When an MTU update with PMTU smaller than net.ipv4.route.min_pmtu is
received, we must clamp its value. However, we can receive a PMTU
exception with PMTU < old_mtu < ip_rt_min_pmtu, which would lead to an
increase in PMTU.

To fix this, take the smallest of the old MTU and ip_rt_min_pmtu.

Before this patch, in case of an update, the exception's MTU would
always change. Now, an exception can have only its lock flag updated,
but not the MTU, so we need to add a check on locking to the following
"is this exception getting updated, or close to expiring?" test.

Fixes: d52e5a7e ("ipv4: lock mtu in fnhe when received PMTU < net.ipv4.route.min_pmtu")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Since commit 5aad1de5 ("ipv4: use separate genid for next hop
exceptions"), exceptions get deprecated separately from cached
routes. In particular, administrative changes don't clear PMTU anymore.

As Stefano described in commit e9fa1495 ("ipv6: Reflect MTU changes
on PMTU of exceptions for MTU-less routes"), the PMTU discovered before
the local MTU change can become stale:
 - if the local MTU is now lower than the PMTU, that PMTU is now
   incorrect
 - if the local MTU was the lowest value in the path, and is increased,
   we might discover a higher PMTU

Similarly to what commit e9fa1495 did for IPv6, update PMTU in those
cases.

If the exception was locked, the discovered PMTU was smaller than the
minimal accepted PMTU. In that case, if the new local MTU is smaller
than the current PMTU, let PMTU discovery figure out if locking of the
exception is still needed.

To do this, we need to know the old link MTU in the NETDEV_CHANGEMTU
notifier. By the time the notifier is called, dev->mtu has been
changed. This patch adds the old MTU as additional information in the
notifier structure, and a new call_netdevice_notifiers_u32() function.

Fixes: 5aad1de5 ("ipv4: use separate genid for next hop exceptions")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The fib6_info_alloc() function allocates percpu memory to hold per CPU
pointers to rt6_info, but this memory is never freed. Fix it.

Fixes: a64efe14 ("net/ipv6: introduce fib6_info struct and helpers")
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

David Howells says:

====================
rxrpc: Fix packet reception code

Here are a set of patches that prepares for and fix problems in rxrpc's
package reception code.  There serious problems are:

 (A) There's a window between binding the socket and setting the data_ready
     hook in which packets can find their way into the UDP socket's receive
     queues.

 (B) The skb_recv_udp() will return an error (and clear the error state) if
     there was an error on the Tx side.  rxrpc doesn't handle this.

 (C) The rxrpc data_ready handler doesn't fully drain the UDP receive
     queue.

 (D) The rxrpc data_ready handler assumes it is called in a non-reentrant
 state.

The second patch fixes (A) - (C); the third patch renders (B) and (C)
non-issues by using the recap_rcv hook instead of data_ready - and the
final patch fixes (D).  That last is the most complex.

The preparatory patches are:

 (1) Fix some places that are doing things in the wrong net namespace.

 (2) Stop taking the rcu read lock as it's held by the IP input routine in
     the call chain.

 (3) Only end the Tx phase if *we* rotated the final packet out of the Tx
     buffer.

 (4) Don't assume that the call state won't change after dropping the
     call_state lock.

 (5) Only take receive window and MTU suze parameters from an ACK packet if
     it's the latest ACK packet.

 (6) Record connection-level abort information correctly.

 (7) Fix a trace line.

And then there are three main patches - note that these are mixed in with
the preparatory patches somewhat:

 (1) Fix the setup window (A), skb_recv_udp() error check (B) and packet
     drainage (C).

 (2) Switch to using the encap_rcv instead of data_ready to cut out the
     effects of the UDP read queues and get the packets delivered directly.

 (3) Add more locking into the various packet input paths to defend against
     re-entrance (D).
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

In rds_send_mprds_hash(), if the calculated hash value is non-zero and
the MPRDS connections are not yet up, it will wait.  But it should not
wait if the send is non-blocking.  In this case, it should just use the
base c_path for sending the message.
Signed-off-by: Ka-Cheong Poon <ka-cheong.poon@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

syzbot managed to crash in skb_checksum_help() [1] :

        BUG_ON(offset + sizeof(__sum16) > skb_headlen(skb));

Root cause is the following check in skb_partial_csum_set()

	if (unlikely(start > skb_headlen(skb)) ||
	    unlikely((int)start + off > skb_headlen(skb) - 2))
		return false;

If skb_headlen(skb) is 1, then (skb_headlen(skb) - 2) becomes 0xffffffff
and the check fails to detect that ((int)start + off) is off the limit,
since the compare is unsigned.

