On 17 Jun 2024, at 7:29 PM, James Clark [off-list ref] wrote:



On 17/06/2024 14:03, Athira Rajeev wrote:

quoted

commit 80d496be89ed ("perf report: Add support for profiling JIT
generated code") added support for profiling JIT generated code.
This patch handles dso's of form "/tmp/perf-$PID.map".

Some of the references doesn't check exactly for same pattern.
some uses "if (!strncmp(dso_name, "/tmp/perf-", 10))". Fix
this by using helper function is_perf_pid_map_name which looks
for proper pattern of form: "/tmp/perf-$PID.map" for these checks.

Signed-off-by: Athira Rajeev <redacted>
---
tools/perf/util/dsos.c    | 2 +-
tools/perf/util/srcline.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/dsos.c b/tools/perf/util/dsos.c
index ab3d0c01dd63..23cd02aa701d 100644
--- a/tools/perf/util/dsos.c
+++ b/tools/perf/util/dsos.c

@@ -275,7 +275,7 @@ static void dso__set_basename(struct dso *dso)

char *base, *lname;
int tid;

- if (sscanf(dso__long_name(dso), "/tmp/perf-%d.map", &tid) == 1) {
+ if (is_perf_pid_map_name(dso__long_name(dso))) {
if (asprintf(&base, "[JIT] tid %d", tid) < 0)
return;
} else {

diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c
index 9d670d8c1c08..51eb78993fe2 100644
--- a/tools/perf/util/srcline.c
+++ b/tools/perf/util/srcline.c

@@ -39,7 +39,7 @@ static const char *srcline_dso_name(struct dso *dso)

if (dso_name[0] == '[')
return NULL;

- if (!strncmp(dso_name, "/tmp/perf-", 10))
+ if (is_perf_pid_map_name(dso_name))
return NULL;

return dso_name;

Duplicate of [1] but the latest version of the other one looks like it
might have a mistake in it.

For this one I get this compilation error:

util/dsos.c: In function ‘dso__set_basename’:
util/dsos.c:279:21: error: ‘tid’ may be used uninitialized
[-Werror=maybe-uninitialized]
 279 |                 if (asprintf(&base, "[JIT] tid %d", tid) < 0)

Hi James,

Thanks for pointing this. I had my first version here: https://lore.kernel.org/linux-perf-users/5d9a9842-9b8a-428c-898f-e1ff866a6e66@intel.com/T/#m5fbfa712a411c0e09b8177d31fc1c2d12f437fa5 (local) which used regex for matching the dso name in util/symbol.c

Got suggestion from Adrian to use “sscanf” and have a helper function since this /tmp/perf-%d.map check is done in other places as well ( in util/dsos.c, util/srcline.c ). This V2 address those changes. I didn’t hit the compile error, but that is a valid one which you reported since “tid” needs to be taken care of. I will check this compile error

Thanks
Athira 

[1]:
https://lore.kernel.org/linux-perf-users/20240601125946.1741414-10-ChaitanyaS.Prakash@arm.com/ (local)