diff options
| author | Yonghong Song <yhs@fb.com> | 2018-01-22 22:53:51 -0800 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-01-23 17:33:57 +0100 |
| commit | 2310035fa03f651dd5b03f19a26a97512aa8842c (patch) | |
| tree | 8758454fd5163b0ede4fa9a925b797d9e67d30aa | |
| parent | e8a22b5f079449f1803d37ce2b5d09acaa68368d (diff) | |
| download | linux-2310035fa03f651dd5b03f19a26a97512aa8842c.tar.bz2 | |
bpf: fix incorrect kmalloc usage in lpm_trie MAP_GET_NEXT_KEY rcu region
In commit b471f2f1de8b ("bpf: implement MAP_GET_NEXT_KEY command for LPM_TRIE map"),
the implemented MAP_GET_NEXT_KEY callback function is guarded with rcu read lock.
In the function body, "kmalloc(size, GFP_USER | __GFP_NOWARN)" is used which may
sleep and violate rcu read lock region requirements. This patch fixed the issue
by using GFP_ATOMIC instead to avoid blocking kmalloc. Tested with
CONFIG_DEBUG_ATOMIC_SLEEP=y as suggested by Eric Dumazet.
Fixes: b471f2f1de8b ("bpf: implement MAP_GET_NEXT_KEY command for LPM_TRIE map")
Signed-off-by: Yonghong Song <yhs@fb.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
| -rw-r--r-- | kernel/bpf/lpm_trie.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c index d7ea96218516..8f083ea9d4b9 100644 --- a/kernel/bpf/lpm_trie.c +++ b/kernel/bpf/lpm_trie.c @@ -624,7 +624,7 @@ static int trie_get_next_key(struct bpf_map *map, void *_key, void *_next_key) } node_stack = kmalloc(trie->max_prefixlen * sizeof(struct lpm_trie_node *), - GFP_USER | __GFP_NOWARN); + GFP_ATOMIC | __GFP_NOWARN); if (!node_stack) return -ENOMEM; |