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Small conflict around locking in rxrpc_process_event() -
channel_lock moved to bundle in next, while state lock
needs _bh() from net.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When a new incoming call arrives at an userspace rxrpc socket on a new
connection that has a security class set, the code currently pushes it onto
the accept queue to hold a ref on it for the socket. This doesn't work,
however, as recvmsg() pops it off, notices that it's in the SERVER_SECURING
state and discards the ref. This means that the call runs out of refs too
early and the kernel oopses.
By contrast, a kernel rxrpc socket manually pre-charges the incoming call
pool with calls that already have user call IDs assigned, so they are ref'd
by the call tree on the socket.
Change the mode of operation for userspace rxrpc server sockets to work
like this too. Although this is a UAPI change, server sockets aren't
currently functional.
Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>
The alloc_error field in the rxrpc_bundle struct should be signed as it has
negative error codes assigned to it. Checks directly on it may then fail,
and may produce a warning like this:
net/rxrpc/conn_client.c:662 rxrpc_wait_for_channel()
warn: 'bundle->alloc_error' is unsigned
Fixes: 245500d853 ("rxrpc: Rewrite the client connection manager")
Reported-by Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Rewrite the rxrpc client connection manager so that it can support multiple
connections for a given security key to a peer. The following changes are
made:
(1) For each open socket, the code currently maintains an rbtree with the
connections placed into it, keyed by communications parameters. This
is tricky to maintain as connections can be culled from the tree or
replaced within it. Connections can require replacement for a number
of reasons, e.g. their IDs span too great a range for the IDR data
type to represent efficiently, the call ID numbers on that conn would
overflow or the conn got aborted.
This is changed so that there's now a connection bundle object placed
in the tree, keyed on the same parameters. The bundle, however, does
not need to be replaced.
(2) An rxrpc_bundle object can now manage the available channels for a set
of parallel connections. The lock that manages this is moved there
from the rxrpc_connection struct (channel_lock).
(3) There'a a dummy bundle for all incoming connections to share so that
they have a channel_lock too. It might be better to give each
incoming connection its own bundle. This bundle is not needed to
manage which channels incoming calls are made on because that's the
solely at whim of the client.
(4) The restrictions on how many client connections are around are
removed. Instead, a previous patch limits the number of client calls
that can be allocated. Ordinarily, client connections are reaped
after 2 minutes on the idle queue, but when more than a certain number
of connections are in existence, the reaper starts reaping them after
2s of idleness instead to get the numbers back down.
It could also be made such that new call allocations are forced to
wait until the number of outstanding connections subsides.
Signed-off-by: David Howells <dhowells@redhat.com>
Impose a maximum on the number of client rxrpc calls that are allowed
simultaneously. This will be in lieu of a maximum number of client
connections as this is easier to administed as, unlike connections, calls
aren't reusable (to be changed in a subsequent patch)..
This doesn't affect the limits on service calls and connections.
Signed-off-by: David Howells <dhowells@redhat.com>
The Rx protocol has a mechanism to help generate RTT samples that works by
a client transmitting a REQUESTED-type ACK when it receives a DATA packet
that has the REQUEST_ACK flag set.
The peer, however, may interpose other ACKs before transmitting the
REQUESTED-ACK, as can be seen in the following trace excerpt:
rxrpc_tx_data: c=00000044 DATA d0b5ece8:00000001 00000001 q=00000001 fl=07
rxrpc_rx_ack: c=00000044 00000001 PNG r=00000000 f=00000002 p=00000000 n=0
rxrpc_rx_ack: c=00000044 00000002 REQ r=00000001 f=00000002 p=00000001 n=0
...
DATA packet 1 (q=xx) has REQUEST_ACK set (bit 1 of fl=xx). The incoming
ping (labelled PNG) hard-acks the request DATA packet (f=xx exceeds the
sequence number of the DATA packet), causing it to be discarded from the Tx
ring. The ACK that was requested (labelled REQ, r=xx references the serial
of the DATA packet) comes after the ping, but the sk_buff holding the
timestamp has gone and the RTT sample is lost.
This is particularly noticeable on RPC calls used to probe the service
offered by the peer. A lot of peers end up with an unknown RTT because we
only ever sent a single RPC. This confuses the server rotation algorithm.
Fix this by caching the information about the outgoing packet in RTT
calculations in the rxrpc_call struct rather than looking in the Tx ring.
A four-deep buffer is maintained and both REQUEST_ACK-flagged DATA and
PING-ACK transmissions are recorded in there. When the appropriate
response ACK is received, the buffer is checked for a match and, if found,
an RTT sample is recorded.
If a received ACK refers to a packet with a later serial number than an
entry in the cache, that entry is presumed lost and the entry is made
available to record a new transmission.
ACKs types other than REQUESTED-type and PING-type cause any matching
sample to be cancelled as they don't necessarily represent a useful
measurement.
If there's no space in the buffer on ping/data transmission, the sample
base is discarded.
