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: v5.15.185~201
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=af8a8fce197b646da61129848a263579f05efa72;p=thirdparty%2Fkernel%2Fstable.git

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 d08fe64e0e453..24258c54057d4 100644
--- 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 */