From: Dave Marchevsky <davemarchevsky@fb.com>
To: <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Kernel Team <kernel-team@fb.com>, Tejun Heo <tj@kernel.org>,
Dave Marchevsky <davemarchevsky@fb.com>
Subject: [RFC PATCH bpf-next 07/11] bpf: Enforce spinlock hold for bpf_rbtree_{add,remove,find}
Date: Fri, 22 Jul 2022 11:34:34 -0700 [thread overview]
Message-ID: <20220722183438.3319790-8-davemarchevsky@fb.com> (raw)
In-Reply-To: <20220722183438.3319790-1-davemarchevsky@fb.com>
The bpf program calling these helpers must hold the spinlock associated
with the rbtree map when doing so. Otherwise, a concurrent add/remove
operation could corrupt the tree while {add,remove,find} are walking it
with callback or pivoting after update.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
---
kernel/bpf/rbtree.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/kernel/bpf/rbtree.c b/kernel/bpf/rbtree.c
index bf2e30af82ec..5b1ab73e164f 100644
--- a/kernel/bpf/rbtree.c
+++ b/kernel/bpf/rbtree.c
@@ -14,6 +14,11 @@ struct bpf_rbtree {
BTF_ID_LIST_SINGLE(bpf_rbtree_btf_ids, struct, rb_node);
+static bool __rbtree_lock_held(struct bpf_rbtree *tree)
+{
+ return spin_is_locked((spinlock_t *)tree->lock);
+}
+
static int rbtree_map_alloc_check(union bpf_attr *attr)
{
if (attr->max_entries || !attr->btf_value_type_id)
@@ -93,6 +98,9 @@ BPF_CALL_3(bpf_rbtree_add, struct bpf_map *, map, void *, value, void *, cb)
struct bpf_rbtree *tree = container_of(map, struct bpf_rbtree, map);
struct rb_node *node = (struct rb_node *)value;
+ if (!__rbtree_lock_held(tree))
+ return (u64)NULL;
+
if (WARN_ON_ONCE(!RB_EMPTY_NODE(node)))
return (u64)NULL;
@@ -114,6 +122,9 @@ BPF_CALL_3(bpf_rbtree_find, struct bpf_map *, map, void *, key, void *, cb)
{
struct bpf_rbtree *tree = container_of(map, struct bpf_rbtree, map);
+ if (!__rbtree_lock_held(tree))
+ return (u64)NULL;
+
return (u64)rb_find(key, &tree->root.rb_root,
(int (*)(const void *key,
const struct rb_node *))cb);
@@ -206,6 +217,9 @@ BPF_CALL_2(bpf_rbtree_remove, struct bpf_map *, map, void *, value)
struct bpf_rbtree *tree = container_of(map, struct bpf_rbtree, map);
struct rb_node *node = (struct rb_node *)value;
+ if (!__rbtree_lock_held(tree))
+ return (u64)NULL;
+
if (WARN_ON_ONCE(RB_EMPTY_NODE(node)))
return (u64)NULL;
--
2.30.2
next prev parent reply other threads:[~2022-07-22 18:35 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-22 18:34 [RFC PATCH bpf-next 00/11] bpf: Introduce rbtree map Dave Marchevsky
2022-07-22 18:34 ` [RFC PATCH bpf-next 01/11] bpf: Pull repeated reg access bounds check into helper fn Dave Marchevsky
2022-07-22 18:34 ` [RFC PATCH bpf-next 02/11] bpf: Add verifier support for custom callback return range Dave Marchevsky
2022-07-22 18:34 ` [RFC PATCH bpf-next 03/11] bpf: Add rb_node_off to bpf_map Dave Marchevsky
2022-08-01 22:19 ` Alexei Starovoitov
2022-07-22 18:34 ` [RFC PATCH bpf-next 04/11] bpf: Add rbtree map Dave Marchevsky
2022-08-01 21:49 ` Alexei Starovoitov
2022-07-22 18:34 ` [RFC PATCH bpf-next 05/11] bpf: Add bpf_spin_lock member to rbtree Dave Marchevsky
2022-08-01 22:17 ` Alexei Starovoitov
2022-08-02 13:59 ` Kumar Kartikeya Dwivedi
2022-08-02 15:30 ` Alexei Starovoitov
2022-08-10 21:46 ` Kumar Kartikeya Dwivedi
2022-08-10 22:06 ` Alexei Starovoitov
2022-08-10 23:16 ` Kumar Kartikeya Dwivedi
2022-08-15 5:33 ` Yonghong Song
2022-08-15 5:37 ` Kumar Kartikeya Dwivedi
2022-07-22 18:34 ` [RFC PATCH bpf-next 06/11] bpf: Add bpf_rbtree_{lock,unlock} helpers Dave Marchevsky
2022-08-01 21:58 ` Alexei Starovoitov
2022-07-22 18:34 ` Dave Marchevsky [this message]
2022-07-22 18:34 ` [RFC PATCH bpf-next 08/11] bpf: Add OBJ_NON_OWNING_REF type flag Dave Marchevsky
2022-08-01 22:41 ` Alexei Starovoitov
2022-07-22 18:34 ` [RFC PATCH bpf-next 09/11] bpf: Add CONDITIONAL_RELEASE " Dave Marchevsky
2022-08-01 22:23 ` Alexei Starovoitov
2022-07-22 18:34 ` [RFC PATCH bpf-next 10/11] bpf: Introduce PTR_ITER and PTR_ITER_END type flags Dave Marchevsky
2022-07-29 16:31 ` Tejun Heo
2022-08-01 22:44 ` Alexei Starovoitov
2022-08-02 13:05 ` Kumar Kartikeya Dwivedi
2022-08-02 15:10 ` Alexei Starovoitov
2022-08-10 17:56 ` Dave Marchevsky
2022-07-22 18:34 ` [RFC PATCH bpf-next 11/11] selftests/bpf: Add rbtree map tests Dave Marchevsky
2022-07-28 7:18 ` Yonghong Song
2022-08-10 17:48 ` Dave Marchevsky
2022-07-28 7:04 ` [RFC PATCH bpf-next 00/11] bpf: Introduce rbtree map Yonghong Song
2022-08-10 17:54 ` Dave Marchevsky
2022-08-01 21:27 ` Alexei Starovoitov
2022-08-10 18:11 ` Dave Marchevsky
2022-08-02 22:02 ` Andrii Nakryiko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220722183438.3319790-8-davemarchevsky@fb.com \
--to=davemarchevsky@fb.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=kernel-team@fb.com \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).