There is a race condition for an established connection that is being closed
by the guest: the refcnt is 4 at the end of hvs_release() (Note: here the
'remove_sock' is false):
1 for the initial value;
1 for the sk being in the bound list;
1 for the sk being in the connected list;
1 for the delayed close_work.
After hvs_release() finishes, __vsock_release() -> sock_put(sk) *may*
decrease the refcnt to 3.
Concurrently, hvs_close_connection() runs in another thread:
calls vsock_remove_sock() to decrease the refcnt by 2;
call sock_put() to decrease the refcnt to 0, and free the sk;
next, the "release_sock(sk)" may hang due to use-after-free.
In the above, after hvs_release() finishes, if hvs_close_connection() runs
faster than "__vsock_release() -> sock_put(sk)", then there is not any issue,
because at the beginning of hvs_close_connection(), the refcnt is still 4.
The issue can be resolved if an extra reference is taken when the
connection is established.
Fixes: a9eeb998c2 ("hv_sock: Add support for delayed close")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, hvsock can enter into a state where epoll_wait on EPOLLOUT will
not return even when the hvsock socket is writable, under some race
condition. This can happen under the following sequence:
- fd = socket(hvsocket)
- fd_out = dup(fd)
- fd_in = dup(fd)
- start a writer thread that writes data to fd_out with a combination of
epoll_wait(fd_out, EPOLLOUT) and
- start a reader thread that reads data from fd_in with a combination of
epoll_wait(fd_in, EPOLLIN)
- On the host, there are two threads that are reading/writing data to the
hvsocket
stack:
hvs_stream_has_space
hvs_notify_poll_out
vsock_poll
sock_poll
ep_poll
Race condition:
check for epollout from ep_poll():
assume no writable space in the socket
hvs_stream_has_space() returns 0
check for epollin from ep_poll():
assume socket has some free space < HVS_PKT_LEN(HVS_SEND_BUF_SIZE)
hvs_stream_has_space() will clear the channel pending send size
host will not notify the guest because the pending send size has
been cleared and so the hvsocket will never mark the
socket writable
Now, the EPOLLOUT will never return even if the socket write buffer is
empty.
The fix is to set the pending size to the default size and never change it.
This way the host will always notify the guest whenever the writable space
is bigger than the pending size. The host is already optimized to *only*
notify the guest when the pending size threshold boundary is crossed and
not everytime.
This change also reduces the cpu usage somewhat since hv_stream_has_space()
is in the hotpath of send:
vsock_stream_sendmsg()->hv_stream_has_space()
Earlier hv_stream_has_space was setting/clearing the pending size on every
call.
Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull networking fixes from David Miller:
"Lots of bug fixes here:
1) Out of bounds access in __bpf_skc_lookup, from Lorenz Bauer.
2) Fix rate reporting in cfg80211_calculate_bitrate_he(), from John
Crispin.
3) Use after free in psock backlog workqueue, from John Fastabend.
4) Fix source port matching in fdb peer flow rule of mlx5, from Raed
Salem.
5) Use atomic_inc_not_zero() in fl6_sock_lookup(), from Eric Dumazet.
6) Network header needs to be set for packet redirect in nfp, from
John Hurley.
7) Fix udp zerocopy refcnt, from Willem de Bruijn.
8) Don't assume linear buffers in vxlan and geneve error handlers,
from Stefano Brivio.
9) Fix TOS matching in mlxsw, from Jiri Pirko.
10) More SCTP cookie memory leak fixes, from Neil Horman.
11) Fix VLAN filtering in rtl8366, from Linus Walluij.
12) Various TCP SACK payload size and fragmentation memory limit fixes
from Eric Dumazet.
13) Use after free in pneigh_get_next(), also from Eric Dumazet.
14) LAPB control block leak fix from Jeremy Sowden"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (145 commits)
lapb: fixed leak of control-blocks.
tipc: purge deferredq list for each grp member in tipc_group_delete
ax25: fix inconsistent lock state in ax25_destroy_timer
neigh: fix use-after-free read in pneigh_get_next
tcp: fix compile error if !CONFIG_SYSCTL
hv_sock: Suppress bogus "may be used uninitialized" warnings
be2net: Fix number of Rx queues used for flow hashing
net: handle 802.1P vlan 0 packets properly
tcp: enforce tcp_min_snd_mss in tcp_mtu_probing()
tcp: add tcp_min_snd_mss sysctl
tcp: tcp_fragment() should apply sane memory limits
tcp: limit payload size of sacked skbs
Revert "net: phylink: set the autoneg state in phylink_phy_change"
bpf: fix nested bpf tracepoints with per-cpu data
bpf: Fix out of bounds memory access in bpf_sk_storage
vsock/virtio: set SOCK_DONE on peer shutdown
net: dsa: rtl8366: Fix up VLAN filtering
net: phylink: set the autoneg state in phylink_phy_change
net: add high_order_alloc_disable sysctl/static key
tcp: add tcp_tx_skb_cache sysctl
...