Fixes: 50235c4b5a ("rxrpc: Obtain RTT data by requesting ACKs on DATA packets")
Signed-off-by: David Howells <dhowells@redhat.com>
Rework the remaining setsockopt code to pass a sockptr_t instead of a
plain user pointer. This removes the last remaining set_fs(KERNEL_DS)
outside of architecture specific code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org> [ieee802154]
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move the handling of call completion out of line so that the next patch can
add more code in that area.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
rxrpc currently uses a fixed 4s retransmission timeout until the RTT is
sufficiently sampled. This can cause problems with some fileservers with
calls to the cache manager in the afs filesystem being dropped from the
fileserver because a packet goes missing and the retransmission timeout is
greater than the call expiry timeout.
Fix this by:
(1) Copying the RTT/RTO calculation code from Linux's TCP implementation
and altering it to fit rxrpc.
(2) Altering the various users of the RTT to make use of the new SRTT
value.
(3) Replacing the use of rxrpc_resend_timeout to use the calculated RTO
value instead (which is needed in jiffies), along with a backoff.
Notes:
(1) rxrpc provides RTT samples by matching the serial numbers on outgoing
DATA packets that have the RXRPC_REQUEST_ACK set and PING ACK packets
against the reference serial number in incoming REQUESTED ACK and
PING-RESPONSE ACK packets.
(2) Each packet that is transmitted on an rxrpc connection gets a new
per-connection serial number, even for retransmissions, so an ACK can
be cross-referenced to a specific trigger packet. This allows RTT
information to be drawn from retransmitted DATA packets also.
(3) rxrpc maintains the RTT/RTO state on the rxrpc_peer record rather than
on an rxrpc_call because many RPC calls won't live long enough to
generate more than one sample.
(4) The calculated SRTT value is in units of 8ths of a microsecond rather
than nanoseconds.
The (S)RTT and RTO values are displayed in /proc/net/rxrpc/peers.
Fixes: 17926a7932 ([AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both"")
Signed-off-by: David Howells <dhowells@redhat.com>
Fix the handling of signals in client rxrpc calls made by the afs
filesystem. Ignore signals completely, leaving call abandonment or
connection loss to be detected by timeouts inside AF_RXRPC.
Allowing a filesystem call to be interrupted after the entire request has
been transmitted and an abort sent means that the server may or may not
have done the action - and we don't know. It may even be worse than that
for older servers.
Fixes: bc5e3a546d ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Signed-off-by: David Howells <dhowells@redhat.com>
Fix the interruptibility of kernel-initiated client calls so that they're
either only interruptible when they're waiting for a call slot to come
available or they're not interruptible at all. Either way, they're not
interruptible during transmission.
This should help prevent StoreData calls from being interrupted when
writeback is in progress. It doesn't, however, handle interruption during
the receive phase.
Userspace-initiated calls are still interruptable. After the signal has
been handled, sendmsg() will return the amount of data copied out of the
buffer and userspace can perform another sendmsg() call to continue
transmission.
Fixes: bc5e3a546d ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Signed-off-by: David Howells <dhowells@redhat.com>
When a call is disconnected, the connection pointer from the call is
cleared to make sure it isn't used again and to prevent further attempted
transmission for the call. Unfortunately, there might be a daemon trying
to use it at the same time to transmit a packet.
Fix this by keeping call->conn set, but setting a flag on the call to
indicate disconnection instead.
Remove also the bits in the transmission functions where the conn pointer is
checked and a ref taken under spinlock as this is now redundant.
Fixes: 8d94aa381d ("rxrpc: Calls shouldn't hold socket refs")
Signed-off-by: David Howells <dhowells@redhat.com>
The introduction of a split between the reference count on rxrpc_local
objects and the usage count didn't quite go far enough. A number of kernel
work items need to make use of the socket to perform transmission. These
also need to get an active count on the local object to prevent the socket
from being closed.
Fix this by getting the active count in those places.
Also split out the raw active count get/put functions as these places tend
to hold refs on the rxrpc_local object already, so getting and putting an
extra object ref is just a waste of time.
The problem can lead to symptoms like:
BUG: kernel NULL pointer dereference, address: 0000000000000018
..
CPU: 2 PID: 818 Comm: kworker/u9:0 Not tainted 5.5.0-fscache+ #51
...
RIP: 0010:selinux_socket_sendmsg+0x5/0x13
...
Call Trace:
security_socket_sendmsg+0x2c/0x3e
sock_sendmsg+0x1a/0x46
rxrpc_send_keepalive+0x131/0x1ae
rxrpc_peer_keepalive_worker+0x219/0x34b
process_one_work+0x18e/0x271
worker_thread+0x1a3/0x247
kthread+0xe6/0xeb
ret_from_fork+0x1f/0x30
Fixes: 730c5fd42c ("rxrpc: Fix local endpoint refcounting")
Signed-off-by: David Howells <dhowells@redhat.com>
Fix rxrpc_new_incoming_call() to check that we have a suitable service key
available for the combination of service ID and security class of a new
incoming call - and to reject calls for which we don't.
