tcp_fastopen_reset_cipher really cannot be called from interrupt
context. It allocates the tcp_fastopen_context with GFP_KERNEL and
calls crypto_alloc_cipher, which allocates all kind of stuff with
GFP_KERNEL.
Thus, we might sleep when the key-generation is triggered by an
incoming TFO cookie-request which would then happen in interrupt-
context, as shown by enabling CONFIG_DEBUG_ATOMIC_SLEEP:
[ 36.001813] BUG: sleeping function called from invalid context at
mm/slub.c:1266
[ 36.003624] in_atomic(): 1, irqs_disabled(): 0, pid: 1016, name: packetdrill
[ 36.004859] CPU: 1 PID: 1016 Comm: packetdrill Not tainted 4.1.0-rc7 #14
[ 36.006085] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
[ 36.008250] 04f2 88007f8838a8 8171d53a
880075a084a8
[ 36.009630] 880075a08000 88007f8838c8 810967d3
88007f883928
[ 36.011076] 88007f8838f8 81096892
88007f89be00
[ 36.012494] Call Trace:
[ 36.012953] IRQ [8171d53a] dump_stack+0x4f/0x6d
[ 36.014085] [810967d3] ___might_sleep+0x103/0x170
[ 36.015117] [81096892] __might_sleep+0x52/0x90
[ 36.016117] [8118e887] kmem_cache_alloc_trace+0x47/0x190
[ 36.017266] [81680d82] ? tcp_fastopen_reset_cipher+0x42/0x130
[ 36.018485] [81680d82] tcp_fastopen_reset_cipher+0x42/0x130
[ 36.019679] [81680f01] tcp_fastopen_init_key_once+0x61/0x70
[ 36.020884] [81680f2c] __tcp_fastopen_cookie_gen+0x1c/0x60
[ 36.022058] [816814ff] tcp_try_fastopen+0x58f/0x730
[ 36.023118] [81671788] tcp_conn_request+0x3e8/0x7b0
[ 36.024185] [810e3872] ? __module_text_address+0x12/0x60
[ 36.025327] [8167b2e1] tcp_v4_conn_request+0x51/0x60
[ 36.026410] [816727e0] tcp_rcv_state_process+0x190/0xda0
[ 36.027556] [81661f97] ? __inet_lookup_established+0x47/0x170
[ 36.028784] [8167c2ad] tcp_v4_do_rcv+0x16d/0x3d0
[ 36.029832] [812e6806] ? security_sock_rcv_skb+0x16/0x20
[ 36.030936] [8167cc8a] tcp_v4_rcv+0x77a/0x7b0
[ 36.031875] [816af8c3] ? iptable_filter_hook+0x33/0x70
[ 36.032953] [81657d22] ip_local_deliver_finish+0x92/0x1f0
[ 36.034065] [81657f1a] ip_local_deliver+0x9a/0xb0
[ 36.035069] [81657c90] ? ip_rcv+0x3d0/0x3d0
[ 36.035963] [81657569] ip_rcv_finish+0x119/0x330
[ 36.036950] [81657ba7] ip_rcv+0x2e7/0x3d0
[ 36.037847] [81610652] __netif_receive_skb_core+0x552/0x930
[ 36.038994] [81610a57] __netif_receive_skb+0x27/0x70
[ 36.040033] [81610b72] process_backlog+0xd2/0x1f0
[ 36.041025] [81611482] net_rx_action+0x122/0x310
[ 36.042007] [81076743] __do_softirq+0x103/0x2f0
[ 36.042978] [81723e3c] do_softirq_own_stack+0x1c/0x30
This patch moves the call to tcp_fastopen_init_key_once to the places
where a listener socket creates its TFO-state, which always happens in
user-context (either from the setsockopt, or implicitly during the
listen()-call)
Cc: Eric Dumazet eric.duma...@gmail.com
Cc: Hannes Frederic Sowa han...@stressinduktion.org
Fixes: 222e83d2e0ae (tcp: switch tcp_fastopen key generation to
net_get_random_once)
Signed-off-by: Christoph Paasch cpaa...@apple.com
---
Notes:
v2: Instead of reverting Hannes' patch, move the call to
tcp_fastopen_init_once
to the places where we enable TFO on the server-side from user-context.
net/ipv4/af_inet.c | 2 ++
net/ipv4/tcp.c | 7 +--
net/ipv4/tcp_fastopen.c | 2 --
3 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 8b47a4d79d04..a5aa54ea6533 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -228,6 +228,8 @@ int inet_listen(struct socket *sock, int backlog)
err = 0;
if (err)
goto out;
+
+ tcp_fastopen_init_key_once(true);
}
err = inet_csk_listen_start(sk, backlog);
if (err)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index f1377f2a0472..bb2ce74f6004 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2545,10 +2545,13 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
case TCP_FASTOPEN:
if (val = 0 ((1 sk-sk_state) (TCPF_CLOSE |
- TCPF_LISTEN)))
+ TCPF_LISTEN))) {
+ tcp_fastopen_init_key_once(true);
+
err = fastopen_init_queue(sk, val);
- else
+ } else {
err = -EINVAL;
+ }
break;
case TCP_TIMESTAMP:
if (!tp-repair)
diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index
