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SubjectRe: [PATCH 2/2] perf trace: Fix segfault on perf trace -i perf.data
Em Tue, Nov 12, 2013 at 08:57:00AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Tue, Nov 12, 2013 at 08:46:09AM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Tue, Nov 12, 2013 at 03:25:00PM +0900, Namhyung Kim escreveu:
> > > From: Namhyung Kim <namhyung.kim@lge.com>
>
> > > When replaying a previous record session, it'll get a segfault since
> > > it doesn't initialize evsel->priv for finding syscall id. So fix it
> > > by initialize sys_enter/exit evsel manually.
>
> > > While at it, factor out perf_evsel__init_syscall_tp() to init a
> > > syscall evsel and remove unused perf_session__has_tp().
>
> > Try to avoid these "while at it" to combine multiple patches into one
> > :-)
>
> > I'll try to do it for you this time as it fixes a real problem, thanks
> > for fixing it!
>
> So this becomes the first part of this patch, split from yours and
> massaged a bit so that by looking at the patch it becomes quickly clear
> what it is doing, please let me now if I can keep this as-is (with your
> authorship, etc).
>
> I'll test this all out after finishing the next part of the split up.

Second part, just rewrote the changelog a bit:

commit 4e8a6e566fc611b9cbec2978a52266f29cb65785
Author: Namhyung Kim <namhyung.kim@lge.com>
Date: Tue Nov 12 15:25:00 2013 +0900

perf trace: Fix segfault on perf trace -i perf.data

When replaying a previous record session, it'll get a segfault since it
doesn't initialize raw_syscalls enter/exit tracepoint's evsel->priv for
caching the format fields.

So fix it by properly initializing sys_enter/exit evsels that comes from
reading the perf.data file header.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1384237500-22991-2-git-send-email-namhyung@kernel.org
[ Split the syscall tp field caching part in the previous patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 3fa1dce6d43e..8d6ea8fbf476 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1766,16 +1766,6 @@ static int trace__process_sample(struct perf_tool *tool,
return err;
}

-static bool
-perf_session__has_tp(struct perf_session *session, const char *name)
-{
- struct perf_evsel *evsel;
-
- evsel = perf_evlist__find_tracepoint_by_name(session->evlist, name);
-
- return evsel != NULL;
-}
-
static int parse_target_str(struct trace *trace)
{
if (trace->opts.target.pid) {
@@ -2012,8 +2002,6 @@ out_error:
static int trace__replay(struct trace *trace)
{
const struct perf_evsel_str_handler handlers[] = {
- { "raw_syscalls:sys_enter", trace__sys_enter, },
- { "raw_syscalls:sys_exit", trace__sys_exit, },
{ "probe:vfs_getname", trace__vfs_getname, },
};
struct perf_data_file file = {
@@ -2021,6 +2009,7 @@ static int trace__replay(struct trace *trace)
.mode = PERF_DATA_MODE_READ,
};
struct perf_session *session;
+ struct perf_evsel *evsel;
int err = -1;

trace->tool.sample = trace__process_sample;
@@ -2052,13 +2041,29 @@ static int trace__replay(struct trace *trace)
if (err)
goto out;

- if (!perf_session__has_tp(session, "raw_syscalls:sys_enter")) {
- pr_err("Data file does not have raw_syscalls:sys_enter events\n");
+ evsel = perf_evlist__find_tracepoint_by_name(session->evlist,
+ "raw_syscalls:sys_enter");
+ if (evsel == NULL) {
+ pr_err("Data file does not have raw_syscalls:sys_enter event\n");
+ goto out;
+ }
+
+ if (perf_evsel__init_syscall_tp(evsel, trace__sys_enter) < 0 ||
+ perf_evsel__init_sc_tp_ptr_field(evsel, args)) {
+ pr_err("Error during initialize raw_syscalls:sys_enter event\n");
+ goto out;
+ }
+
+ evsel = perf_evlist__find_tracepoint_by_name(session->evlist,
+ "raw_syscalls:sys_exit");
+ if (evsel == NULL) {
+ pr_err("Data file does not have raw_syscalls:sys_exit event\n");
goto out;
}

- if (!perf_session__has_tp(session, "raw_syscalls:sys_exit")) {
- pr_err("Data file does not have raw_syscalls:sys_exit events\n");
+ if (perf_evsel__init_syscall_tp(evsel, trace__sys_exit) < 0 ||
+ perf_evsel__init_sc_tp_uint_field(evsel, ret)) {
+ pr_err("Error during initialize raw_syscalls:sys_exit event\n");
goto out;
}


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