This causes an assertion like the following to appear:
rxrpc: Assertion failed - 6(0x6) == 12(0xc) is false
kernel BUG at net/rxrpc/call_object.c:456!
Where call->state is RXRPC_CALL_SERVER_SECURING (6) rather than
RXRPC_CALL_COMPLETE (12).
Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
When rxrpc_recvmsg_data() sets the return value to 1 because it's drained
all the data for the last packet, it checks the last-packet flag on the
whole packet - but this is wrong, since the last-packet flag is only set on
the final subpacket of the last jumbo packet. This means that a call that
receives its last packet in a jumbo packet won't complete properly.
Fix this by having rxrpc_locate_data() determine the last-packet state of
the subpacket it's looking at and passing that back to the caller rather
than having the caller look in the packet header. The caller then needs to
cache this in the rxrpc_call struct as rxrpc_locate_data() isn't then
called again for this packet.
Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Fixes: e2de6c4048 ("rxrpc: Use info in skbuff instead of reparsing a jumbo packet")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix the cleanup of the crypto state on a call after the call has been
disconnected. As the call has been disconnected, its connection ref has
been discarded and so we can't go through that to get to the security ops
table.
Fix this by caching the security ops pointer in the rxrpc_call struct and
using that when freeing the call security state. Also use this in other
places we're dealing with call-specific security.
The symptoms look like:
BUG: KASAN: use-after-free in rxrpc_release_call+0xb2d/0xb60
net/rxrpc/call_object.c:481
Read of size 8 at addr ffff888062ffeb50 by task syz-executor.5/4764
Fixes: 1db88c5343 ("rxrpc: Fix -Wframe-larger-than= warnings from on-stack crypto")
Reported-by: syzbot+eed305768ece6682bb7f@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
When a local endpoint is ceases to be in use, such as when the kafs module
is unloaded, the kernel will emit an assertion failure if there are any
outstanding client connections:
rxrpc: Assertion failed
------------[ cut here ]------------
kernel BUG at net/rxrpc/local_object.c:433!
and even beyond that, will evince other oopses if there are service
connections still present.
Fix this by:
(1) Removing the triggering of connection reaping when an rxrpc socket is
released. These don't actually clean up the connections anyway - and
further, the local endpoint may still be in use through another
socket.
(2) Mark the local endpoint as dead when we start the process of tearing
it down.
(3) When destroying a local endpoint, strip all of its client connections
from the idle list and discard the ref on each that the list was
holding.
(4) When destroying a local endpoint, call the service connection reaper
directly (rather than through a workqueue) to immediately kill off all
outstanding service connections.
(5) Make the service connection reaper reap connections for which the
local endpoint is marked dead.
Only after destroying the connections can we close the socket lest we get
an oops in a workqueue that's looking at a connection or a peer.
Fixes: 3d18cbb7fd ("rxrpc: Fix conn expiry timers")
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The in-place decryption routines in AF_RXRPC's rxkad security module
currently call skb_cow_data() to make sure the data isn't shared and that
the skb can be written over. This has a problem, however, as the softirq
handler may be still holding a ref or the Rx ring may be holding multiple
refs when skb_cow_data() is called in rxkad_verify_packet() - and so
skb_shared() returns true and __pskb_pull_tail() dislikes that. If this
occurs, something like the following report will be generated.
kernel BUG at net/core/skbuff.c:1463!
...
RIP: 0010:pskb_expand_head+0x253/0x2b0
...
Call Trace:
__pskb_pull_tail+0x49/0x460
skb_cow_data+0x6f/0x300
rxkad_verify_packet+0x18b/0xb10 [rxrpc]
rxrpc_recvmsg_data.isra.11+0x4a8/0xa10 [rxrpc]
rxrpc_kernel_recv_data+0x126/0x240 [rxrpc]
afs_extract_data+0x51/0x2d0 [kafs]
afs_deliver_fs_fetch_data+0x188/0x400 [kafs]
afs_deliver_to_call+0xac/0x430 [kafs]
afs_wait_for_call_to_complete+0x22f/0x3d0 [kafs]
afs_make_call+0x282/0x3f0 [kafs]
afs_fs_fetch_data+0x164/0x300 [kafs]
afs_fetch_data+0x54/0x130 [kafs]
afs_readpages+0x20d/0x340 [kafs]
read_pages+0x66/0x180
__do_page_cache_readahead+0x188/0x1a0
ondemand_readahead+0x17d/0x2e0
generic_file_read_iter+0x740/0xc10
__vfs_read+0x145/0x1a0
vfs_read+0x8c/0x140
ksys_read+0x4a/0xb0
do_syscall_64+0x43/0xf0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fix this by using skb_unshare() instead in the input path for DATA packets
that have a security index != 0. Non-DATA packets don't need in-place
encryption and neither do unencrypted DATA packets.
Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Reported-by: Julian Wollrath <jwollrath@web.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Use the previously-added transmit-phase skbuff private flag to simplify the
socket buffer tracing a bit. Which phase the skbuff comes from can now be
divined from the skb rather than having to be guessed from the call state.
We can also reduce the number of rxrpc_skb_trace values by eliminating the
difference between Tx and Rx in the symbols.
Signed-off-by: David Howells <dhowells@redhat.com>
Add a flag in the private data on an skbuff to indicate that this is a
transmission-phase buffer rather than a receive-phase buffer.
Signed-off-by: David Howells <dhowells@redhat.com>
Use the information now cached in the skbuff private data to avoid the need
to reparse a jumbo packet. We can find all the subpackets by dead
reckoning, so it's only necessary to note how many there are, whether the
last one is flagged as LAST_PACKET and whether any have the REQUEST_ACK
flag set.
This is necessary as once recvmsg() can see the packet, it can start
modifying it, such as doing in-place decryption.
Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>
Improve the information stored about jumbo packets so that we don't need to
reparse them so much later.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>
Don't bother generating maxSkew in the ACK packet as it has been obsolete
since AFS 3.1.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>
The object lifetime management on the rxrpc_local struct is broken in that
the rxrpc_local_processor() function is expected to clean up and remove an
object - but it may get requeued by packets coming in on the backing UDP
socket once it starts running.
This may result in the assertion in rxrpc_local_rcu() firing because the
memory has been scheduled for RCU destruction whilst still queued:
rxrpc: Assertion failed
------------[ cut here ]------------
kernel BUG at net/rxrpc/local_object.c:468!
Note that if the processor comes around before the RCU free function, it
will just do nothing because ->dead is true.
Fix this by adding a separate refcount to count active users of the
endpoint that causes the endpoint to be destroyed when it reaches 0.
The original refcount can then be used to refcount objects through the work
processor and cause the memory to be rcu freed when that reaches 0.
Fixes: 4f95dd78a7 ("rxrpc: Rework local endpoint management")
Reported-by: syzbot+1e0edc4b8b7494c28450@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
rxkad sometimes triggers a warning about oversized stack frames when
building with clang for a 32-bit architecture:
net/rxrpc/rxkad.c:243:12: error: stack frame size of 1088 bytes in function 'rxkad_secure_packet' [-Werror,-Wframe-larger-than=]
net/rxrpc/rxkad.c:501:12: error: stack frame size of 1088 bytes in function 'rxkad_verify_packet' [-Werror,-Wframe-larger-than=]
The problem is the combination of SYNC_SKCIPHER_REQUEST_ON_STACK() in
rxkad_verify_packet()/rxkad_secure_packet() with the relatively large
scatterlist in rxkad_verify_packet_1()/rxkad_secure_packet_encrypt().
The warning does not show up when using gcc, which does not inline the
functions as aggressively, but the problem is still the same.
Allocate the cipher buffers from the slab instead, caching the allocated
packet crypto request memory used for DATA packet crypto in the rxrpc_call
struct.
Fixes: 17926a7932 ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is a potential deadlock in rxrpc_peer_keepalive_dispatch() whereby
rxrpc_put_peer() is called with the peer_hash_lock held, but if it reduces
the peer's refcount to 0, rxrpc_put_peer() calls __rxrpc_put_peer() - which
the tries to take the already held lock.
Fix this by providing a version of rxrpc_put_peer() that can be called in
situations where the lock is already held.
The bug may produce the following lockdep report:
============================================
WARNING: possible recursive locking detected
5.2.0-next-20190718 #41 Not tainted
--------------------------------------------
kworker/0:3/21678 is trying to acquire lock:
00000000aa5eecdf (&(&rxnet->peer_hash_lock)->rlock){+.-.}, at: spin_lock_bh
/./include/linux/spinlock.h:343 [inline]
00000000aa5eecdf (&(&rxnet->peer_hash_lock)->rlock){+.-.}, at:
__rxrpc_put_peer /net/rxrpc/peer_object.c:415 [inline]
00000000aa5eecdf (&(&rxnet->peer_hash_lock)->rlock){+.-.}, at:
rxrpc_put_peer+0x2d3/0x6a0 /net/rxrpc/peer_object.c:435
but task is already holding lock:
00000000aa5eecdf (&(&rxnet->peer_hash_lock)->rlock){+.-.}, at: spin_lock_bh
/./include/linux/spinlock.h:343 [inline]
00000000aa5eecdf (&(&rxnet->peer_hash_lock)->rlock){+.-.}, at:
rxrpc_peer_keepalive_dispatch /net/rxrpc/peer_event.c:378 [inline]
00000000aa5eecdf (&(&rxnet->peer_hash_lock)->rlock){+.-.}, at:
rxrpc_peer_keepalive_worker+0x6b3/0xd02 /net/rxrpc/peer_event.c:430
Fixes: 330bdcfadc ("rxrpc: Fix the keepalive generator [ver #2]")
Reported-by: syzbot+72af434e4b3417318f84@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Allow kernel services using AF_RXRPC to indicate that a call should be
non-interruptible. This allows kafs to make things like lock-extension and
writeback data storage calls non-interruptible.
