Commit 195114a5 authored Apr 14, 2018 by Soheil Hassas Yeganeh Committed by Subash Abhinov Kasiviswanathan Apr 15, 2018

tcp: clear tp->packets_out when purging write queue



Clear tp->packets_out when purging the write queue, otherwise
tcp_rearm_rto() mistakenly assumes TCP write queue is not empty.
This results in NULL pointer dereference.

Also, remove the redundant `tp->packets_out = 0` from
tcp_disconnect(), since tcp_disconnect() calls
tcp_write_queue_purge().

CRs-Fixed: 2224545
Change-Id: I26f00abdd7fcfc6cdb30d89811ccf7be90f8186f
Fixes: a27fd7a8ed38 (tcp: purge write queue upon RST)
Reported-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Reported-by: Sami Farin <hvtaifwkbgefbaei@gmail.com>
Tested-by: Sami Farin <hvtaifwkbgefbaei@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Patch-mainline: netdev @ April 15, 2018, 12:45 a.m.
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>

parent 452becbf

include/net/tcp.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -1617,6 +1617,7 @@ static inline void tcp_write_queue_purge(struct sock *sk)
		sk_mem_reclaim(sk);
		tcp_clear_all_retrans_hints(tcp_sk(sk));
		tcp_init_send_head(sk);
		tcp_sk(sk)->packets_out = 0;
		}

		static inline struct sk_buff tcp_write_queue_head(const struct sock sk)

net/ipv4/tcp.c

+0 −1

Original line number	Diff line number	Diff line
		@@ -2354,7 +2354,6 @@ int tcp_disconnect(struct sock *sk, int flags)
		icsk->icsk_backoff = 0;
		tp->snd_cwnd = 2;
		icsk->icsk_probes_out = 0;
		tp->packets_out = 0;
		tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
		tp->snd_cwnd_cnt = 0;
		tp->window_clamp = 0;