When we fix that, then the first condition (start > skb_headlen(skb))
becomes obsolete.

Then we should also check that (skb_headroom(skb) + start) wont
overflow 16bit field.

[1]
kernel BUG at net/core/dev.c:2880!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 7330 Comm: syz-executor4 Not tainted 4.19.0-rc6+ #253
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:skb_checksum_help+0x9e3/0xbb0 net/core/dev.c:2880
Code: 85 00 ff ff ff 48 c1 e8 03 42 80 3c 28 00 0f 84 09 fb ff ff 48 8b bd 00 ff ff ff e8 97 a8 b9 fb e9 f8 fa ff ff e8 2d 09 76 fb <0f> 0b 48 8b bd 28 ff ff ff e8 1f a8 b9 fb e9 b1 f6 ff ff 48 89 cf
RSP: 0018:ffff8801d83a6f60 EFLAGS: 00010293
RAX: ffff8801b9834380 RBX: ffff8801b9f8d8c0 RCX: ffffffff8608c6d7
RDX: 0000000000000000 RSI: ffffffff8608cc63 RDI: 0000000000000006
RBP: ffff8801d83a7068 R08: ffff8801b9834380 R09: 0000000000000000
R10: ffff8801d83a76d8 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000010001 R14: 000000000000ffff R15: 00000000000000a8
FS:  00007f1a66db5700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7d77f091b0 CR3: 00000001ba252000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 skb_csum_hwoffload_help+0x8f/0xe0 net/core/dev.c:3269
 validate_xmit_skb+0xa2a/0xf30 net/core/dev.c:3312
 __dev_queue_xmit+0xc2f/0x3950 net/core/dev.c:3797
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3838
 packet_snd net/packet/af_packet.c:2928 [inline]
 packet_sendmsg+0x422d/0x64c0 net/packet/af_packet.c:2953

Fixes: 5ff8dda3 ("net: Ensure partial checksum offset is inside the skb head")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Moshe Shemesh says:

====================
devlink param type string fixes

This patchset fixes devlink param infrastructure for string param type.

The devlink param infrastructure doesn't handle copying the string data
correctly.  The first two patches fix it and the third patch adds helper
function to safely copy string value without exceeding
DEVLINK_PARAM_MAX_STRING_VALUE.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Devlink string param buffer is allocated at the size of
DEVLINK_PARAM_MAX_STRING_VALUE. Add helper function which makes sure
this size is not exceeded.
Renamed DEVLINK_PARAM_MAX_STRING_VALUE to
__DEVLINK_PARAM_MAX_STRING_VALUE to emphasize that it should be used by
devlink only. The driver should use the helper function instead to
verify it doesn't exceed the allowed length.
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Driverinit configuration mode value is held by devlink to enable the
driver fetch the value after reload command. In case the param type is
string devlink should copy the value from driver string buffer to
devlink string buffer on devlink_param_driverinit_value_set() and
vice-versa on devlink_param_driverinit_value_get().

Fixes: ec01aeb1 ("devlink: Add support for get/set driverinit value")
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In case devlink param type is string, it needs to copy the string value
it got from the input to devlink_param_value.

Fixes: e3b7ca18 ("devlink: Add param set command")
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Arthur Kiyanovski says:

====================
minor bug fixes for ENA Ethernet driver

Arthur Kiyanovski (4):
  net: ena: fix warning in rmmod caused by double iounmap
  net: ena: fix rare bug when failed restart/resume is followed by
    driver removal
  net: ena: fix NULL dereference due to untimely napi initialization
  net: ena: fix auto casting to boolean
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Eliminate potential auto casting compilation error.

Fixes: 1738cd3e ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)")
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

napi poll functions should be initialized before running request_irq(),
to handle a rare condition where there is a pending interrupt, causing
the ISR to fire immediately while the poll function wasn't set yet,
causing a NULL dereference.

Fixes: 1738cd3e ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)")
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In a rare scenario when ena_device_restore() fails, followed by device
remove, an FLR will not be issued. In this case, the device will keep
sending asynchronous AENQ keep-alive events, even after driver removal,
leading to memory corruption.

Fixes: 8c5c7abd ("net: ena: add power management ops to the ENA driver")
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Memory mapped with devm_ioremap is automatically freed when the driver
is disconnected from the device. Therefore there is no need to
explicitly call devm_iounmap.

