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SubjectRe: [PATCH 1/2] perf bpf: Avoid memory leak from perf_env__insert_btf
Em Fri, Nov 05, 2021 at 10:37:32PM -0700, 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.
>
> 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 | 5 ++++-
> tools/perf/util/env.c | 5 ++++-
> tools/perf/util/env.h | 2 +-
> 3 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
> index 1a7112a87736..0783b464777a 100644
> --- a/tools/perf/util/bpf-event.c
> +++ b/tools/perf/util/bpf-event.c
> @@ -120,7 +120,10 @@ 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 0;

Shouldn't this error be propagated? Song?

- Arnaldo

> }
>
> diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
> index cf773f0dec38..5b24eb010336 100644
> --- a/tools/perf/util/env.c
> +++ b/tools/perf/util/env.c
> @@ -74,12 +74,13 @@ 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;
> @@ -93,6 +94,7 @@ 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;
> }
> }
> @@ -102,6 +104,7 @@ 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.rc0.344.g81b53c2807-goog

--

- Arnaldo

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