Patch "perf bpf: Avoid memory leak from perf_env__insert_btf()" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    perf bpf: Avoid memory leak from perf_env__insert_btf()

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     perf-bpf-avoid-memory-leak-from-perf_env__insert_btf.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit d2be9165e217322dcce0241a726bd2d59be460d9
Author: Ian Rogers <irogers@xxxxxxxxxx>
Date:   Thu Nov 11 23:45:25 2021 -0800

    perf bpf: Avoid memory leak from perf_env__insert_btf()
    
    [ 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@xxxxxxxxxx>
    Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
    Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
    Cc: Andrii Nakryiko <andrii@xxxxxxxxxx>
    Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
    Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
    Cc: John Fastabend <john.fastabend@xxxxxxxxx>
    Cc: KP Singh <kpsingh@xxxxxxxxxx>
    Cc: Mark Rutland <mark.rutland@xxxxxxx>
    Cc: Martin KaFai Lau <kafai@xxxxxx>
    Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
    Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
    Cc: Song Liu <songliubraving@xxxxxx>
    Cc: Stephane Eranian <eranian@xxxxxxxxxx>
    Cc: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
    Cc: Yonghong Song <yhs@xxxxxx>
    Cc: bpf@xxxxxxxxxxxxxxx
    Cc: netdev@xxxxxxxxxxxxxxx
    Link: http://lore.kernel.org/lkml/20211112074525.121633-1-irogers@xxxxxxxxxx
    Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

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 @@ 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;
@@ -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 */