From dfea2aa654243f70dc53b8648d0bbdeec55a7df1 Mon Sep 17 00:00:00 2001 From: Christoph Paasch Date: Thu, 18 Jun 2015 09:15:34 -0700 Subject: [PATCH] tcp: Do not call tcp_fastopen_reset_cipher from interrupt context 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] 00000000000004f2 ffff88007f8838a8 ffffffff8171d53a ffff880075a084a8 [ 36.009630] ffff880075a08000 ffff88007f8838c8 ffffffff810967d3 ffff88007f883928 [ 36.011076] 0000000000000000 ffff88007f8838f8 ffffffff81096892 ffff88007f89be00 [ 36.012494] Call Trace: [ 36.012953] [] dump_stack+0x4f/0x6d [ 36.014085] [] ___might_sleep+0x103/0x170 [ 36.015117] [] __might_sleep+0x52/0x90 [ 36.016117] [] kmem_cache_alloc_trace+0x47/0x190 [ 36.017266] [] ? tcp_fastopen_reset_cipher+0x42/0x130 [ 36.018485] [] tcp_fastopen_reset_cipher+0x42/0x130 [ 36.019679] [] tcp_fastopen_init_key_once+0x61/0x70 [ 36.020884] [] __tcp_fastopen_cookie_gen+0x1c/0x60 [ 36.022058] [] tcp_try_fastopen+0x58f/0x730 [ 36.023118] [] tcp_conn_request+0x3e8/0x7b0 [ 36.024185] [] ? __module_text_address+0x12/0x60 [ 36.025327] [] tcp_v4_conn_request+0x51/0x60 [ 36.026410] [] tcp_rcv_state_process+0x190/0xda0 [ 36.027556] [] ? __inet_lookup_established+0x47/0x170 [ 36.028784] [] tcp_v4_do_rcv+0x16d/0x3d0 [ 36.029832] [] ? security_sock_rcv_skb+0x16/0x20 [ 36.030936] [] tcp_v4_rcv+0x77a/0x7b0 [ 36.031875] [] ? iptable_filter_hook+0x33/0x70 [ 36.032953] [] ip_local_deliver_finish+0x92/0x1f0 [ 36.034065] [] ip_local_deliver+0x9a/0xb0 [ 36.035069] [] ? ip_rcv+0x3d0/0x3d0 [ 36.035963] [] ip_rcv_finish+0x119/0x330 [ 36.036950] [] ip_rcv+0x2e7/0x3d0 [ 36.037847] [] __netif_receive_skb_core+0x552/0x930 [ 36.038994] [] __netif_receive_skb+0x27/0x70 [ 36.040033] [] process_backlog+0xd2/0x1f0 [ 36.041025] [] net_rx_action+0x122/0x310 [ 36.042007] [] __do_softirq+0x103/0x2f0 [ 36.042978] [] 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 Cc: Hannes Frederic Sowa Fixes: 222e83d2e0ae ("tcp: switch tcp_fastopen key generation to net_get_random_once") Signed-off-by: Christoph Paasch Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- 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 46b087a27503..f9c0fb84e435 100644 --- a/net/ipv4/tcp_fastopen.c +++ b/net/ipv4/tcp_fastopen.c @@ -78,8 +78,6 @@ static bool __tcp_fastopen_cookie_gen(const void *path, struct tcp_fastopen_context *ctx; bool ok = false; - tcp_fastopen_init_key_once(true); - rcu_read_lock(); ctx = rcu_dereference(tcp_fastopen_ctx); if (ctx) { -- 2.20.1