From a5a7b25d7535ce5d8db0c121ef588bc6ca3a39dc Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Fri, 27 Jun 2025 10:53:09 -0700 Subject: [PATCH] bpf: guard BTF_ID_FLAGS(bpf_cgroup_read_xattr) with CONFIG_BPF_LSM Function bpf_cgroup_read_xattr is defined in fs/bpf_fs_kfuncs.c, which is compiled only when CONFIG_BPF_LSM is set. Add CONFIG_BPF_LSM check to bpf_cgroup_read_xattr spec in common_btf_ids in kernel/bpf/helpers.c to avoid build failures for configs w/o CONFIG_BPF_LSM. Build failure example: BTF .tmp_vmlinux1.btf.o btf_encoder__tag_kfunc: failed to find kfunc 'bpf_cgroup_read_xattr' in BTF ... WARN: resolve_btfids: unresolved symbol bpf_cgroup_read_xattr make[2]: *** [scripts/Makefile.vmlinux:91: vmlinux.unstripped] Error 255 Fixes: 535b070f4a80 ("bpf: Introduce bpf_cgroup_read_xattr to read xattr of cgroup's node") Reported-by: Jake Hillion Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/r/20250627175309.2710973-1-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/helpers.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index b4117681137e..f48fa3fe8dec 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -3779,7 +3779,7 @@ BTF_ID_FLAGS(func, bpf_strspn); BTF_ID_FLAGS(func, bpf_strcspn); BTF_ID_FLAGS(func, bpf_strstr); BTF_ID_FLAGS(func, bpf_strnstr); -#ifdef CONFIG_CGROUPS +#if defined(CONFIG_BPF_LSM) && defined(CONFIG_CGROUPS) BTF_ID_FLAGS(func, bpf_cgroup_read_xattr, KF_RCU) #endif BTF_KFUNCS_END(common_btf_ids) -- 2.47.2