From b9a395f0f7af66fe8224450481b99d4f83b57207 Mon Sep 17 00:00:00 2001 From: Geliang Tang Date: Thu, 8 Feb 2024 14:24:21 +0800 Subject: [PATCH 1/3] bpf, btf: Fix return value of register_btf_id_dtor_kfuncs The same as __register_btf_kfunc_id_set(), to let the modules with stripped btf section loaded, this patch changes the return value of register_btf_id_dtor_kfuncs() too from -ENOENT to 0 when btf is NULL. Signed-off-by: Geliang Tang Link: https://lore.kernel.org/r/eab65586d7fb0e72f2707d3747c7d4a5d60c823f.1707373307.git.tanggeliang@kylinos.cn Signed-off-by: Martin KaFai Lau --- kernel/bpf/btf.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index f7725cb6e564..16eb937eca46 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -8219,10 +8219,8 @@ int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_c pr_err("missing vmlinux BTF, cannot register dtor kfuncs\n"); return -ENOENT; } - if (owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) { - pr_err("missing module BTF, cannot register dtor kfuncs\n"); - return -ENOENT; - } + if (owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) + pr_warn("missing module BTF, cannot register dtor kfuncs\n"); return 0; } if (IS_ERR(btf)) From 9e60b0e02550aaf5f2301e49353641a5e3701674 Mon Sep 17 00:00:00 2001 From: Geliang Tang Date: Thu, 8 Feb 2024 14:24:22 +0800 Subject: [PATCH 2/3] bpf, btf: Add check_btf_kconfigs helper This patch extracts duplicate code on error path when btf_get_module_btf() returns NULL from the functions __register_btf_kfunc_id_set() and register_btf_id_dtor_kfuncs() into a new helper named check_btf_kconfigs() to check CONFIG_DEBUG_INFO_BTF and CONFIG_DEBUG_INFO_BTF_MODULES in it. Signed-off-by: Geliang Tang Acked-by: Jiri Olsa Link: https://lore.kernel.org/r/fa5537fc55f1e4d0bfd686598c81b7ab9dbd82b7.1707373307.git.tanggeliang@kylinos.cn Signed-off-by: Martin KaFai Lau --- kernel/bpf/btf.c | 33 +++++++++++++++------------------ 1 file changed, 15 insertions(+), 18 deletions(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 16eb937eca46..61e51cf0a995 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -7738,6 +7738,17 @@ static struct btf *btf_get_module_btf(const struct module *module) return btf; } +static int check_btf_kconfigs(const struct module *module, const char *feature) +{ + if (!module && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) { + pr_err("missing vmlinux BTF, cannot register %s\n", feature); + return -ENOENT; + } + if (module && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) + pr_warn("missing module BTF, cannot register %s\n", feature); + return 0; +} + BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags) { struct btf *btf = NULL; @@ -8098,15 +8109,8 @@ static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook, int ret, i; btf = btf_get_module_btf(kset->owner); - if (!btf) { - if (!kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) { - pr_err("missing vmlinux BTF, cannot register kfuncs\n"); - return -ENOENT; - } - if (kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) - pr_warn("missing module BTF, cannot register kfuncs\n"); - return 0; - } + if (!btf) + return check_btf_kconfigs(kset->owner, "kfunc"); if (IS_ERR(btf)) return PTR_ERR(btf); @@ -8214,15 +8218,8 @@ int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_c int ret; btf = btf_get_module_btf(owner); - if (!btf) { - if (!owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) { - pr_err("missing vmlinux BTF, cannot register dtor kfuncs\n"); - return -ENOENT; - } - if (owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) - pr_warn("missing module BTF, cannot register dtor kfuncs\n"); - return 0; - } + if (!btf) + return check_btf_kconfigs(owner, "dtor kfuncs"); if (IS_ERR(btf)) return PTR_ERR(btf); From 947e56f82fd783a1ec1c9359b20b5699d09cae14 Mon Sep 17 00:00:00 2001 From: Geliang Tang Date: Thu, 8 Feb 2024 14:24:23 +0800 Subject: [PATCH 3/3] bpf, btf: Check btf for register_bpf_struct_ops Similar to the handling in the functions __register_btf_kfunc_id_set() and register_btf_id_dtor_kfuncs(), this patch uses the newly added helper check_btf_kconfigs() to handle module with its btf section stripped. While at it, the patch also adds the missed IS_ERR() check to fix the commit f6be98d19985 ("bpf, net: switch to dynamic registration") Fixes: f6be98d19985 ("bpf, net: switch to dynamic registration") Signed-off-by: Geliang Tang Link: https://lore.kernel.org/r/69082b9835463fe36f9e354bddf2d0a97df39c2b.1707373307.git.tanggeliang@kylinos.cn Signed-off-by: Martin KaFai Lau --- kernel/bpf/btf.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 61e51cf0a995..8e06d29961f1 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -8882,7 +8882,9 @@ int __register_bpf_struct_ops(struct bpf_struct_ops *st_ops) btf = btf_get_module_btf(st_ops->owner); if (!btf) - return -EINVAL; + return check_btf_kconfigs(st_ops->owner, "struct_ops"); + if (IS_ERR(btf)) + return PTR_ERR(btf); log = kzalloc(sizeof(*log), GFP_KERNEL | __GFP_NOWARN); if (!log) {