bpf: fix possible endless loop in BPF map iteration

[ Upstream commit 75673fda0c557ae26078177dd14d4857afbf128d ]

The _safe variant used here gets the next element before running the callback,
avoiding the endless loop condition.

Signed-off-by: Brandon Kammerdiener <brandon.kammerdiener@intel.com>
Link: https://lore.kernel.org/r/20250424153246.141677-2-brandon.kammerdiener@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index d08fe64e0e453ac13effb34b0dd3e7fb5d169397..24258c54057d46fdd3b2f724860e795f2011cb99 100644 (file)
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -2102,7 +2102,7 @@ static int bpf_for_each_hash_elem(struct bpf_map *map, void *callback_fn,
                b = &htab->buckets[i];
                rcu_read_lock();
                head = &b->head;
-               hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
+               hlist_nulls_for_each_entry_safe(elem, n, head, hash_node) {
                        key = elem->key;
                        if (is_percpu) {
                                /* current cpu value for percpu map */