Fixes: 0857d92f ("net: ena: add missing unmap bars on device removal")
Fixes: 411838e7 ("net: ena: fix rare kernel crash when bar memory remap fails")
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
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: 17926a79 ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: David Howells <dhowells@redhat.com>

Fix the rxrpc_tx_packet trace line by storing the where parameter.

Fixes: 4764c0da ("rxrpc: Trace packet transmission")
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: f5c17aae ("rxrpc: Calls should only have one terminal state")
Signed-off-by: David Howells <dhowells@redhat.com>

Move the out-of-order and duplicate ACK packet check to before the call to
rxrpc_input_ackinfo() so that the receive window size and MTU size are only
checked in the latest ACK packet and don't regress.

Fixes: 248f219c ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>

Carry the call state out of the locked section in rxrpc_rotate_tx_window()
rather than sampling it afterwards.  This is only used to select tracepoint
data, but could have changed by the time we do the tracepoint.
Signed-off-by: David Howells <dhowells@redhat.com>

We should only call the function to end a call's Tx phase if we rotated the
marked-last packet out of the transmission buffer.

Make rxrpc_rotate_tx_window() return an indication of whether it just
rotated the packet marked as the last out of the transmit buffer, carrying
the information out of the locked section in that function.

We can then check the return value instead of examining RXRPC_CALL_TX_LAST.

Fixes: 70790dbe ("rxrpc: Pass the last Tx packet marker in the annotation buffer")
Signed-off-by: David Howells <dhowells@redhat.com>

We don't need to take the RCU read lock in the rxrpc packet receive
function because it's held further up the stack in the IP input routine
around the UDP receive routines.

Fix this by dropping the RCU read lock calls from rxrpc_input_packet().
This simplifies the code.

Fixes: 70790dbe ("rxrpc: Pass the last Tx packet marker in the annotation buffer")
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>

Eugene Syromiatnikov says:

====================
net/smc: userspace breakage fixes

These two patches correct some userspace-affecting issues introduced
during 4.19 development cycle, specifically:
 * New structure "struct smcd_diag_dmbinfo" has been defined in a way
   that would lead to different layout of the structure on most 32-bit
   ABIs in comparison with layout on 64-bit ABIs;
 * One of the commits renamed an UAPI-exposed field name.

Changes since v1:
 * Managed not to forget to add --cover-letter.
 * Commit ID format in commit message has been changed in accordance
   with Sergei Shtylyov's recommendations.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit c601171d ("net/smc: provide smc mode in smc_diag.c") changed
the name of diag_fallback field of struct smc_diag_msg structure
to diag_mode.  However, this structure is a part of UAPI, and this change
breaks user space applications that use it ([1], for example).  Since
the new name is more suitable, convert the field to a union that provides
access to the data via both the new and the old name.

[1] https://gitlab.com/strace/strace/blob/v4.24/netlink_smc_diag.c#L165

Fixes: c601171d ("net/smc: provide smc mode in smc_diag.c")
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit 4b1b7d3b ("net/smc: add SMC-D diag support") introduced
new UAPI-exposed structure, struct smcd_diag_dmbinfo.  However,
it's not usable by compat binaries, as it has different layout there.
Probably, the most straightforward fix that will avoid similar issues
in the future is to use __aligned_u64 for 64-bit fields.

Fixes: 4b1b7d3b ("net/smc: add SMC-D diag support")
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

cls_u32.c misuses refcounts for struct tc_u_hnode - it counts references
via ->hlist and via ->tp_root together.  u32_destroy() drops the former
and, in case when there had been links, leaves the sucker on the list.
As the result, there's nothing to protect it from getting freed once links
are dropped.
That also makes the "is it busy" check incapable of catching the root
hnode - it *is* busy (there's a reference from tp), but we don't see it as
something separate.  "Is it our root?" check partially covers that, but
the problem exists for others' roots as well.

AFAICS, the minimal fix preserving the existing behaviour (where it doesn't
include oopsen, that is) would be this:
        * count tp->root and tp_c->hlist as separate references.  I.e.
have u32_init() set refcount to 2, not 1.
	* in u32_destroy() we always drop the former;
in u32_destroy_hnode() - the latter.

	That way we have *all* references contributing to refcount.  List
removal happens in u32_destroy_hnode() (called only when ->refcnt is 1)
an in u32_destroy() in case of tc_u_common going away, along with
everything reachable from it.  IOW, that way we know that
u32_destroy_key() won't free something still on the list (or pointed to by
someone's ->root).

