Re: [PATCH net-next v25 10/13] net: add SO_DEVMEM_DONTNEED setsockopt to release RX frags

On Thu, 10 Oct 2024 12:05:38 -0700 Mina Almasry wrote:

diff --git a/net/core/sock.c b/net/core/sock.c index 083d438d8b6f..cb3d8b19de14 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1071,11 +1071,11 @@ sock_devmem_dontneed(struct sock *sk, sockptr_t optval, unsigned int optlen) optlen > sizeof(*tokens) * MAX_DONTNEED_TOKENS) return -EINVAL;

•   tokens = kvmalloc_array(optlen, sizeof(*tokens), GFP_KERNEL);
  

•   num_tokens = optlen / sizeof(struct dmabuf_token);
  

•   tokens = kvmalloc_array(num_tokens, sizeof(*tokens), GFP_KERNEL);
    if (!tokens)
            return -ENOMEM;
  
  

•   num_tokens = optlen / sizeof(struct dmabuf_token);
    if (copy_from_sockptr(tokens, optval, optlen)) {
            kvfree(tokens);
            return -EFAULT;
  

@@ -1083,6 +1083,10 @@ sock_devmem_dontneed(struct sock *sk, sockptr_t optval, unsigned int optlen)

    xa_lock_bh(&sk->sk_user_frags);
    for (i = 0; i < num_tokens; i++) {

•           if (tokens[i].token_count > MAX_DONTNEED_TOKENS)
  

•                   continue;
  

For the real fix let's scan the tokens before we take the xa lock and return an error rather than silently skipping?

            for (j = 0; j < tokens[i].token_count; j++) {