gcc 8.2.0 may report these bogus warnings under some condition:
warning: ‘vnew’ may be used uninitialized in this function
warning: ‘hvs_new’ may be used uninitialized in this function
Actually, the 2 pointers are only initialized and used if the variable
"conn_from_host" is true. The code is not buggy here.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms and conditions of the gnu general public license
version 2 as published by the free software foundation this program
is distributed in the hope it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 263 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141901.208660670@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, the hv_sock send() iterates once over the buffer, puts data into
the VMBUS channel and returns. It doesn't maximize on the case when there
is a simultaneous reader draining data from the channel. In such a case,
the send() can maximize the bandwidth (and consequently minimize the cpu
cycles) by iterating until the channel is found to be full.
Perf data:
Total Data Transfer: 10GB/iteration
Single threaded reader/writer, Linux hvsocket writer with Windows hvsocket
reader
Packet size: 64KB
CPU sys time was captured using the 'time' command for the writer to send
10GB of data.
'Send Buffer Loop' is with the patch applied.
The values below are over 10 iterations.
|--------------------------------------------------------|
| | Current | Send Buffer Loop |
|--------------------------------------------------------|
| | Throughput | CPU sys | Throughput | CPU sys |
| | (MB/s) | time (s) | (MB/s) | time (s) |
|--------------------------------------------------------|
| Min | 407 | 7.048 | 401 | 5.958 |
|--------------------------------------------------------|
| Max | 455 | 7.563 | 542 | 6.993 |
|--------------------------------------------------------|
| Avg | 440 | 7.411 | 451 | 6.639 |
|--------------------------------------------------------|
| Median | 446 | 7.417 | 447 | 6.761 |
|--------------------------------------------------------|
Observation:
1. The avg throughput doesn't really change much with this change for this
scenario. This is most probably because the bottleneck on throughput is
somewhere else.
2. The average system (or kernel) cpu time goes down by 10%+ with this
change, for the same amount of data transfer.
Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, the hv_sock buffer size is static and can't scale to the
bandwidth requirements of the application. This change allows the
applications to influence the socket buffer sizes using the SO_SNDBUF and
the SO_RCVBUF socket options.
Few interesting points to note:
1. Since the VMBUS does not allow a resize operation of the ring size, the
socket buffer size option should be set prior to establishing the
connection for it to take effect.
2. Setting the socket option comes with the cost of that much memory being
reserved/allocated by the kernel, for the lifetime of the connection.
Perf data:
Total Data Transfer: 1GB
Single threaded reader/writer
Results below are summarized over 10 iterations.
Linux hvsocket writer + Windows hvsocket reader:
|---------------------------------------------------------------------------------------------|
|Packet size -> | 128B | 1KB | 4KB | 64KB |
|---------------------------------------------------------------------------------------------|
|SO_SNDBUF size | | Throughput in MB/s (min/max/avg/median): |
| v | |
|---------------------------------------------------------------------------------------------|
| Default | 109/118/114/116 | 636/774/701/700 | 435/507/480/476 | 410/491/462/470 |
| 16KB | 110/116/112/111 | 575/705/662/671 | 749/900/854/869 | 592/824/692/676 |
| 32KB | 108/120/115/115 | 703/823/767/772 | 718/878/850/866 | 1593/2124/2000/2085 |
| 64KB | 108/119/114/114 | 592/732/683/688 | 805/934/903/911 | 1784/1943/1862/1843 |
|---------------------------------------------------------------------------------------------|
Windows hvsocket writer + Linux hvsocket reader:
|---------------------------------------------------------------------------------------------|
|Packet size -> | 128B | 1KB | 4KB | 64KB |
|---------------------------------------------------------------------------------------------|
|SO_RCVBUF size | | Throughput in MB/s (min/max/avg/median): |
| v | |
|---------------------------------------------------------------------------------------------|
| Default | 69/82/75/73 | 313/343/333/336 | 418/477/446/445 | 659/701/676/678 |
| 16KB | 69/83/76/77 | 350/401/375/382 | 506/548/517/516 | 602/624/615/615 |
| 32KB | 62/83/73/73 | 471/529/496/494 | 830/1046/935/939 | 944/1180/1070/1100 |
| 64KB | 64/70/68/69 | 467/533/501/497 | 1260/1590/1430/1431 | 1605/1819/1670/1660 |
|---------------------------------------------------------------------------------------------|
Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, hvsock does not implement any delayed or background close
logic. Whenever the hvsock socket is closed, a FIN is sent to the peer, and
the last reference to the socket is dropped, which leads to a call to
.destruct where the socket can hang indefinitely waiting for the peer to
close it's side. The can cause the user application to hang in the close()
call.