Reproducer:

tc qdisc add dev eth0 ingress
tc filter add dev eth0 parent ffff: protocol ip prio 100 handle 1: \
u32 divisor 1
tc filter add dev eth0 parent ffff: protocol ip prio 200 handle 2: \
u32 divisor 1
tc filter add dev eth0 parent ffff: protocol ip prio 100 \
handle 1:0:11 u32 ht 1: link 801: offset at 0 mask 0f00 shift 6 \
plus 0 eat match ip protocol 6 ff
tc filter delete dev eth0 parent ffff: protocol ip prio 200
tc filter change dev eth0 parent ffff: protocol ip prio 100 \
handle 1:0:11 u32 ht 1: link 0: offset at 0 mask 0f00 shift 6 plus 0 \
eat match ip protocol 6 ff
tc filter delete dev eth0 parent ffff: protocol ip prio 100
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit 2276f58a ("udp: use a separate rx queue for packet reception")
turned static inline __skb_recv_udp() from being a trivial helper around
__skb_recv_datagram() into a UDP specific implementaion, making it
EXPORT_SYMBOL_GPL() at the same time.

There are external modules that got broken by __skb_recv_udp() not being
visible to them. Let's unbreak them by making __skb_recv_udp EXPORT_SYMBOL().

Rationale (one of those) why this is actually "technically correct" thing
to do: __skb_recv_udp() used to be an inline wrapper around
__skb_recv_datagram(), which itself (still, and correctly so, I believe)
is EXPORT_SYMBOL().

Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Eric Dumazet <edumazet@google.com>
Fixes: 2276f58a ("udp: use a separate rx queue for packet reception")
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

Dave writes:
  "Networking fixes:

  1) Fix truncation of 32-bit right shift in bpf, from Jann Horn.

  2) Fix memory leak in wireless wext compat, from Stefan Seyfried.

  3) Use after free in cfg80211's reg_process_hint(), from Yu Zhao.

  4) Need to cancel pending work when unbinding in smsc75xx otherwise
     we oops, also from Yu Zhao.

  5) Don't allow enslaving a team device to itself, from Ido Schimmel.

  6) Fix backwards compat with older userspace for rtnetlink FDB dumps.
     From Mauricio Faria.

  7) Add validation of tc policy netlink attributes, from David Ahern.

  8) Fix RCU locking in rawv6_send_hdrinc(), from Wei Wang."

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (26 commits)
  net: mvpp2: Extract the correct ethtype from the skb for tx csum offload
  ipv6: take rcu lock in rawv6_send_hdrinc()
  net: sched: Add policy validation for tc attributes
  rtnetlink: fix rtnl_fdb_dump() for ndmsg header
  yam: fix a missing-check bug
  net: bpfilter: Fix type cast and pointer warnings
  net: cxgb3_main: fix a missing-check bug
  bpf: 32-bit RSH verification must truncate input before the ALU op
  net: phy: phylink: fix SFP interface autodetection
  be2net: don't flip hw_features when VXLANs are added/deleted
  net/packet: fix packet drop as of virtio gso
  net: dsa: b53: Keep CPU port as tagged in all VLANs
  openvswitch: load NAT helper
  bnxt_en: get the reduced max_irqs by the ones used by RDMA
  bnxt_en: free hwrm resources, if driver probe fails.
  bnxt_en: Fix enables field in HWRM_QUEUE_COS2BW_CFG request
  bnxt_en: Fix VNIC reservations on the PF.
  team: Forbid enslaving team device to itself
  net/usb: cancel pending work when unbinding smsc75xx
  mlxsw: spectrum: Delete RIF when VLAN device is removed
  ...

* akpm:
  mm: madvise(MADV_DODUMP): allow hugetlbfs pages
  ocfs2: fix locking for res->tracking and dlm->tracking_list
  mm/vmscan.c: fix int overflow in callers of do_shrink_slab()
  mm/vmstat.c: skip NR_TLB_REMOTE_FLUSH* properly
  mm/vmstat.c: fix outdated vmstat_text
  proc: restrict kernel stack dumps to root
  mm/hugetlb: add mmap() encodings for 32MB and 512MB page sizes
  mm/migrate.c: split only transparent huge pages when allocation fails
  ipc/shm.c: use ERR_CAST() for shm_lock() error return
  mm/gup_benchmark: fix unsigned comparison to zero in __gup_benchmark_ioctl
  mm, thp: fix mlocking THP page with migration enabled
  ocfs2: fix crash in ocfs2_duplicate_clusters_by_page()
  hugetlb: take PMD sharing into account when flushing tlb/caches
  mm: migration: fix migration of huge PMD shared pages

