so.dbg. Or they may reside in
> > /lib/modules/<version>/vdso/vdso{32,64}.so on Ubuntu. But notice that
> > the buildid has to match.
> >
> > $ sudo perf record -a
> > $ sudo perf report --objdump=llvm-objdump \
> > --vdso arch/x86/entry/vdso/vdso64.so.dbg,arch/x86/entry/vdso/vdso32.so.dbg
> >
> > Samples: 17K of event 'cycles:P', 4000 Hz, Event count (approx.): 1760
> > __vdso_clock_gettime /work/linux-host/arch/x86/entry/vdso/vdso64.so.d
> > Percent│ movq -48(%rbp),%rsi
> > │ testq %rax,%rax
> > │ ; return vread_hvclock();
> > │ movq %rax,%rdx
> > │ ; if (unlikely(!vdso_cycles_ok(cycles)))
> > │ ↑ js eb
> > │ ↑ jmp 74
> > │ ; ts->tv_sec = vdso_ts->sec;
> > 0.02 │147: leaq 2(%rbx),%rax
> > │ shlq $4, %rax
> > │ addq %r10,%rax
> > │ ; while ((seq = READ_ONCE(vd->seq)) & 1) {
> > 9.38 │152: movl (%r10),%ecx
> >
> > When doing cross platform analysis, we also need specify the vdso path if
> > we are interested in its symbols.
> >
> > v2: update documentation.
> >
> > Signed-off-by: Changbin Du <changbin.du@...wei.com>
> > ---
> > tools/perf/Documentation/perf-annotate.txt | 3 +
> > tools/perf/Documentation/perf-c2c.txt | 3 +
> > tools/perf/Documentation/perf-inject.txt | 3 +
> > tools/perf/Documentation/perf-report.txt | 3 +
> > tools/perf/Documentation/perf-script.txt | 3 +
> > tools/perf/Documentation/perf-top.txt | 3 +
> > tools/perf/builtin-annotate.c | 2 +
> > tools/perf/builtin-c2c.c | 2 +
> > tools/perf/builtin-inject.c | 2 +
> > tools/perf/builtin-report.c | 2 +
> > tools/perf/builtin-script.c | 2 +
> > tools/perf/builtin-top.c | 2 +
> > tools/perf/util/disasm.c | 7 +-
> > tools/perf/util/symbol.c | 82 +++++++++++++++++++++-
> > tools/perf/util/symbol_conf.h | 5 ++
> > 15 files changed, 119 insertions(+), 5 deletions(-)
> >
> > diff --git a/tools/perf/Documentation/perf-annotate.txt b/tools/perf/Documentation/perf-annotate.txt
> > index b95524bea021..4b6692f9a793 100644
> > --- a/tools/perf/Documentation/perf-annotate.txt
> > +++ b/tools/perf/Documentation/perf-annotate.txt
> > @@ -58,6 +58,9 @@ OPTIONS
> > --ignore-vmlinux::
> > Ignore vmlinux files.
> >
> > +--vdso=<vdso1[,vdso2]>::
> > + Specify vdso pathnames. You can specify up to two for multiarch-support.
> > +
> > --itrace::
> > Options for decoding instruction tracing data. The options are:
> >
>
> <SNIP>
>
> > diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
> > index b10b7f005658..e0aa657e6ca0 100644
> > --- a/tools/perf/builtin-annotate.c
> > +++ b/tools/perf/builtin-annotate.c
> > @@ -742,6 +742,8 @@ int cmd_annotate(int argc, const char **argv)
> > "file", "vmlinux pathname"),
> > OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules,
> > "load module symbols - WARNING: use only with -k and LIVE kernel"),
> > + OPT_CALLBACK(0, "vdso", NULL, "vdso1[,vdso2]", "vdso pathnames",
> > + parse_vdso_pathnames),
> > OPT_BOOLEAN('l', "print-line", &annotate_opts.print_lines,
> > "print matching source lines (may be slow)"),
> > OPT_BOOLEAN('P', "full-paths", &annotate_opts.full_path,
>
> <SNIP>
>
> > diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c
> > index e10558b79504..7e26d5215640 100644
> > --- a/tools/perf/util/disasm.c
> > +++ b/tools/perf/util/disasm.c
> > @@ -16,6 +16,7 @@
> > #include "debug.h"
> > #include "disasm.h"
> > #include "dso.h"
> > +#include "vdso.h"
> > #include "env.h"
> > #include "evsel.h"
> > #include "map.h"
> > @@ -1126,7 +1127,7 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
> > if (pos && strlen(pos) < SBUILD_ID_SIZE - 2)
> > dirname(build_id_path);
> >
> > - if (dso__is_kcore(dso))
> > + if (dso__is_kcore(dso) || dso__is_vdso(dso))
>
> Sorry for very long delay.
>
> This patch (probably this bit here) breaks annotation of vdso.
> To allow for bisection, you need to arrange changes so that each
> patch leaves things in a working state.
>
> However, I disagree with adding --vdso option since with just
> patch 8 alone, it would be possible to do:
>
> perf buildid-cache --remove /work/linux/arch/x86/entry/vdso/vdso64.so.dbg
> perf buildid-cache --add /work/linux/arch/x86/entry/vdso/vdso64.so.dbg
>
> and same of vdso32.
>
> That would leave the buildid-cache containing only the debug versions,
> which would mean you will only get the debug versions, and it would only
> need to be done once per kernel instead of having to add --vdso to
> every perf command.
>
I may send patch 8 alone first and suspend the rest. I suppose mananging buildid-cache
for vdso mannually is enough for most case. So maybe it's better not get things
more complex.
>
--
Cheers,
Changbin Du
Powered by blists - more mailing lists