3.6.11.1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 74b2a7b4ea60d5c1c94ac01ad001e16ac40132f3 ]
commit 02275a2ee7c0 (tcp: don't abort splice() after small transfers)
added a regression.
[ 83.843570] INFO: rcu_sched self-detected stall on CPU
[ 83.844575] INFO: rcu_sched detected stalls on CPUs/tasks: { 6} (detected by 0, t=21002 jiffies, g=4457, c=4456, q=13132)
[ 83.844582] Task dump for CPU 6:
[ 83.844584] netperf R running task 0 8966 8952 0x0000000c
[ 83.844587] 0000000000000000 0000000000000006 0000000000006c6c 0000000000000000
[ 83.844589] 000000000000006c 0000000000000096 ffffffff819ce2bc ffffffffffffff10
[ 83.844592] ffffffff81088679 0000000000000010 0000000000000246 ffff880c4b9ddcd8
[ 83.844594] Call Trace:
[ 83.844596] [<ffffffff81088679>] ? vprintk_emit+0x1c9/0x4c0
[ 83.844601] [<ffffffff815ad449>] ? schedule+0x29/0x70
[ 83.844606] [<ffffffff81537bd2>] ? tcp_splice_data_recv+0x42/0x50
[ 83.844610] [<ffffffff8153beaa>] ? tcp_read_sock+0xda/0x260
[ 83.844613] [<ffffffff81537b90>] ? tcp_prequeue_process+0xb0/0xb0
[ 83.844615] [<ffffffff8153c0f0>] ? tcp_splice_read+0xc0/0x250
[ 83.844618] [<ffffffff814dc0c2>] ? sock_splice_read+0x22/0x30
[ 83.844622] [<ffffffff811b820b>] ? do_splice_to+0x7b/0xa0
[ 83.844627] [<ffffffff811ba4bc>] ? sys_splice+0x59c/0x5d0
[ 83.844630] [<ffffffff8119745b>] ? putname+0x2b/0x40
[ 83.844633] [<ffffffff8118bcb4>] ? do_sys_open+0x174/0x1e0
[ 83.844636] [<ffffffff815b6202>] ? system_call_fastpath+0x16/0x1b
if recv_actor() returns 0, we should stop immediately,
because looping wont give a chance to drain the pipe.
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Willy Tarreau <w@xxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
---
net/ipv4/tcp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 5fe7a59..8720b83 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1508,7 +1508,7 @@ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
break;
}
used = recv_actor(desc, skb, offset, len);
- if (used < 0) {
+ if (used <= 0) {
if (!copied)
copied = used;
break;
--
1.7.10.4
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