From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Date: Thu, 17 Mar 2022 17:29:51 +0530
Subject: bpf: Always raise reference in btf_get_module_btf
Patch-mainline: v5.18-rc1
Git-commit: 9492450fd28736262dea9143ebb3afc2c131ace1
References: jsc#PED-1377
Align it with helpers like bpf_find_btf_id, so all functions returning
BTF in out parameter follow the same rule of raising reference
consistently, regardless of module or vmlinux BTF.
Adjust existing callers to handle the change accordinly.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220317115957.3193097-10-memxor@gmail.com
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
kernel/bpf/btf.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -6572,20 +6572,23 @@ struct module *btf_try_get_module(const
return res;
}
-/* Returns struct btf corresponding to the struct module
- *
- * This function can return NULL or ERR_PTR. Note that caller must
- * release reference for struct btf iff btf_is_module is true.
+/* Returns struct btf corresponding to the struct module.
+ * This function can return NULL or ERR_PTR.
*/
static struct btf *btf_get_module_btf(const struct module *module)
{
- struct btf *btf = NULL;
#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
struct btf_module *btf_mod, *tmp;
#endif
+ struct btf *btf = NULL;
+
+ if (!module) {
+ btf = bpf_get_btf_vmlinux();
+ if (!IS_ERR(btf))
+ btf_get(btf);
+ return btf;
+ }
- if (!module)
- return bpf_get_btf_vmlinux();
#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
mutex_lock(&btf_module_mutex);
list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
@@ -6823,9 +6826,7 @@ int register_btf_kfunc_id_set(enum bpf_p
hook = bpf_prog_type_to_kfunc_hook(prog_type);
ret = btf_populate_kfunc_set(btf, hook, kset);
- /* reference is only taken for module BTF */
- if (btf_is_module(btf))
- btf_put(btf);
+ btf_put(btf);
return ret;
}
EXPORT_SYMBOL_GPL(register_btf_kfunc_id_set);