From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Mon, 24 Jan 2011 22:41:20 +0000 (-0800)
Subject: tcp: fix bug in listening_get_next()
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=fd0273c5033630b8673554cd39660435d1ab2ac4;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

tcp: fix bug in listening_get_next()

commit a8b690f98baf9fb19 (tcp: Fix slowness in read /proc/net/tcp)
introduced a bug in handling of SYN_RECV sockets.

st->offset represents number of sockets found since beginning of
listening_hash[st->bucket].

We should not reset st->offset when iterating through
syn_table[st->sbucket], or else if more than ~25 sockets (if
PAGE_SIZE=4096) are in SYN_RECV state, we exit from listening_get_next()
with a too small st->offset

Next time we enter tcp_seek_last_pos(), we are not able to seek past
already found sockets.

Reported-by: PK <runningdoglackey@yahoo.com>
CC: Tom Herbert <therbert@google.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 856f68466d49..02f583b3744a 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1994,7 +1994,6 @@ static void *listening_get_next(struct seq_file *seq, void *cur)
 				}
 				req = req->dl_next;
 			}
-			st->offset = 0;
 			if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
 				break;
 get_req: