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    Subject[PATCH 5.10 065/154] perf bpf: Avoid memory leak from perf_env__insert_btf()
    Date
    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 c8101575dbf45..4eb02762104ba 100644
    --- a/tools/perf/util/bpf-event.c
    +++ b/tools/perf/util/bpf-event.c
    @@ -109,7 +109,11 @@ 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 f0dceb527ca38..d81ed1bc14bdc 100644
    --- a/tools/perf/util/env.c
    +++ b/tools/perf/util/env.c
    @@ -71,12 +71,13 @@ 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;
    @@ -90,6 +91,7 @@ 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;
    }
    }
    @@ -99,6 +101,7 @@ 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 a129726520064..01378a955dd5e 100644
    --- a/tools/perf/util/env.h
    +++ b/tools/perf/util/env.h
    @@ -143,7 +143,7 @@ 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);
    --
    2.33.0


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