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authorQuentin Monnet2021-10-22 10:47:43 +0100
committerAndrii Nakryiko2021-10-22 16:44:56 -0700
commite89ef634f81c9d90e1824ab183721f3b361472e6 (patch)
tree1eec7ee66d53cc820e11d78009bb21087e0dc7b2 /tools/bpf/bpftool
parent59f2a29c04128a46df0031d4deb4c4b07c5edcea (diff)
bpftool: Avoid leaking the JSON writer prepared for program metadata
Bpftool creates a new JSON object for writing program metadata in plain text mode, regardless of metadata being present or not. Then this writer is freed if any metadata has been found and printed, but it leaks otherwise. We cannot destroy the object unconditionally, because the destructor prints an undesirable line break. Instead, make sure the writer is created only after we have found program metadata to print. Found with valgrind. Fixes: aff52e685eb3 ("bpftool: Support dumping metadata") Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211022094743.11052-1-quentin@isovalent.com
Diffstat (limited to 'tools/bpf/bpftool')
-rw-r--r--tools/bpf/bpftool/prog.c16
1 files changed, 9 insertions, 7 deletions
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 277d51c4c5d9..f633299b1261 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -307,18 +307,12 @@ static void show_prog_metadata(int fd, __u32 num_maps)
if (printed_header)
jsonw_end_object(json_wtr);
} else {
- json_writer_t *btf_wtr = jsonw_new(stdout);
+ json_writer_t *btf_wtr;
struct btf_dumper d = {
.btf = btf,
- .jw = btf_wtr,
.is_plain_text = true,
};
- if (!btf_wtr) {
- p_err("jsonw alloc failed");
- goto out_free;
- }
-
for (i = 0; i < vlen; i++, vsi++) {
t_var = btf__type_by_id(btf, vsi->type);
name = btf__name_by_offset(btf, t_var->name_off);
@@ -328,6 +322,14 @@ static void show_prog_metadata(int fd, __u32 num_maps)
if (!printed_header) {
printf("\tmetadata:");
+
+ btf_wtr = jsonw_new(stdout);
+ if (!btf_wtr) {
+ p_err("jsonw alloc failed");
+ goto out_free;
+ }
+ d.jw = btf_wtr,
+
printed_header = true;
}