Reproducer, assuming 2M of hugetlbfs available:

Hugetlbfs mounted, size=2M and option user=testuser

  # mount | grep ^hugetlbfs
  hugetlbfs on /dev/hugepages type hugetlbfs (rw,pagesize=2M,user=dan)
  # sysctl vm.nr_hugepages=1
  vm.nr_hugepages = 1
  # grep Huge /proc/meminfo
  AnonHugePages:         0 kB
  ShmemHugePages:        0 kB
  HugePages_Total:       1
  HugePages_Free:        1
  HugePages_Rsvd:        0
  HugePages_Surp:        0
  Hugepagesize:       2048 kB
  Hugetlb:            2048 kB

Code:

  #include <sys/mman.h>
  #include <stddef.h>
  #define SIZE 2*1024*1024
  int main()
  {
    void *ptr;
    ptr = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_HUGETLB | MAP_ANONYMOUS, -1, 0);
    madvise(ptr, SIZE, MADV_DONTDUMP);
    madvise(ptr, SIZE, MADV_DODUMP);
  }

Compile and strace:

  mmap(NULL, 2097152, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, -1, 0) = 0x7ff7c9200000
  madvise(0x7ff7c9200000, 2097152, MADV_DONTDUMP) = 0
  madvise(0x7ff7c9200000, 2097152, MADV_DODUMP) = -1 EINVAL (Invalid argument)

hugetlbfs pages have VM_DONTEXPAND in the VmFlags driver pages based on
author testing with analysis from Florian Weimer[1].

The inclusion of VM_DONTEXPAND into the VM_SPECIAL defination was a
consequence of the large useage of VM_DONTEXPAND in device drivers.

A consequence of [2] is that VM_DONTEXPAND marked pages are unable to be
marked DODUMP.

A user could quite legitimately madvise(MADV_DONTDUMP) their hugetlbfs
memory for a while and later request that madvise(MADV_DODUMP) on the same
memory.  We correct this omission by allowing madvice(MADV_DODUMP) on
hugetlbfs pages.

[1] https://stackoverflow.com/questions/52548260/madvisedodump-on-the-same-ptr-size-as-a-successful-madvisedontdump-fails-wit
[2] commit 0103bd16 ("mm: prepare VM_DONTDUMP for using in drivers")

Link: http://lkml.kernel.org/r/20180930054629.29150-1-daniel@linux.ibm.com
Link: https://lists.launchpad.net/maria-discuss/msg05245.html
Fixes: 0103bd16 ("mm: prepare VM_DONTDUMP for using in drivers")
Reported-by: Kenneth Penza <kpenza@gmail.com>
Signed-off-by: Daniel Black <daniel@linux.ibm.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In dlm_init_lockres() we access and modify res->tracking and
dlm->tracking_list without holding dlm->track_lock.  This can cause list
corruptions and can end up in kernel panic.

Fix this by locking res->tracking and dlm->tracking_list with
dlm->track_lock instead of dlm->spinlock.

Link: http://lkml.kernel.org/r/1529951192-4686-1-git-send-email-ashish.samant@oracle.comSigned-off-by: Ashish Samant <ashish.samant@oracle.com>
Reviewed-by: Changwei Ge <ge.changwei@h3c.com>
Acked-by: Joseph Qi <jiangqi903@gmail.com>
Acked-by: Jun Piao <piaojun@huawei.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <ge.changwei@h3c.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

do_shrink_slab() returns unsigned long value, and the placing into int
variable cuts high bytes off.  Then we compare ret and 0xfffffffe (since
SHRINK_EMPTY is converted to ret type).

Thus a large number of objects returned by do_shrink_slab() may be
interpreted as SHRINK_EMPTY, if low bytes of their value are equal to
0xfffffffe.  Fix that by declaration ret as unsigned long in these
functions.

Link: http://lkml.kernel.org/r/153813407177.17544.14888305435570723973.stgit@localhost.localdomainSigned-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reported-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

5dd0b16c ("mm/vmstat: Make NR_TLB_REMOTE_FLUSH_RECEIVED available even
on UP") made the availability of the NR_TLB_REMOTE_FLUSH* counters inside
the kernel unconditional to reduce #ifdef soup, but (either to avoid
showing dummy zero counters to userspace, or because that code was missed)
didn't update the vmstat_array, meaning that all following counters would
be shown with incorrect values.

