This is a note to let you know that I've just added the patch titled ipv4: Fix a data-race around sysctl_fib_sync_mem. to the 5.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ipv4-fix-a-data-race-around-sysctl_fib_sync_mem.patch and it can be found in the queue-5.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 858c0a3b1b6486a5dd1aaea23ad50bb06556b84a Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Date: Wed Jul 6 16:40:03 2022 -0700 ipv4: Fix a data-race around sysctl_fib_sync_mem. [ Upstream commit 73318c4b7dbd0e781aaababff17376b2894745c0 ] While reading sysctl_fib_sync_mem, it can be changed concurrently. So, we need to add READ_ONCE() to avoid a data-race. Fixes: 9ab948a91b2c ("ipv4: Allow amount of dirty memory from fib resizing to be controllable") Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c index fb0e49c36c2e..43a496272227 100644 --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -498,7 +498,7 @@ static void tnode_free(struct key_vector *tn) tn = container_of(head, struct tnode, rcu)->kv; } - if (tnode_free_size >= sysctl_fib_sync_mem) { + if (tnode_free_size >= READ_ONCE(sysctl_fib_sync_mem)) { tnode_free_size = 0; synchronize_rcu(); }