If this is set, signals will be ignored for operations on that call where
possible - such as waiting to get a call channel on an rxrpc connection.
It doesn't prevent UDP sendmsg from being interrupted, but that will be
handled by packet retransmission.
rxrpc_kernel_recv_data() isn't affected by this since that never waits,
preferring instead to return -EAGAIN and leave the waiting to the caller.
Userspace initiated calls can't be set to be uninterruptible at this time.
Signed-off-by: David Howells <dhowells@redhat.com>
The rxrpc packet serial number cannot be safely used to compute out of
order ack packets for several reasons:
1. The allocation of serial numbers cannot be assumed to imply the order
by which acks are populated and transmitted. In some rxrpc
implementations, delayed acks and ping acks are transmitted
asynchronously to the receipt of data packets and so may be transmitted
out of order. As a result, they can race with idle acks.
2. Serial numbers are allocated by the rxrpc connection and not the call
and as such may wrap independently if multiple channels are in use.
In any case, what matters is whether the ack packet provides new
information relating to the bounds of the window (the firstPacket and
previousPacket in the ACK data).
Fix this by discarding packets that appear to wind back the window bounds
rather than on serial number procession.
Fixes: 298bc15b20 ("rxrpc: Only take the rwind and mtu values from latest ACK")
Signed-off-by: Jeffrey Altman <jaltman@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The changes introduced to allow rxrpc calls to be retried creates an issue
when it comes to refcounting afs_call structs. The problem is that when
rxrpc_send_data() queues the last packet for an asynchronous call, the
following sequence can occur:
(1) The notify_end_tx callback is invoked which causes the state in the
afs_call to be changed from AFS_CALL_CL_REQUESTING or
AFS_CALL_SV_REPLYING.
(2) afs_deliver_to_call() can then process event notifications from rxrpc
on the async_work queue.
(3) Delivery of events, such as an abort from the server, can cause the
afs_call state to be changed to AFS_CALL_COMPLETE on async_work.
(4) For an asynchronous call, afs_process_async_call() notes that the call
is complete and tried to clean up all the refs on async_work.
(5) rxrpc_send_data() might return the amount of data transferred
(success) or an error - which could in turn reflect a local error or a
received error.
Synchronising the clean up after rxrpc_kernel_send_data() returns an error
with the asynchronous cleanup is then tricky to get right.
Mostly revert commit c038a58ccf. The two API
functions the original commit added aren't currently used. This makes
rxrpc_kernel_send_data() always return successfully if it queued the data
it was given.
Note that this doesn't affect synchronous calls since their Rx notification
function merely pokes a wait queue and does not refcounting. The
asynchronous call notification function *has* to do refcounting and pass a
ref over the work item to avoid the need to sync the workqueue in call
cleanup.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If the network becomes (partially) unavailable, say by disabling IPv6, the
background ACK transmission routine can get itself into a tizzy by
proposing immediate ACK retransmission. Since we're in the call event
processor, that happens immediately without returning to the workqueue
manager.
The condition should clear after a while when either the network comes back
or the call times out.
Fix this by:
(1) When re-proposing an ACK on failed Tx, don't schedule it immediately.
This will allow a certain amount of time to elapse before we try
again.
(2) Enforce a return to the workqueue manager after a certain number of
iterations of the call processing loop.
(3) Add a backoff delay that increases the delay on deferred ACKs by a
jiffy per failed transmission to a limit of HZ. The backoff delay is
cleared on a successful return from kernel_sendmsg().
(4) Cancel calls immediately if the opening sendmsg fails. The layer
above can arrange retransmission or rotate to another server.
Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add /proc/net/rxrpc/peers to display the list of peers currently active.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts were easy to resolve using immediate context mostly,
except the cls_u32.c one where I simply too the entire HEAD
chunk.
Signed-off-by: David S. Miller <davem@davemloft.net>
The rxrpc_input_packet() function and its call tree was built around the
assumption that data_ready() handler called from UDP to inform a kernel
service that there is data to be had was non-reentrant. This means that
certain locking could be dispensed with.
This, however, turns out not to be the case with a multi-queue network card
that can deliver packets to multiple cpus simultaneously. Each of those
cpus can be in the rxrpc_input_packet() function at the same time.
Fix by adding or changing some structure members:
(1) Add peer->rtt_input_lock to serialise access to the RTT buffer.
(2) Make conn->service_id into a 32-bit variable so that it can be
cmpxchg'd on all arches.
(3) Add call->input_lock to serialise access to the Rx/Tx state. Note
that although the Rx and Tx states are (almost) entirely separate,
there's no point completing the separation and having separate locks
since it's a bi-phasal RPC protocol rather than a bi-direction
streaming protocol. Data transmission and data reception do not take
place simultaneously on any particular call.
and making the following functional changes:
(1) In rxrpc_input_data(), hold call->input_lock around the core to
prevent simultaneous producing of packets into the Rx ring and
updating of tracking state for a particular call.
