This is a note to let you know that I've just added the patch titled
tools/perf: Fix the string match for "/tmp/perf-$PID.map" files in dso__load
to the 6.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tools-perf-fix-the-string-match-for-tmp-perf-pid.map.patch
and it can be found in the queue-6.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4bee9b5489eca0c0c073f008024641d8100caa86
Author: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx>
Date: Sun Jun 23 12:18:48 2024 +0530
tools/perf: Fix the string match for "/tmp/perf-$PID.map" files in dso__load
[ Upstream commit b0979f008f1352a44cd3c8877e3eb8a1e3e1c6f3 ]
Perf test for perf probe of function from different CU fails
as below:
./perf test -vv "test perf probe of function from different CU"
116: test perf probe of function from different CU:
--- start ---
test child forked, pid 2679
Failed to find symbol foo in /tmp/perf-uprobe-different-cu-sh.Msa7iy89bx/testfile
Error: Failed to add events.
--- Cleaning up ---
"foo" does not hit any event.
Error: Failed to delete events.
---- end(-1) ----
116: test perf probe of function from different CU : FAILED!
The test does below to probe function "foo" :
# gcc -g -Og -flto -c /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.c
-o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.o
# gcc -g -Og -c /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.c
-o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.o
# gcc -g -Og -o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile
/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.o
/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.o
# ./perf probe -x /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile foo
Failed to find symbol foo in /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile
Error: Failed to add events.
Perf probe fails to find symbol foo in the executable placed in
/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7
Simple reproduce:
# mktemp -d /tmp/perf-checkXXXXXXXXXX
/tmp/perf-checkcWpuLRQI8j
# gcc -g -o test test.c
# cp test /tmp/perf-checkcWpuLRQI8j/
# nm /tmp/perf-checkcWpuLRQI8j/test | grep foo
00000000100006bc T foo
# ./perf probe -x /tmp/perf-checkcWpuLRQI8j/test foo
Failed to find symbol foo in /tmp/perf-checkcWpuLRQI8j/test
Error: Failed to add events.
But it works with any files like /tmp/perf/test. Only for
patterns with "/tmp/perf-", this fails.
Further debugging, 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-$PID.map" .
The check used "if (strncmp(self->name, "/tmp/perf-", 10) == 0)"
to match "/tmp/perf-$PID.map". With this commit, any dso in
/tmp/perf- folder will be considered separately for processing
(not only JIT created map files ). Fix this by changing the
string pattern to check for "/tmp/perf-%d.map". Add a helper
function is_perf_pid_map_name to do this check. In "struct dso",
dso->long_name holds the long name of the dso file. Since the
/tmp/perf-$PID.map check uses the complete name, use dso___long_name for
the string name.
With the fix,
# ./perf test "test perf probe of function from different CU"
117: test perf probe of function from different CU : Ok
Fixes: 56cbeacf1435 ("perf probe: Add test for regression introduced by switch to die_get_decl_file()")
Signed-off-by: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Chaitanya S Prakash <chaitanyas.prakash@xxxxxxx>
Reviewed-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: akanksha@xxxxxxxxxxxxx
Cc: kjain@xxxxxxxxxxxxx
Cc: maddy@xxxxxxxxxxxxx
Cc: disgoel@xxxxxxxxxxxxxxxxxx
Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240623064850.83720-1-atrajeev@xxxxxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index dde706b71da7b..2340c4f6d0c24 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -1652,3 +1652,15 @@ int dso__strerror_load(struct dso *dso, char *buf, size_t buflen)
scnprintf(buf, buflen, "%s", dso_load__error_str[idx]);
return 0;
}
+
+bool perf_pid_map_tid(const char *dso_name, int *tid)
+{
+ return sscanf(dso_name, "/tmp/perf-%d.map", tid) == 1;
+}
+
+bool is_perf_pid_map_name(const char *dso_name)
+{
+ int tid;
+
+ return perf_pid_map_tid(dso_name, &tid);
+}
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index df2c98402af3e..d72f3b8c37f6a 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -809,4 +809,8 @@ void reset_fd_limit(void);
u64 dso__find_global_type(struct dso *dso, u64 addr);
u64 dso__findnew_global_type(struct dso *dso, u64 addr, u64 offset);
+/* Check if dso name is of format "/tmp/perf-%d.map" */
+bool perf_pid_map_tid(const char *dso_name, int *tid);
+bool is_perf_pid_map_name(const char *dso_name);
+
#endif /* __PERF_DSO */
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 9e5940b5bc591..aee0a4cfb3836 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1799,7 +1799,8 @@ int dso__load(struct dso *dso, struct map *map)
const char *map_path = dso__long_name(dso);
mutex_lock(dso__lock(dso));
- perfmap = strncmp(dso__name(dso), "/tmp/perf-", 10) == 0;
+ perfmap = is_perf_pid_map_name(map_path);
+
if (perfmap) {
if (dso__nsinfo(dso) &&
(dso__find_perf_map(newmapname, sizeof(newmapname),
