From: thinker.li@gmail.com
To: bpf@vger.kernel.org, ast@kernel.org, martin.lau@linux.dev,
song@kernel.org, kernel-team@meta.com, andrii@kernel.org,
drosen@google.com
Cc: sinquersw@gmail.com, kuifeng@meta.com,
Kui-Feng Lee <thinker.li@gmail.com>
Subject: [PATCH bpf-next v5 3/9] bpf: hold module for bpf_struct_ops_map.
Date: Tue, 17 Oct 2023 09:23:00 -0700 [thread overview]
Message-ID: <20231017162306.176586-4-thinker.li@gmail.com> (raw)
In-Reply-To: <20231017162306.176586-1-thinker.li@gmail.com>
From: Kui-Feng Lee <thinker.li@gmail.com>
To ensure that a module remains accessible whenever a struct_ops object of
a struct_ops type provided by the module is still in use.
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
---
include/linux/bpf.h | 1 +
kernel/bpf/bpf_struct_ops.c | 21 ++++++++++++++++++---
2 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index e6a648af2daa..1e1647c8b0ce 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1627,6 +1627,7 @@ struct bpf_struct_ops {
int (*update)(void *kdata, void *old_kdata);
int (*validate)(void *kdata);
struct btf *btf;
+ struct module *owner;
const struct btf_type *type;
const struct btf_type *value_type;
const char *name;
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index 7758f66ad734..b561245fe235 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -112,6 +112,7 @@ static const struct btf_type *module_type;
static void bpf_struct_ops_init_one(struct bpf_struct_ops *st_ops,
struct btf *btf,
+ struct module *owner,
struct bpf_verifier_log *log)
{
const struct btf_member *member;
@@ -186,6 +187,7 @@ static void bpf_struct_ops_init_one(struct bpf_struct_ops *st_ops,
st_ops->name);
} else {
st_ops->btf = btf;
+ st_ops->owner = owner;
st_ops->type_id = type_id;
st_ops->type = t;
st_ops->value_id = value_id;
@@ -193,6 +195,7 @@ static void bpf_struct_ops_init_one(struct bpf_struct_ops *st_ops,
value_id);
}
}
+
}
void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log)
@@ -215,7 +218,7 @@ void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log)
for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
st_ops = bpf_struct_ops[i];
- bpf_struct_ops_init_one(st_ops, btf, log);
+ bpf_struct_ops_init_one(st_ops, btf, NULL, log);
}
}
@@ -630,6 +633,7 @@ static void __bpf_struct_ops_map_free(struct bpf_map *map)
bpf_jit_uncharge_modmem(PAGE_SIZE);
}
bpf_map_area_free(st_map->uvalue);
+ module_put(st_map->st_ops->owner);
bpf_map_area_free(st_map);
}
@@ -676,9 +680,18 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr)
if (!st_ops)
return ERR_PTR(-ENOTSUPP);
+ /* If st_ops->owner is NULL, it means the struct_ops is
+ * statically defined in the kernel. We don't need to
+ * take a refcount on it.
+ */
+ if (st_ops->owner && !btf_try_get_module(st_ops->btf))
+ return ERR_PTR(-EINVAL);
+
vt = st_ops->value_type;
- if (attr->value_size != vt->size)
+ if (attr->value_size != vt->size) {
+ module_put(st_ops->owner);
return ERR_PTR(-EINVAL);
+ }
t = st_ops->type;
@@ -689,8 +702,10 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr)
(vt->size - sizeof(struct bpf_struct_ops_value));
st_map = bpf_map_area_alloc(st_map_size, NUMA_NO_NODE);
- if (!st_map)
+ if (!st_map) {
+ module_put(st_ops->owner);
return ERR_PTR(-ENOMEM);
+ }
st_map->st_ops = st_ops;
map = &st_map->map;
--
2.34.1
next prev parent reply other threads:[~2023-10-17 16:23 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-17 16:22 [PATCH bpf-next v5 0/9] Registrating struct_ops types from modules thinker.li
2023-10-17 16:22 ` [PATCH bpf-next v5 1/9] bpf: refactory struct_ops type initialization to a function thinker.li
2023-10-17 16:22 ` [PATCH bpf-next v5 2/9] bpf: add struct_ops_tab to btf thinker.li
2023-10-19 0:00 ` Martin KaFai Lau
2023-10-19 0:33 ` Kui-Feng Lee
2023-10-19 2:28 ` Martin KaFai Lau
2023-10-19 16:15 ` Kui-Feng Lee
2023-10-17 16:23 ` thinker.li [this message]
2023-10-19 0:36 ` [PATCH bpf-next v5 3/9] bpf: hold module for bpf_struct_ops_map Martin KaFai Lau
2023-10-19 16:29 ` Kui-Feng Lee
2023-10-20 5:07 ` Kui-Feng Lee
2023-10-20 21:37 ` Martin KaFai Lau
2023-10-20 22:28 ` Kui-Feng Lee
2023-10-17 16:23 ` [PATCH bpf-next v5 4/9] bpf: validate value_type thinker.li
2023-10-17 16:23 ` [PATCH bpf-next v5 5/9] bpf: pass attached BTF to the bpf_struct_ops subsystem thinker.li
2023-10-17 16:23 ` [PATCH bpf-next v5 6/9] bpf, net: switch to dynamic registration thinker.li
2023-10-19 1:49 ` Martin KaFai Lau
2023-10-20 15:12 ` Kui-Feng Lee
2023-10-20 17:53 ` Kui-Feng Lee
2023-10-17 16:23 ` [PATCH bpf-next v5 7/9] libbpf: Find correct module BTFs for struct_ops maps and progs thinker.li
2023-10-17 21:49 ` Andrii Nakryiko
2023-10-18 2:25 ` Kui-Feng Lee
2023-10-19 2:43 ` Martin KaFai Lau
2023-10-19 16:31 ` Kui-Feng Lee
2023-10-17 16:23 ` [PATCH bpf-next v5 8/9] bpf: export btf_ctx_access to modules thinker.li
2023-10-17 16:23 ` [PATCH bpf-next v5 9/9] selftests/bpf: test case for register_bpf_struct_ops() thinker.li
2023-10-17 18:03 ` kernel test robot
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