From: Brandon Kammerdiener <brandon.kammerdiener@intel.com>
Date: Thu, 24 Apr 2025 15:32:51 +0000 (-0400)
Subject: bpf: fix possible endless loop in BPF map iteration
X-Git-Tag: v6.15-rc4~11^2~3^2~1
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=75673fda0c557ae26078177dd14d4857afbf128d;p=linux-2.6-block.git

bpf: fix possible endless loop in BPF map iteration

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>
---

diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 5a5adc66b8e2..92b606d60020 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -2189,7 +2189,7 @@ static long bpf_for_each_hash_elem(struct bpf_map *map, bpf_callback_t callback_
 		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 */