From: Ian Rogers <irogers@google.com>

Date: Thu, 11 Nov 2021 23:45:25 -0800

Subject: perf bpf: Avoid memory leak from perf_env__insert_btf()

Git-commit: 4924b1f7c46711762fd0e65c135ccfbcfd6ded1f

Patch-mainline: v5.16-rc1

References: git-fixes

​

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: Tony Jones <tonyj@suse.de>

---

 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 4d3b4cdce176..d49cdff8fb39 100644

--- a/tools/perf/util/bpf-event.c

+++ b/tools/perf/util/bpf-event.c

@@ -119,7 +119,11 @@ 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 17f1dd0680b4..b9904896eb97 100644

--- a/tools/perf/util/env.c

+++ b/tools/perf/util/env.c

@@ -75,12 +75,13 @@ struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,

    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;

@@ -94,6 +95,7 @@ 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;

        }

    }

@@ -103,6 +105,7 @@ 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 1383876f72b3..163e5ec503a2 100644

--- a/tools/perf/util/env.h

+++ b/tools/perf/util/env.h

@@ -167,7 +167,7 @@ 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);

 int perf_env__numa_node(struct perf_env *env, int cpu);

​

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