6.12-stable review patch. If anyone has any objections, please let me know.
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From: Mykyta Yatsenko yatsenko@meta.com
[ Upstream commit d0445d7dd3fd9b15af7564c38d7aa3cbc29778ee ]
Avoid dereferencing bpf_map_skeleton's link field if it's NULL. If BPF map skeleton is created with the size, that indicates containing link field, but the field was not actually initialized with valid bpf_link pointer, libbpf crashes. This may happen when using libbpf-rs skeleton. Skeleton loading may still progress, but user needs to attach struct_ops map separately.
Signed-off-by: Mykyta Yatsenko yatsenko@meta.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20250514113220.219095-1-mykyta.yatsenko5@gmail.c... Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/libbpf.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index bb24f6bac2073..1290314da6761 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -13971,6 +13971,12 @@ int bpf_object__attach_skeleton(struct bpf_object_skeleton *s) }
link = map_skel->link; + if (!link) { + pr_warn("map '%s': BPF map skeleton link is uninitialized\n", + bpf_map__name(map)); + continue; + } + if (*link) continue;