This change implements proper STREAM(TCP) closing handshake mechanism by
sending the FIN to the peer and the waiting for the peer's FIN to arrive
for a given timeout. On timeout, it will try to terminate the connection
(i.e. a RST). This is in-line with other socket providers such as virtio.
This change does not address the hang in the vmbus_hvsock_device_unregister
where it waits indefinitely for the host to rescind the channel. That
should be taken up as a separate fix.
Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since commit 3b4477d2dc ("VSOCK: use TCP
state constants for sk_state") VSOCK has used TCP_* constants for
sk_state.
Commit b4562ca792 ("hv_sock: add locking
in the open/close/release code paths") reintroduced the SS_DISCONNECTING
constant.
This patch replaces the old SS_DISCONNECTING with the new TCP_CLOSING
constant.
CC: Dexuan Cui <decui@microsoft.com>
CC: Cathy Avery <cavery@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There were quite a few overlapping sets of changes here.
Daniel's bug fix for off-by-ones in the new BPF branch instructions,
along with the added allowances for "data_end > ptr + x" forms
collided with the metadata additions.
Along with those three changes came veritifer test cases, which in
their final form I tried to group together properly. If I had just
trimmed GIT's conflict tags as-is, this would have split up the
meta tests unnecessarily.
In the socketmap code, a set of preemption disabling changes
overlapped with the rename of bpf_compute_data_end() to
bpf_compute_data_pointers().
Changes were made to the mv88e6060.c driver set addr method
which got removed in net-next.
The hyperv transport socket layer had a locking change in 'net'
which overlapped with a change of socket state macro usage
in 'net-next'.
Signed-off-by: David S. Miller <davem@davemloft.net>
Without the patch, when hvs_open_connection() hasn't completely established
a connection (e.g. it has changed sk->sk_state to SS_CONNECTED, but hasn't
inserted the sock into the connected queue), vsock_stream_connect() may see
the sk_state change and return the connection to the userspace, and next
when the userspace closes the connection quickly, hvs_release() may not see
the connection in the connected queue; finally hvs_open_connection()
inserts the connection into the queue, but we won't be able to purge the
connection for ever.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Cathy Avery <cavery@redhat.com>
Cc: Rolf Neugebauer <rolf.neugebauer@docker.com>
Cc: Marcelo Cerri <marcelo.cerri@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There are two state fields: socket->state and sock->sk_state. The
socket->state field uses SS_UNCONNECTED, SS_CONNECTED, etc while the
sock->sk_state typically uses values that match TCP state constants
(TCP_CLOSE, TCP_ESTABLISHED). AF_VSOCK does not follow this convention
and instead uses SS_* constants for both fields.
The sk_state field will be exposed to userspace through the vsock_diag
interface for ss(8), netstat(8), and other programs.
This patch switches sk_state to TCP state constants so that the meaning
of this field is consistent with other address families. Not just
AF_INET and AF_INET6 use the TCP constants, AF_UNIX and others do too.
The following mapping was used to convert the code:
SS_FREE -> TCP_CLOSE
SS_UNCONNECTED -> TCP_CLOSE
SS_CONNECTING -> TCP_SYN_SENT
SS_CONNECTED -> TCP_ESTABLISHED
SS_DISCONNECTING -> TCP_CLOSING
VSOCK_SS_LISTEN -> TCP_LISTEN
In __vsock_create() the sk_state initialization was dropped because
sock_init_data() already initializes sk_state to TCP_CLOSE.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Hyper-V Sockets (hv_sock) supplies a byte-stream based communication
mechanism between the host and the guest. It uses VMBus ringbuffer as the
transportation layer.
With hv_sock, applications between the host (Windows 10, Windows Server
2016 or newer) and the guest can talk with each other using the traditional
socket APIs.
More info about Hyper-V Sockets is available here:
"Make your own integration services":
https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/user-guide/make-integration-service
The patch implements the necessary support in Linux guest by introducing a new
vsock transport for AF_VSOCK.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Andy King <acking@vmware.com>
Cc: Dmitry Torokhov <dtor@vmware.com>
Cc: George Zhang <georgezhang@vmware.com>
Cc: Jorgen Hansen <jhansen@vmware.com>
Cc: Reilly Grant <grantr@vmware.com>
Cc: Asias He <asias@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Cathy Avery <cavery@redhat.com>
Cc: Rolf Neugebauer <rolf.neugebauer@docker.com>
Cc: Marcelo Cerri <marcelo.cerri@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Dexuan Cui