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| author | Yichong Chen <chenyichong@uniontech.com> | 2026-06-17 17:01:17 +0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-06-21 18:02:10 -0700 |
| commit | bda6a7308ef8e79cfbb7d09e48e1c7ffaa522269 (patch) | |
| tree | 2af86e933711775e9fc3a87f814bf807e6b36c74 /tools | |
| parent | d5dc200c3a3f217de072af269dd90adddf90e48d (diff) | |
| download | ath-bda6a7308ef8e79cfbb7d09e48e1c7ffaa522269.tar.gz | |
bpftool: Fix vmlinux BTF leak in cgroup commands
bpftool cgroup show and tree call libbpf_find_kernel_btf() to
resolve attach_btf names, but never release the returned BTF object.
For cgroup tree, do_show_tree_fn() is called once for each cgroup
visited by nftw(). When more than one cgroup has attached programs,
each callback overwrites btf_vmlinux with a new object and loses the
previous allocation.
Load vmlinux BTF only once during a tree walk and release it when
cgroup show or tree completes. Reset btf_vmlinux_id at the same time
so batch mode starts with clean state.
Fixes: 596f5fb2ea2a ("bpftool: implement cgroup tree for BPF_LSM_CGROUP")
Signed-off-by: Yichong Chen <chenyichong@uniontech.com>
Reviewed-by: Quentin Monnet <qmo@kernel.org>
Link: https://lore.kernel.org/r/24357C69B4405079+20260617090117.280222-1-chenyichong@uniontech.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/bpf/bpftool/cgroup.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/tools/bpf/bpftool/cgroup.c b/tools/bpf/bpftool/cgroup.c index ec356deb27c9e..ce69d1e5468e3 100644 --- a/tools/bpf/bpftool/cgroup.c +++ b/tools/bpf/bpftool/cgroup.c @@ -78,6 +78,13 @@ static unsigned int query_flags; static struct btf *btf_vmlinux; static __u32 btf_vmlinux_id; +static void free_btf_vmlinux(void) +{ + btf__free(btf_vmlinux); + btf_vmlinux = NULL; + btf_vmlinux_id = 0; +} + static enum bpf_attach_type parse_attach_type(const char *str) { const char *attach_type_str; @@ -388,6 +395,8 @@ static int do_show(int argc, char **argv) if (json_output) jsonw_end_array(json_wtr); + free_btf_vmlinux(); + exit_cgroup: close(cgroup_fd); exit: @@ -437,7 +446,9 @@ static int do_show_tree_fn(const char *fpath, const struct stat *sb, printf("%s\n", fpath); } - btf_vmlinux = libbpf_find_kernel_btf(); + if (!btf_vmlinux) + btf_vmlinux = libbpf_find_kernel_btf(); + for (i = 0; i < ARRAY_SIZE(cgroup_attach_types); i++) show_bpf_progs(cgroup_fd, cgroup_attach_types[i], ftw->level); @@ -540,6 +551,7 @@ static int do_show_tree(int argc, char **argv) if (json_output) jsonw_end_array(json_wtr); + free_btf_vmlinux(); free(cgroup_alloced); return ret; |