BMC/Intel-BMC/linux.git/net/ipv4/tcp.c, branch dev

tcp: fix recv with flags MSG_WAITALL | MSG_PEEK

2015-07-27T08:06:53+00:00

Currently, tcp_recvmsg enters a busy loop in sk_wait_data if called with flags = MSG_WAITALL | MSG_PEEK. sk_wait_data waits for sk_receive_queue not empty, but in this case, the receive queue is not empty, but does not contain any skb that we can use. Add a "last skb seen on receive queue" argument to sk_wait_data, so that it sleeps until the receive queue has new skbs. Link: https://bugzilla.kernel.org/show_bug.cgi?id=99461 Link: https://sourceware.org/bugzilla/show_bug.cgi?id=18493 Link: https://bugzilla.redhat.com/show_bug.cgi?id=1205258 Reported-by: Enrico Scholz Reported-by: Dan Searle Signed-off-by: Sabrina Dubroca Acked-by: Eric Dumazet Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2015-06-24T09:58:51+00:00

Conflicts: drivers/net/ethernet/mellanox/mlx4/main.c net/packet/af_packet.c Both conflicts were cases of simple overlapping changes. Signed-off-by: David S. Miller

tcp: Do not call tcp_fastopen_reset_cipher from interrupt context

2015-06-23T09:38:10+00:00

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

sock_diag: implement a get_info handler for inet

2015-06-16T02:49:22+00:00

This get_info handler will simply dispatch to the appropriate existing inet protocol handler. This patch also includes a new netlink attribute (INET_DIAG_PROTOCOL). This attribute is currently only used for multicast messages. Without this attribute, there is no way of knowing the IP protocol used by the socket information being broadcast. This attribute is not necessary in the 'dump' variant of this protocol (though it could easily be added) because dump requests are issued for specific family/protocol pairs. Tested: ss -E (note, the -E option has not yet been merged into the upstream version of ss). Signed-off-by: Craig Gallek Acked-by: Eric Dumazet Signed-off-by: David S. Miller

net: make skb_splice_bits more configureable

2015-05-25T04:06:59+00:00

Prepare skb_splice_bits to be able to deal with AF_UNIX sockets. AF_UNIX sockets don't use lock_sock/release_sock and thus we have to use a callback to make the locking and unlocking configureable. Signed-off-by: Hannes Frederic Sowa Acked-by: Eric Dumazet Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2015-05-23T05:22:35+00:00

Conflicts: drivers/net/ethernet/cadence/macb.c drivers/net/phy/phy.c include/linux/skbuff.h net/ipv4/tcp.c net/switchdev/switchdev.c Switchdev was a case of RTNH_H_{EXTERNAL --> OFFLOAD} renaming overlapping with net-next changes of various sorts. phy.c was a case of two changes, one adding a local variable to a function whilst the second was removing one. tcp.c overlapped a deadlock fix with the addition of new tcp_info statistic values. macb.c involved the addition of two zyncq device entries. skbuff.h involved adding back ipv4_daddr to nf_bridge_info whilst net-next changes put two other existing members of that struct into a union. Signed-off-by: David S. Miller

tcp: fix a potential deadlock in tcp_get_info()

2015-05-22T17:46:06+00:00

Taking socket spinlock in tcp_get_info() can deadlock, as inet_diag_dump_icsk() holds the &hashinfo->ehash_locks[i], while packet processing can use the reverse locking order. We could avoid this locking for TCP_LISTEN states, but lockdep would certainly get confused as all TCP sockets share same lockdep classes. [ 523.722504] ====================================================== [ 523.728706] [ INFO: possible circular locking dependency detected ] [ 523.734990] 4.1.0-dbg-DEV #1676 Not tainted [ 523.739202] ------------------------------------------------------- [ 523.745474] ss/18032 is trying to acquire lock: [ 523.750002] (slock-AF_INET){+.-...}, at: [] tcp_get_info+0x2c4/0x360 [ 523.758129] [ 523.758129] but task is already holding lock: [ 523.763968] (&(&hashinfo->ehash_locks[i])->rlock){+.-...}, at: [] inet_diag_dump_icsk+0x1d5/0x6c0 [ 523.774661] [ 523.774661] which lock already depends on the new lock. [ 523.774661] [ 523.782850] [ 523.782850] the existing dependency chain (in reverse order) is: [ 523.790326] -> #1 (&(&hashinfo->ehash_locks[i])->rlock){+.-...}: [ 523.796599] [] lock_acquire+0xbb/0x270 [ 523.802565] [] _raw_spin_lock+0x38/0x50 [ 523.808628] [] __inet_hash_nolisten+0x78/0x110 [ 523.815273] [] tcp_v4_syn_recv_sock+0x24b/0x350 [ 523.822067] [] tcp_check_req+0x3c1/0x500 [ 523.828199] [] tcp_v4_do_rcv+0x239/0x3d0 [ 523.834331] [] tcp_v4_rcv+0xa8e/0xc10 [ 523.840202] [] ip_local_deliver_finish+0x133/0x3e0 [ 523.847214] [] ip_local_deliver+0xaa/0xc0 [ 523.853440] [] ip_rcv_finish+0x168/0x5c0 [ 523.859624] [] ip_rcv+0x307/0x420 Lets use u64_sync infrastructure instead. As a bonus, 64bit arches get optimized, as these are nop for them. Fixes: 0df48c26d841 ("tcp: add tcpi_bytes_acked to tcp_info") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: add tcpi_segs_in and tcpi_segs_out to tcp_info

2015-05-22T03:25:21+00:00

This patch tracks the total number of inbound and outbound segments on a TCP socket. One may use this number to have an idea on connection quality when compared against the retransmissions. RFC4898 named these : tcpEStatsPerfSegsIn and tcpEStatsPerfSegsOut These are a 32bit field each and can be fetched both from TCP_INFO getsockopt() if one has a handle on a TCP socket, or from inet_diag netlink facility (iproute2/ss patch will follow) Note that tp->segs_out was placed near tp->snd_nxt for good data locality and minimal performance impact, while tp->segs_in was placed near tp->bytes_received for the same reason. Join work with Eric Dumazet. Note that received SYN are accounted on the listener, but sent SYNACK are not accounted. Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: ensure epoll edge trigger wakeup when write queue is empty

2015-05-21T22:52:47+00:00

We currently rely on the setting of SOCK_NOSPACE in the write() path to ensure that we wake up any epoll edge trigger waiters when acks return to free space in the write queue. However, if we fail to allocate even a single skb in the write queue, we could end up waiting indefinitely. Fix this by explicitly issuing a wakeup when we detect the condition of an empty write queue and a return value of -EAGAIN. This allows userspace to re-try as we expect this to be a temporary failure. I've tested this approach by artificially making sk_stream_alloc_skb() return NULL periodically. In that case, epoll edge trigger waiters will hang indefinitely in epoll_wait() without this patch. Signed-off-by: Jason Baron Acked-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: add a force_schedule argument to sk_stream_alloc_skb()

2015-05-21T20:56:40+00:00

In commit 8e4d980ac215 ("tcp: fix behavior for epoll edge trigger") we fixed a possible hang of TCP sockets under memory pressure, by allowing sk_stream_alloc_skb() to use sk_forced_mem_schedule() if no packet is in socket write queue. It turns out there are other cases where we want to force memory schedule : tcp_fragment() & tso_fragment() need to split a big TSO packet into two smaller ones. If we block here because of TCP memory pressure, we can effectively block TCP socket from sending new data. If no further ACK is coming, this hang would be definitive, and socket has no chance to effectively reduce its memory usage. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller