From acd886ac588a62356e6c92d9f8cedef42c50c883 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 14 Jun 2022 10:17:33 -0700 Subject: [PATCH] tcp: fix over estimation in sk_forced_mem_schedule() commit 3f29cbbc63de31c180110cd0e5ae15f5c28c1f95 upstream. sk_forced_mem_schedule() has a bug similar to ones fixed in commit 25f6b78d3bb7 ("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: e0454b507e43 ("tcp: fix possible deadlock in tcp_send_fin()") Signed-off-by: Eric Dumazet Acked-by: Soheil Hassas Yeganeh Reviewed-by: Shakeel Butt Reviewed-by: Wei Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- 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 fa7fb30e4b599..c37028af0db04 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3143,11 +3143,12 @@ 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); -- 2.39.5