(2) In rxrpc_input_ping_response(), only read call->ping_serial once, and
check it before checking RXRPC_CALL_PINGING as that's a cheaper test.
The bit test and bit clear can then be combined. No further locking
is needed here.
(3) In rxrpc_input_ack(), take call->input_lock after we've parsed much of
the ACK packet. The superseded ACK check is then done both before and
after the lock is taken.
The handing of ackinfo data is split, parsing before the lock is taken
and processing with it held. This is keyed on rxMTU being non-zero.
Congestion management is also done within the locked section.
(4) In rxrpc_input_ackall(), take call->input_lock around the Tx window
rotation. The ACKALL packet carries no information and is only really
useful after all packets have been transmitted since it's imprecise.
(5) In rxrpc_input_implicit_end_call(), we use rx->incoming_lock to
prevent calls being simultaneously implicitly ended on two cpus and
also to prevent any races with incoming call setup.
(6) In rxrpc_input_packet(), use cmpxchg() to effect the service upgrade
on a connection. It is only permitted to happen once for a
connection.
(7) In rxrpc_new_incoming_call(), we have to recheck the routing inside
rx->incoming_lock to see if someone else set up the call, connection
or peer whilst we were getting there. We can't trust the values from
the earlier routing check unless we pin refs on them - which we want
to avoid.
Further, we need to allow for an incoming call to have its state
changed on another CPU between us making it live and us adjusting it
because the conn is now in the RXRPC_CONN_SERVICE state.
(8) In rxrpc_peer_add_rtt(), take peer->rtt_input_lock around the access
to the RTT buffer. Don't need to lock around setting peer->rtt.
For reference, the inventory of state-accessing or state-altering functions
used by the packet input procedure is:
> rxrpc_input_packet()
* PACKET CHECKING
* ROUTING
> rxrpc_post_packet_to_local()
> rxrpc_find_connection_rcu() - uses RCU
> rxrpc_lookup_peer_rcu() - uses RCU
> rxrpc_find_service_conn_rcu() - uses RCU
> idr_find() - uses RCU
* CONNECTION-LEVEL PROCESSING
- Service upgrade
- Can only happen once per conn
! Changed to use cmpxchg
> rxrpc_post_packet_to_conn()
- Setting conn->hi_serial
- Probably safe not using locks
- Maybe use cmpxchg
* CALL-LEVEL PROCESSING
> Old-call checking
> rxrpc_input_implicit_end_call()
> rxrpc_call_completed()
> rxrpc_queue_call()
! Need to take rx->incoming_lock
> __rxrpc_disconnect_call()
> rxrpc_notify_socket()
> rxrpc_new_incoming_call()
- Uses rx->incoming_lock for the entire process
- Might be able to drop this earlier in favour of the call lock
> rxrpc_incoming_call()
! Conflicts with rxrpc_input_implicit_end_call()
> rxrpc_send_ping()
- Don't need locks to check rtt state
> rxrpc_propose_ACK
* PACKET DISTRIBUTION
> rxrpc_input_call_packet()
> rxrpc_input_data()
* QUEUE DATA PACKET ON CALL
> rxrpc_reduce_call_timer()
- Uses timer_reduce()
! Needs call->input_lock()
> rxrpc_receiving_reply()
! Needs locking around ack state
> rxrpc_rotate_tx_window()
> rxrpc_end_tx_phase()
> rxrpc_proto_abort()
> rxrpc_input_dup_data()
- Fills the Rx buffer
- rxrpc_propose_ACK()
- rxrpc_notify_socket()
> rxrpc_input_ack()
* APPLY ACK PACKET TO CALL AND DISCARD PACKET
> rxrpc_input_ping_response()
- Probably doesn't need any extra locking
! Need READ_ONCE() on call->ping_serial
> rxrpc_input_check_for_lost_ack()
- Takes call->lock to consult Tx buffer
> rxrpc_peer_add_rtt()
! Needs to take a lock (peer->rtt_input_lock)
! Could perhaps manage with cmpxchg() and xadd() instead
> rxrpc_input_requested_ack
- Consults Tx buffer
! Probably needs a lock
> rxrpc_peer_add_rtt()
> rxrpc_propose_ack()
> rxrpc_input_ackinfo()
- Changes call->tx_winsize
! Use cmpxchg to handle change
! Should perhaps track serial number
- Uses peer->lock to record MTU specification changes
> rxrpc_proto_abort()
! Need to take call->input_lock
> rxrpc_rotate_tx_window()
> rxrpc_end_tx_phase()
> rxrpc_input_soft_acks()
- Consults the Tx buffer
> rxrpc_congestion_management()
- Modifies the Tx annotations
! Needs call->input_lock()
> rxrpc_queue_call()
> rxrpc_input_abort()
* APPLY ABORT PACKET TO CALL AND DISCARD PACKET
> rxrpc_set_call_completion()
> rxrpc_notify_socket()
> rxrpc_input_ackall()
* APPLY ACKALL PACKET TO CALL AND DISCARD PACKET
! Need to take call->input_lock
> rxrpc_rotate_tx_window()
> rxrpc_end_tx_phase()
> rxrpc_reject_packet()
There are some functions used by the above that queue the packet, after
which the procedure is terminated:
- rxrpc_post_packet_to_local()
- local->event_queue is an sk_buff_head
- local->processor is a work_struct
