From: Eric Dumazet <edumazet@google.com> stable inclusion from stable-v4.19.256 commit e4a7b589cf19d20d587bc720ffbc55bad8ef26c6 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5Q0SQ CVE: NA -------------------------------- commit c4ee118561a0f74442439b7b5b486db1ac1ddfeb upstream. sk_forced_mem_schedule() has a bug similar to ones fixed in commit 7c80b038d23e ("net: fix sk_wmem_schedule() and sk_rmem_schedule() errors") While this bug has little chance to trigger in old kernels, we need to fix it before the following patch. Fixes: d83769a580f1 ("tcp: fix possible deadlock in tcp_send_fin()") Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Wei Wang <weiwan@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- net/ipv4/tcp_output.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index e1760b125b09..24e1f79e73d2 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3132,11 +3132,12 @@ void tcp_xmit_retransmit_queue(struct sock *sk) */ void sk_forced_mem_schedule(struct sock *sk, int size) { - int amt; + int delta, amt; - if (size <= sk->sk_forward_alloc) + delta = size - sk->sk_forward_alloc; + if (delta <= 0) return; - amt = sk_mem_pages(size); + amt = sk_mem_pages(delta); sk->sk_forward_alloc += amt * SK_MEM_QUANTUM; sk_memory_allocated_add(sk, amt); -- 2.25.1