Commit a7170d81 authored by Martin KaFai Lau's avatar Martin KaFai Lau
Browse files

Merge branch 'bpf, btf: Add DEBUG_INFO_BTF checks for __register_bpf_struct_ops' 



Geliang Tang says:

====================
bpf: Add DEBUG_INFO_BTF checks for __register_bpf_struct_ops

This patch set avoids module loading failure when the module
trying to register a struct_ops and the module has its btf section
stripped. This will then work similarly as module kfunc registration in
commit 3de4d22c ("bpf, btf: Warn but return no error for NULL btf from __register_btf_kfunc_id_set()")

v5:
 - drop CONFIG_MODULE_ALLOW_BTF_MISMATCH check as Martin suggested.

v4:
 - add a new patch to fix error checks for btf_get_module_btf.
 - rename the helper to check_btf_kconfigs.

v3:
 - fix this build error:
kernel/bpf/btf.c:7750:11: error: incomplete definition of type 'struct module'

Reported-by: default avatarkernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202402040934.Fph0XeEo-lkp@intel.com/



v2:
 - add register_check_missing_btf helper as Jiri suggested.
====================

Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
parents e55dad12 947e56f8

kernel/bpf/btf.c

+18 −21
Original line number Diff line number Diff line
@@ -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);
@@ -8214,17 +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_err("missing module BTF, cannot register dtor kfuncs\n");

			return -ENOENT;

		}

		return 0;

	}

	if (!btf)

		return check_btf_kconfigs(owner, "dtor kfuncs");

	if (IS_ERR(btf))

		return PTR_ERR(btf);
@@ -8887,7 +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) {