- rxrpc_post_packet_to_conn()
- conn->rx_queue is an sk_buff_head
- conn->processor is a work_struct
- rxrpc_reject_packet()
- local->reject_queue is an sk_buff_head
- local->processor is a work_struct
And some that offload processing to process context:
- rxrpc_notify_socket()
- Uses RCU lock
- Uses call->notify_lock to call call->notify_rx
- Uses call->recvmsg_lock to queue recvmsg side
- rxrpc_queue_call()
- call->processor is a work_struct
- rxrpc_propose_ACK()
- Uses call->lock to wrap __rxrpc_propose_ACK()
And a bunch that complete a call, all of which use call->state_lock to
protect the call state:
- rxrpc_call_completed()
- rxrpc_set_call_completion()
- rxrpc_abort_call()
- rxrpc_proto_abort()
- Also uses rxrpc_queue_call()
Fixes: 17926a7932 ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: David Howells <dhowells@redhat.com>
Fix connection-level abort handling to cache the abort and error codes
properly so that a new incoming call can be properly aborted if it races
with the parent connection being aborted by another CPU.
The abort_code and error parameters can then be dropped from
rxrpc_abort_calls().
Fixes: f5c17aaeb2 ("rxrpc: Calls should only have one terminal state")
Signed-off-by: David Howells <dhowells@redhat.com>
Use the UDP encap_rcv hook to cut the bit out of the rxrpc packet reception
in which a packet is placed onto the UDP receive queue and then immediately
removed again by rxrpc. Going via the queue in this manner seems like it
should be unnecessary.
This does, however, require the invention of a value to place in encap_type
as that's one of the conditions to switch packets out to the encap_rcv
hook. Possibly the value doesn't actually matter for anything other than
sockopts on the UDP socket, which aren't accessible outside of rxrpc
anyway.
This seems to cut a bit of time out of the time elapsed between each
sk_buff being timestamped and turning up in rxrpc (the final number in the
following trace excerpts). I measured this by making the rxrpc_rx_packet
trace point print the time elapsed between the skb being timestamped and
the current time (in ns), e.g.:
... 424.278721: rxrpc_rx_packet: ... ACK 25026
So doing a 512MiB DIO read from my test server, with an unmodified kernel:
N min max sum mean stddev
27605 2626 7581 7.83992e+07 2840.04 181.029
and with the patch applied:
N min max sum mean stddev
27547 1895 12165 6.77461e+07 2459.29 255.02
Signed-off-by: David Howells <dhowells@redhat.com>
Fix some refs to init_net that should've been changed to the appropriate
network namespace.
Fixes: 2baec2c3f8 ("rxrpc: Support network namespacing")
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
rxrpc_extract_addr_from_skb() doesn't use the argument that points to the
local endpoint, so remove the argument.
Signed-off-by: David Howells <dhowells@redhat.com>
rxrpc_lose_skb() is now exactly the same as rxrpc_free_skb(), so remove it
and use the latter instead.
Signed-off-by: David Howells <dhowells@redhat.com>
Fix error distribution by immediately delivering the errors to all the
affected calls rather than deferring them to a worker thread. The problem
with the latter is that retries and things can happen in the meantime when we
want to stop that sooner.
To this end:
(1) Stop the error distributor from removing calls from the error_targets
list so that peer->lock isn't needed to synchronise against other adds
and removals.
(2) Require the peer's error_targets list to be accessed with RCU, thereby
avoiding the need to take peer->lock over distribution.
(3) Don't attempt to affect a call's state if it is already marked complete.
Signed-off-by: David Howells <dhowells@redhat.com>
Make the following changes to improve the robustness of the code that sets
up a new service call:
(1) Cache the rxrpc_sock struct obtained in rxrpc_data_ready() to do a
service ID check and pass that along to rxrpc_new_incoming_call().
This means that I can remove the check from rxrpc_new_incoming_call()
without the need to worry about the socket attached to the local
endpoint getting replaced - which would invalidate the check.
(2) Cache the rxrpc_peer struct, thereby allowing the peer search to be
done once. The peer is passed to rxrpc_new_incoming_call(), thereby
saving the need to repeat the search.
This also reduces the possibility of rxrpc_publish_service_conn()
BUG()'ing due to the detection of a duplicate connection, despite the
initial search done by rxrpc_find_connection_rcu() having turned up
nothing.
This BUG() shouldn't ever get hit since rxrpc_data_ready() *should* be
non-reentrant and the result of the initial search should still hold
true, but it has proven possible to hit.
