From: Andrii Nakryiko <andriin@fb.com>
To: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>, <ast@fb.com>,
<daniel@iogearbox.net>
Cc: <andrii.nakryiko@gmail.com>, <kernel-team@fb.com>,
Andrii Nakryiko <andriin@fb.com>,
Song Liu <songliubraving@fb.com>, <stable@vger.kernel.org>
Subject: [PATCH v3 bpf 1/2] bpf: fix map leak in HASH_OF_MAPS map
Date: Mon, 27 Jul 2020 17:31:37 -0700 [thread overview]
Message-ID: <20200728003139.2410375-1-andriin@fb.com> (raw)
Fix HASH_OF_MAPS bug of not putting inner map pointer on bpf_map_elem_update()
operation. This is due to per-cpu extra_elems optimization, which bypassed
free_htab_elem() logic doing proper clean ups. Make sure that inner map is put
properly in optimized case as well.
Fixes: 8c290e60fa2a ("bpf: fix hashmap extra_elems logic")
Acked-by: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org> # v4.14+
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
kernel/bpf/hashtab.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index b4b288a3c3c9..b32cc8ce8ff6 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -779,15 +779,20 @@ static void htab_elem_free_rcu(struct rcu_head *head)
htab_elem_free(htab, l);
}
-static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
+static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l)
{
struct bpf_map *map = &htab->map;
+ void *ptr;
if (map->ops->map_fd_put_ptr) {
- void *ptr = fd_htab_map_get_ptr(map, l);
-
+ ptr = fd_htab_map_get_ptr(map, l);
map->ops->map_fd_put_ptr(ptr);
}
+}
+
+static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
+{
+ htab_put_fd_value(htab, l);
if (htab_is_prealloc(htab)) {
__pcpu_freelist_push(&htab->freelist, &l->fnode);
@@ -839,6 +844,7 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
*/
pl_new = this_cpu_ptr(htab->extra_elems);
l_new = *pl_new;
+ htab_put_fd_value(htab, old_elem);
*pl_new = old_elem;
} else {
struct pcpu_freelist_node *l;
--
2.24.1
next reply other threads:[~2020-07-28 0:31 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-28 0:31 Andrii Nakryiko [this message]
2020-07-28 0:31 ` [PATCH v3 bpf 2/2] selftests/bpf: extend map-in-map selftest to detect memory leaks Andrii Nakryiko
2020-07-28 20:54 ` Song Liu
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