Commits
Christoph Paasch committed dfea2aa6542
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] <IRQ> [<ffffffff8171d53a>] dump_stack+0x4f/0x6d
[ 36.014085] [<ffffffff810967d3>] ___might_sleep+0x103/0x170
[ 36.015117] [<ffffffff81096892>] __might_sleep+0x52/0x90
[ 36.016117] [<ffffffff8118e887>] kmem_cache_alloc_trace+0x47/0x190
[ 36.017266] [<ffffffff81680d82>] ? tcp_fastopen_reset_cipher+0x42/0x130
[ 36.018485] [<ffffffff81680d82>] tcp_fastopen_reset_cipher+0x42/0x130
[ 36.019679] [<ffffffff81680f01>] tcp_fastopen_init_key_once+0x61/0x70
[ 36.020884] [<ffffffff81680f2c>] __tcp_fastopen_cookie_gen+0x1c/0x60
[ 36.022058] [<ffffffff816814ff>] tcp_try_fastopen+0x58f/0x730
[ 36.023118] [<ffffffff81671788>] tcp_conn_request+0x3e8/0x7b0
[ 36.024185] [<ffffffff810e3872>] ? __module_text_address+0x12/0x60
[ 36.025327] [<ffffffff8167b2e1>] tcp_v4_conn_request+0x51/0x60
[ 36.026410] [<ffffffff816727e0>] tcp_rcv_state_process+0x190/0xda0
[ 36.027556] [<ffffffff81661f97>] ? __inet_lookup_established+0x47/0x170
[ 36.028784] [<ffffffff8167c2ad>] tcp_v4_do_rcv+0x16d/0x3d0
[ 36.029832] [<ffffffff812e6806>] ? security_sock_rcv_skb+0x16/0x20
[ 36.030936] [<ffffffff8167cc8a>] tcp_v4_rcv+0x77a/0x7b0
[ 36.031875] [<ffffffff816af8c3>] ? iptable_filter_hook+0x33/0x70
[ 36.032953] [<ffffffff81657d22>] ip_local_deliver_finish+0x92/0x1f0
[ 36.034065] [<ffffffff81657f1a>] ip_local_deliver+0x9a/0xb0
[ 36.035069] [<ffffffff81657c90>] ? ip_rcv+0x3d0/0x3d0
[ 36.035963] [<ffffffff81657569>] ip_rcv_finish+0x119/0x330
[ 36.036950] [<ffffffff81657ba7>] ip_rcv+0x2e7/0x3d0
[ 36.037847] [<ffffffff81610652>] __netif_receive_skb_core+0x552/0x930
[ 36.038994] [<ffffffff81610a57>] __netif_receive_skb+0x27/0x70
[ 36.040033] [<ffffffff81610b72>] process_backlog+0xd2/0x1f0
[ 36.041025] [<ffffffff81611482>] net_rx_action+0x122/0x310
[ 36.042007] [<ffffffff81076743>] __do_softirq+0x103/0x2f0
[ 36.042978] [<ffffffff81723e3c>] 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.dumazet@gmail.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Fixes: 222e83d2e0ae ("tcp: switch tcp_fastopen key generation to net_get_random_once")
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>