This is a note to let you know that I've just added the patch titled
perf callchain: Fix stitch LBR memory leaks
to the 6.11-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:
perf-callchain-fix-stitch-lbr-memory-leaks.patch
and it can be found in the queue-6.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5afb0508abbfed56b03831a30a850da737f96768
Author: Ian Rogers <irogers@xxxxxxxxxx>
Date: Wed Aug 7 22:46:43 2024 -0700
perf callchain: Fix stitch LBR memory leaks
[ Upstream commit 599c19397b17d197fc1184bbc950f163a292efc9 ]
The 'struct callchain_cursor_node' has a 'struct map_symbol' whose maps
and map members are reference counted. Ensure these values use a _get
routine to increment the reference counts and use map_symbol__exit() to
release the reference counts.
Do similar for 'struct thread's prev_lbr_cursor, but save the size of
the prev_lbr_cursor array so that it may be iterated.
Ensure that when stitch_nodes are placed on the free list the
map_symbols are exited.
Fix resolve_lbr_callchain_sample() by replacing list_replace_init() to
list_splice_init(), so the whole list is moved and nodes aren't leaked.
A reproduction of the memory leaks is possible with a leak sanitizer
build in the perf report command of:
```
$ perf record -e cycles --call-graph lbr perf test -w thloop
$ perf report --stitch-lbr
```
Reviewed-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Fixes: ff165628d72644e3 ("perf callchain: Stitch LBR call stack")
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
[ Basic tests after applying the patch, repeating the example above ]
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Anne Macedo <retpolanne@xxxxxxxxxx>
Cc: Changbin Du <changbin.du@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240808054644.1286065-1-irogers@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 8477edefc2997..706be5e4a0761 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2270,8 +2270,12 @@ static void save_lbr_cursor_node(struct thread *thread,
cursor->curr = cursor->first;
else
cursor->curr = cursor->curr->next;
+
+ map_symbol__exit(&lbr_stitch->prev_lbr_cursor[idx].ms);
memcpy(&lbr_stitch->prev_lbr_cursor[idx], cursor->curr,
sizeof(struct callchain_cursor_node));
+ lbr_stitch->prev_lbr_cursor[idx].ms.maps = maps__get(cursor->curr->ms.maps);
+ lbr_stitch->prev_lbr_cursor[idx].ms.map = map__get(cursor->curr->ms.map);
lbr_stitch->prev_lbr_cursor[idx].valid = true;
cursor->pos++;
@@ -2482,6 +2486,9 @@ static bool has_stitched_lbr(struct thread *thread,
memcpy(&stitch_node->cursor, &lbr_stitch->prev_lbr_cursor[i],
sizeof(struct callchain_cursor_node));
+ stitch_node->cursor.ms.maps = maps__get(lbr_stitch->prev_lbr_cursor[i].ms.maps);
+ stitch_node->cursor.ms.map = map__get(lbr_stitch->prev_lbr_cursor[i].ms.map);
+
if (callee)
list_add(&stitch_node->node, &lbr_stitch->lists);
else
@@ -2505,6 +2512,8 @@ static bool alloc_lbr_stitch(struct thread *thread, unsigned int max_lbr)
if (!thread__lbr_stitch(thread)->prev_lbr_cursor)
goto free_lbr_stitch;
+ thread__lbr_stitch(thread)->prev_lbr_cursor_size = max_lbr + 1;
+
INIT_LIST_HEAD(&thread__lbr_stitch(thread)->lists);
INIT_LIST_HEAD(&thread__lbr_stitch(thread)->free_lists);
@@ -2560,8 +2569,12 @@ static int resolve_lbr_callchain_sample(struct thread *thread,
max_lbr, callee);
if (!stitched_lbr && !list_empty(&lbr_stitch->lists)) {
- list_replace_init(&lbr_stitch->lists,
- &lbr_stitch->free_lists);
+ struct stitch_list *stitch_node;
+
+ list_for_each_entry(stitch_node, &lbr_stitch->lists, node)
+ map_symbol__exit(&stitch_node->cursor.ms);
+
+ list_splice_init(&lbr_stitch->lists, &lbr_stitch->free_lists);
}
memcpy(&lbr_stitch->prev_sample, sample, sizeof(*sample));
}
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 87c59aa9fe38b..0ffdd52d86d70 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -476,6 +476,7 @@ void thread__free_stitch_list(struct thread *thread)
return;
list_for_each_entry_safe(pos, tmp, &lbr_stitch->lists, node) {
+ map_symbol__exit(&pos->cursor.ms);
list_del_init(&pos->node);
free(pos);
}
@@ -485,6 +486,9 @@ void thread__free_stitch_list(struct thread *thread)
free(pos);
}
+ for (unsigned int i = 0 ; i < lbr_stitch->prev_lbr_cursor_size; i++)
+ map_symbol__exit(&lbr_stitch->prev_lbr_cursor[i].ms);
+
zfree(&lbr_stitch->prev_lbr_cursor);
free(thread__lbr_stitch(thread));
thread__set_lbr_stitch(thread, NULL);
diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index 8b4a3c69bad19..6cbf6eb2812e0 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -26,6 +26,7 @@ struct lbr_stitch {
struct list_head free_lists;
struct perf_sample prev_sample;
struct callchain_cursor_node *prev_lbr_cursor;
+ unsigned int prev_lbr_cursor_size;
};
DECLARE_RC_STRUCT(thread) {
