[PATCH 5.4 044/100] perf bpf: Avoid memory leak from perf_env__insert_btf()

Greg Kroah-Hartman
2021-11-24T13:22:47Z

From: Ian Rogers <irogers@google.com>

[ Upstream commit 4924b1f7c46711762fd0e65c135ccfbcfd6ded1f ]

perf_env__insert_btf() doesn't insert if a duplicate BTF id is
encountered and this causes a memory leak. Modify the function to return
a success/error value and then free the memory if insertion didn't
happen.

v2. Adds a return -1 when the insertion error occurs in
perf_env__fetch_btf. This doesn't affect anything as the result is
never checked.

Fixes: 3792cb2ff43b1b19 ("perf bpf: Save BTF in a rbtree in perf_env")
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/20211112074525.121633-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/util/bpf-event.c | 6 +++++-
tools/perf/util/env.c | 5 ++++-
tools/perf/util/env.h | 2 +-
3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
index c766813d56be0..782c0c8a9a836 100644
--- a/tools/perf/util/bpf-event.c
+++ b/tools/perf/util/bpf-event.c
@@ -108,7 +108,11 @@ static int perf_env__fetch_btf(struct perf_env *env,
node->data_size = data_size;
memcpy(node->data, data, data_size);

- perf_env__insert_btf(env, node);
+ if (!perf_env__insert_btf(env, node)) {
+ /* Insertion failed because of a duplicate. */
+ free(node);
+ return -1;
+ }
return 0;
}

diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index 0fafcf264d235..ef64e197bc8df 100644
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -69,12 +69,13 @@ out:
return node;
}

-void perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
+bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
{
struct rb_node *parent = NULL;
__u32 btf_id = btf_node->id;
struct btf_node *node;
struct rb_node **p;
+ bool ret = true;

down_write(&env->bpf_progs.lock);
p = &env->bpf_progs.btfs.rb_node;
@@ -88,6 +89,7 @@ void perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
p = &(*p)->rb_right;
} else {
pr_debug("duplicated btf %u\n", btf_id);
+ ret = false;
goto out;
}
}
@@ -97,6 +99,7 @@ void perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
env->bpf_progs.btfs_cnt++;
out:
up_write(&env->bpf_progs.lock);
+ return ret;
}

struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index db40906e29373..37028215d4a53 100644
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -117,6 +117,6 @@ void perf_env__insert_bpf_prog_info(struct perf_env *env,
struct bpf_prog_info_node *info_node);
struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
__u32 prog_id);
-void perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
+bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id);
#endif /* __PERF_ENV_H */
--
2.33.0