I *think* this may be due to __rxrpc_lookup_peer_rcu() cutting short
the iteration over the hash table if it finds a matching peer with a
zero usage count, but I don't know for sure since it's only ever been
hit once that I know of.
Another possibility is that a bug in rxrpc_data_ready() that checked
the wrong byte in the header for the RXRPC_CLIENT_INITIATED flag
might've let through a packet that caused a spurious and invalid call
to be set up. That is addressed in another patch.
(3) Fix __rxrpc_lookup_peer_rcu() to skip peer records that have a zero
usage count rather than stopping and returning not found, just in case
there's another peer record behind it in the bucket.
(4) Don't search the peer records in rxrpc_alloc_incoming_call(), but
rather either use the peer cached in (2) or, if one wasn't found,
preemptively install a new one.
Fixes: 8496af50eb ("rxrpc: Use RCU to access a peer's service connection tree")
Signed-off-by: David Howells <dhowells@redhat.com>
In the input path, a received sk_buff can be marked for rejection by
setting RXRPC_SKB_MARK_* in skb->mark and, if needed, some auxiliary data
(such as an abort code) in skb->priority. The rejection is handled by
queueing the sk_buff up for dealing with in process context. The output
code reads the mark and priority and, theoretically, generates an
appropriate response packet.
However, if RXRPC_SKB_MARK_BUSY is set, this isn't noticed and an ABORT
message with a random abort code is generated (since skb->priority wasn't
set to anything).
Fix this by outputting the appropriate sort of packet.
Also, whilst we're at it, most of the marks are no longer used, so remove
them and rename the remaining two to something more obvious.
Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>
There's a check in rxrpc_data_ready() that's checking the CLIENT_INITIATED
flag in the packet type field rather than in the packet flags field.
Fix this by creating a pair of helper functions to check whether the packet
is going to the client or to the server and use them generally.
Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>
In the quest to remove all stack VLA usage from the kernel[1], this
replaces struct crypto_skcipher and SKCIPHER_REQUEST_ON_STACK() usage
with struct crypto_sync_skcipher and SYNC_SKCIPHER_REQUEST_ON_STACK(),
which uses a fixed stack size.
[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Cc: David Howells <dhowells@redhat.com>
Cc: linux-afs@lists.infradead.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
AF_RXRPC has a keepalive message generator that generates a message for a
peer ~20s after the last transmission to that peer to keep firewall ports
open. The implementation is incorrect in the following ways:
(1) It mixes up ktime_t and time64_t types.
(2) It uses ktime_get_real(), the output of which may jump forward or
backward due to adjustments to the time of day.
(3) If the current time jumps forward too much or jumps backwards, the
generator function will crank the base of the time ring round one slot
at a time (ie. a 1s period) until it catches up, spewing out VERSION
packets as it goes.
Fix the problem by:
(1) Only using time64_t. There's no need for sub-second resolution.
(2) Use ktime_get_seconds() rather than ktime_get_real() so that time
isn't perceived to go backwards.
(3) Simplifying rxrpc_peer_keepalive_worker() by splitting it into two
parts:
(a) The "worker" function that manages the buckets and the timer.
(b) The "dispatch" function that takes the pending peers and
potentially transmits a keepalive packet before putting them back
in the ring into the slot appropriate to the revised last-Tx time.
(4) Taking everything that's pending out of the ring and splicing it into
a temporary collector list for processing.
In the case that there's been a significant jump forward, the ring
gets entirely emptied and then the time base can be warped forward
before the peers are processed.
The warping can't happen if the ring isn't empty because the slot a
peer is in is keepalive-time dependent, relative to the base time.
(5) Limit the number of iterations of the bucket array when scanning it.
(6) Set the timer to skip any empty slots as there's no point waking up if
there's nothing to do yet.
This can be triggered by an incoming call from a server after a reboot with
AF_RXRPC and AFS built into the kernel causing a peer record to be set up
before userspace is started. The system clock is then adjusted by
userspace, thereby potentially causing the keepalive generator to have a
meltdown - which leads to a message like:
watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [kworker/0:1:23]
...
Workqueue: krxrpcd rxrpc_peer_keepalive_worker
EIP: lock_acquire+0x69/0x80
...
Call Trace:
? rxrpc_peer_keepalive_worker+0x5e/0x350
? _raw_spin_lock_bh+0x29/0x60
? rxrpc_peer_keepalive_worker+0x5e/0x350
? rxrpc_peer_keepalive_worker+0x5e/0x350
? __lock_acquire+0x3d3/0x870
? process_one_work+0x110/0x340
? process_one_work+0x166/0x340
? process_one_work+0x110/0x340
? worker_thread+0x39/0x3c0
? kthread+0xdb/0x110
? cancel_delayed_work+0x90/0x90
? kthread_stop+0x70/0x70
? ret_from_fork+0x19/0x24
Fixes: ace45bec6d ("rxrpc: Fix firewall route keepalive")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
