Re: [PATCH] bpftool: Fix NULL vs IS_ERR() checking for return value of hashmap__new

On Mon, Dec 13, 2021 at 7:07 AM 林妙倩 [off-list ref] wrote:

Sorry, I forgot to do compile testing. I will test it and let you know.

Miaoqian Lin [off-list ref] 于2021年12月12日周日 13:18写道：

quoted

The hashmap__new() function does not return NULL on errors. It returns
ERR_PTR(-ENOMEM). Using IS_ERR() to check the return value to fix this.

Signed-off-by: Miaoqian Lin <redacted>
---

Please do test (not just compile test) and re-send all three patches
as one patch set instead of three independent patches. Thanks.

quoted

 tools/bpf/bpftool/link.c | 2 +-
 tools/bpf/bpftool/map.c  | 2 +-
 tools/bpf/bpftool/pids.c | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
index 2c258db0d352..0dc402a89cd8 100644
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c

@@ -306,7 +306,7 @@ static int do_show(int argc, char **argv)
        if (show_pinned) {
                link_table = hashmap__new(hash_fn_for_key_as_id,
                                          equal_fn_for_key_as_id, NULL);
-               if (!link_table) {
+               if (IS_ERR(link_table)) {
                        p_err("failed to create hashmap for pinned paths");
                        return -1;
                }

diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index cae1f1119296..af83ae37d247 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c

@@ -698,7 +698,7 @@ static int do_show(int argc, char **argv)
        if (show_pinned) {
                map_table = hashmap__new(hash_fn_for_key_as_id,
                                         equal_fn_for_key_as_id, NULL);
-               if (!map_table) {
+               if (IS_ERR(map_table)) {
                        p_err("failed to create hashmap for pinned paths");
                        return -1;
                }

diff --git a/tools/bpf/bpftool/pids.c b/tools/bpf/bpftool/pids.c
index 56b598eee043..6c4767e97061 100644
--- a/tools/bpf/bpftool/pids.c
+++ b/tools/bpf/bpftool/pids.c

@@ -101,7 +101,7 @@ int build_obj_refs_table(struct hashmap **map, enum bpf_obj_type type)
        libbpf_print_fn_t default_print;

        *map = hashmap__new(hash_fn_for_key_as_id, equal_fn_for_key_as_id, NULL);
-       if (!*map) {
+       if (IS_ERR(*map)) {
                p_err("failed to create hashmap for PID references");
                return -1;
        }
--

2.17.1