* [PATCH v4 1/2] tools/bpf/bpftool: Reset vmlinux BTF after map commands
[not found] <20260624025055.1574875-1-chenyichong@uniontech.com>
@ 2026-06-24 2:50 ` Yichong Chen
2026-06-24 2:50 ` [PATCH v4 2/2] tools/bpf/bpftool: Reset vmlinux BTF after struct_ops commands Yichong Chen
1 sibling, 0 replies; 3+ messages in thread
From: Yichong Chen @ 2026-06-24 2:50 UTC (permalink / raw)
To: emil, qmo, ast, daniel, andrii, eddyz87, memxor
Cc: chenyichong, martin.lau, song, yonghong.song, jolsa, jiayuan.chen,
bpf, linux-kernel
get_map_kv_btf() caches the vmlinux BTF object when a map uses
btf_vmlinux_value_type_id. map dump released that object when the
command completed, but left the global pointer stale.
The same cached object can also be returned to print_key_value(), which
freed it directly. That leaves btf_vmlinux dangling before the command
cleanup path runs.
Use free_map_kv_btf() for per-entry cleanup, and reset the cached
btf_vmlinux pointer when the map command releases the object. This keeps
batch mode from reusing a freed BTF object.
Fixes: 4e1ea33292ff ("bpftool: Support dumping a map with btf_vmlinux_value_type_id")
Signed-off-by: Yichong Chen <chenyichong@uniontech.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
---
tools/bpf/bpftool/map.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 7ebf7dbcfba4..a265ad3afbb0 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -790,6 +790,12 @@ static int maps_have_btf(int *fds, int nb_fds)
static struct btf *btf_vmlinux;
+static void free_btf_vmlinux(void)
+{
+ btf__free(btf_vmlinux);
+ btf_vmlinux = NULL;
+}
+
static int get_map_kv_btf(const struct bpf_map_info *info, struct btf **btf)
{
int err = 0;
@@ -958,7 +964,7 @@ static int do_dump(int argc, char **argv)
close(fds[i]);
exit_free:
free(fds);
- btf__free(btf_vmlinux);
+ free_btf_vmlinux();
return err;
}
@@ -1049,7 +1055,7 @@ static void print_key_value(struct bpf_map_info *info, void *key,
btf_wtr = get_btf_writer();
if (!btf_wtr) {
p_info("failed to create json writer for btf. falling back to plain output");
- btf__free(btf);
+ free_map_kv_btf(btf);
btf = NULL;
print_entry_plain(info, key, value);
} else {
@@ -1065,7 +1071,7 @@ static void print_key_value(struct bpf_map_info *info, void *key,
} else {
print_entry_plain(info, key, value);
}
- btf__free(btf);
+ free_map_kv_btf(btf);
}
static int do_lookup(int argc, char **argv)
--
2.51.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH v4 2/2] tools/bpf/bpftool: Reset vmlinux BTF after struct_ops commands
[not found] <20260624025055.1574875-1-chenyichong@uniontech.com>
2026-06-24 2:50 ` [PATCH v4 1/2] tools/bpf/bpftool: Reset vmlinux BTF after map commands Yichong Chen
@ 2026-06-24 2:50 ` Yichong Chen
2026-06-29 7:45 ` Emil Tsalapatis
1 sibling, 1 reply; 3+ messages in thread
From: Yichong Chen @ 2026-06-24 2:50 UTC (permalink / raw)
To: emil, qmo, ast, daniel, andrii, eddyz87, memxor
Cc: chenyichong, martin.lau, song, yonghong.song, jolsa, jiayuan.chen,
bpf, linux-kernel
struct_ops frees the global btf_vmlinux object.
In batch mode, a later struct_ops command can reuse stale state.
Reset the BTF pointer and cached map info state.
Fixes: 65c93628599d ("bpftool: Add struct_ops support")
Signed-off-by: Yichong Chen <chenyichong@uniontech.com>
---
tools/bpf/bpftool/struct_ops.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/tools/bpf/bpftool/struct_ops.c b/tools/bpf/bpftool/struct_ops.c
index aa43dead249c..835e5e561f7f 100644
--- a/tools/bpf/bpftool/struct_ops.c
+++ b/tools/bpf/bpftool/struct_ops.c
@@ -643,6 +643,10 @@ int do_struct_ops(int argc, char **argv)
err = cmd_select(cmds, argc, argv, do_help);
btf__free(btf_vmlinux);
+ btf_vmlinux = NULL;
+ map_info_type = NULL;
+ map_info_alloc_len = 0;
+ map_info_type_id = 0;
return err;
}
--
2.51.0
^ permalink raw reply related [flat|nested] 3+ messages in thread