This only affects kernel builds with
CONFIG_VM_EVENT_COUNTERS=y && CONFIG_DEBUG_TLBFLUSH=y && CONFIG_SMP=n.

Link: http://lkml.kernel.org/r/20181001143138.95119-2-jannh@google.com
Fixes: 5dd0b16c ("mm/vmstat: Make NR_TLB_REMOTE_FLUSH_RECEIVED available even on UP")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Kemi Wang <kemi.wang@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

7a9cdebd ("mm: get rid of vmacache_flush_all() entirely") removed the
VMACACHE_FULL_FLUSHES statistics, but didn't remove the corresponding
entry in vmstat_text.  This causes an out-of-bounds access in
vmstat_show().

Luckily this only affects kernels with CONFIG_DEBUG_VM_VMACACHE=y, which
is probably very rare.

Link: http://lkml.kernel.org/r/20181001143138.95119-1-jannh@google.com
Fixes: 7a9cdebd ("mm: get rid of vmacache_flush_all() entirely")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Kemi Wang <kemi.wang@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently, you can use /proc/self/task/*/stack to cause a stack walk on
a task you control while it is running on another CPU.  That means that
the stack can change under the stack walker.  The stack walker does
have guards against going completely off the rails and into random
kernel memory, but it can interpret random data from your kernel stack
as instruction pointers and stack pointers.  This can cause exposure of
kernel stack contents to userspace.

Restrict the ability to inspect kernel stacks of arbitrary tasks to root
in order to prevent a local attacker from exploiting racy stack unwinding
to leak kernel task stack contents.  See the added comment for a longer
rationale.

There don't seem to be any users of this userspace API that can't
gracefully bail out if reading from the file fails.  Therefore, I believe
that this change is unlikely to break things.  In the case that this patch
does end up needing a revert, the next-best solution might be to fake a
single-entry stack based on wchan.

Link: http://lkml.kernel.org/r/20180927153316.200286-1-jannh@google.com
Fixes: 2ec220e2 ("proc: add /proc/*/stack")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ken Chen <kenchen@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ARM64 architecture also supports 32MB and 512MB HugeTLB page sizes.  This
just adds mmap() system call argument encoding for them.

Link: http://lkml.kernel.org/r/1537841300-6979-1-git-send-email-anshuman.khandual@arm.comSigned-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

split_huge_page_to_list() fails on HugeTLB pages.  I was experimenting
with moving 32MB contig HugeTLB pages on arm64 (with a debug patch
applied) and hit the following stack trace when the kernel crashed.

[ 3732.462797] Call trace:
[ 3732.462835]  split_huge_page_to_list+0x3b0/0x858
[ 3732.462913]  migrate_pages+0x728/0xc20
[ 3732.462999]  soft_offline_page+0x448/0x8b0
[ 3732.463097]  __arm64_sys_madvise+0x724/0x850
[ 3732.463197]  el0_svc_handler+0x74/0x110
[ 3732.463297]  el0_svc+0x8/0xc
[ 3732.463347] Code: d1000400 f90b0e60 f2fbd5a2 a94982a1 (f9000420)

When unmap_and_move[_huge_page]() fails due to lack of memory, the
splitting should happen only for transparent huge pages not for HugeTLB
pages.  PageTransHuge() returns true for both THP and HugeTLB pages.
Hence the conditonal check should test PagesHuge() flag to make sure that
given pages is not a HugeTLB one.

Link: http://lkml.kernel.org/r/1537798495-4996-1-git-send-email-anshuman.khandual@arm.com
Fixes: 94723aaf ("mm: unclutter THP migration")
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This uses ERR_CAST() instead of an open-coded cast, as it is casting
across structure pointers, which upsets __randomize_layout:

ipc/shm.c: In function `shm_lock':
ipc/shm.c:209:9: note: randstruct: casting between randomized structure pointer types (ssa): `struct shmid_kernel' and `struct kern_ipc_perm'

  return (void *)ipcp;
         ^~~~~~~~~~~~

Link: http://lkml.kernel.org/r/20180919180722.GA15073@beast
Fixes: 82061c57 ("ipc: drop ipc_lock()")
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

get_user_pages_fast() will return negative value if no pages were pinned,
then be converted to a unsigned, which is compared to zero, giving the
wrong result.

Link: http://lkml.kernel.org/r/20180921095015.26088-1-yuehaibing@huawei.com
Fixes: 09e35a4a ("mm/gup_benchmark: handle gup failures")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>