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SubjectRe: [PATCH v2] perf bpf: Avoid memory leak from perf_env__insert_btf
Em Thu, Nov 11, 2021 at 11:45:25PM -0800, Ian Rogers escreveu:
> 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.

Thanks, applied.

- Arnaldo


> Fixes: 3792cb2ff43b ("perf bpf: Save BTF in a rbtree in perf_env")
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
> 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);
> --
> 2.34.0.rc1.387.gb447b232ab-goog

--

- Arnaldo

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