err in bpf_prog_get_info_by_fd() still holds 0 at that time from prior
check_uarg_tail_zero() check. Explicitly return -EFAULT instead, so
user space can be notified of buggy behavior.

Fixes: 1e270976 ("bpf: Add BPF_OBJ_GET_INFO_BY_FD")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When an early demuxed packet reaches __udp6_lib_lookup_skb(), the
sk reference is retrieved and used, but the relevant reference
count is leaked and the socket destructor is never called.
Beyond leaking the sk memory, if there are pending UDP packets
in the receive queue, even the related accounted memory is leaked.

In the long run, this will cause persistent forward allocation errors
and no UDP skbs (both ipv4 and ipv6) will be able to reach the
user-space.

Fix this by explicitly accessing the early demux reference before
the lookup, and properly decreasing the socket reference count
after usage.

Also drop the skb_steal_sock() in __udp6_lib_lookup_skb(), and
the now obsoleted comment about "socket cache".

The newly added code is derived from the current ipv4 code for the
similar path.

v1 -> v2:
  fixed the __udp6_lib_rcv() return code for resubmission,
  as suggested by Eric
Reported-by: Sam Edwards <CFSworks@gmail.com>
Reported-by: Marc Haber <mh+netdev@zugschlus.de>
Fixes: 5425077d ("net: ipv6: Add early demux handler for UDP unicast")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

For SGMII/RGMII/QSGMII interfaces when physical link goes down
while traffic is high is resulting in underflow condition being set
on that specific BGX's LMAC. Which assets a backpresure and VNIC stops
transmitting packets.

This is due to BGX being disabled in link status change callback while
packet is in transit. This patch fixes this issue by not disabling BGX
but instead just disables packet Rx and Tx.
Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This reverts commit 809ecb9b. Since it
was reported to break vhost_net. We want to cache used event and use
it to check for notification. The assumption was that guest won't move
the event idx back, but this could happen in fact when 16 bit index
wraps around after 64K entries.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Saeed Mahameed says:

====================
Mellanox, mlx5 fixes 2017-07-27

This series contains some misc fixes to the mlx5 driver.

Please pull and let me know if there's any problem.

V1->V2:
 - removed redundant braces

for -stable:
4.7
net/mlx5: Fix command bad flow on command entry allocation failure

4.9
net/mlx5: Consider tx_enabled in all modes on remap
net/mlx5e: Fix outer_header_zero() check size

4.10
net/mlx5: Fix mlx5_add_flow_rules call with correct num of dests

4.11
net/mlx5: Fix mlx5_ifc_mtpps_reg_bits structure size
net/mlx5e: Add field select to MTPPS register
net/mlx5e: Fix broken disable 1PPS flow
net/mlx5e: Change 1PPS out scheme
net/mlx5e: Add missing support for PTP_CLK_REQ_PPS request
net/mlx5e: Fix wrong delay calculation for overflow check scheduling
net/mlx5e: Schedule overflow check work to mlx5e workqueue

4.12
net/mlx5: Fix command completion after timeout access invalid structure
net/mlx5e: IPoIB, Modify add/remove underlay QPN flows

I hope this is not too much, but most of the patches do apply cleanly on -stable.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

IPv6 tunnels use sizeof(struct in6_addr) as dev->addr_len,
but in many places especially bonding, we use struct sockaddr
to copy and set mac addr, this could lead to stack out-of-bounds
access.

Fix it by using a larger address storage like bonding.
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Historically, dev_ifsioc() uses struct sockaddr as mac
address definition, this is why dev_set_mac_address()
accepts a struct sockaddr pointer as input but now we
have various types of mac addresse whose lengths
are up to MAX_ADDR_LEN, longer than struct sockaddr,
and saved in dev->addr_len.

It is too late to fix dev_ifsioc() due to API
compatibility, so just reject those larger than
sizeof(struct sockaddr), otherwise we would read
and use some random bytes from kernel stack.

Fortunately, only a few IPv6 tunnel devices have addr_len
larger than sizeof(struct sockaddr) and they don't support
ndo_set_mac_addr(). But with team driver, in lb mode, they
can still be enslaved to a team master and make its mac addr
length as the same.

Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The driver attempts to 'select MDIO_DEVICE', but the code
is actually a loadable module when PHYLIB=m:

drivers/phy/broadcom/phy-bcm-ns-usb3.o: In function `bcm_ns_usb3_mdiodev_phy_write':
phy-bcm-ns-usb3.c:(.text.bcm_ns_usb3_mdiodev_phy_write+0x28): undefined reference to `mdiobus_write'
drivers/phy/broadcom/phy-bcm-ns-usb3.o: In function `bcm_ns_usb3_module_exit':
phy-bcm-ns-usb3.c:(.exit.text+0x18): undefined reference to `mdio_driver_unregister'
drivers/phy/broadcom/phy-bcm-ns-usb3.o: In function `bcm_ns_usb3_module_init':
phy-bcm-ns-usb3.c:(.init.text+0x18): undefined reference to `mdio_driver_register'
phy-bcm-ns-usb3.c:(.init.text+0x38): undefined reference to `mdio_driver_unregister'

Using 'depends on MDIO_BUS' instead will avoid the link error.

Fixes: af850e14 ("phy: bcm-ns-usb3: add MDIO driver using proper bus layer")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

I still see build errors in randconfig builds and have had this
patch for a while to locally work around it:

drivers/built-in.o: In function `xgene_mdio_probe':
mux-core.c:(.text+0x352154): undefined reference to `of_mdiobus_register'
mux-core.c:(.text+0x352168): undefined reference to `mdiobus_free'
mux-core.c:(.text+0x3521c0): undefined reference to `mdiobus_alloc_size'

The idea is that CONFIG_MDIO_BUS now reflects whether the mdio_bus
code is built-in or a module, and other drivers that use the core
code can simply depend on that, instead of having a complex
dependency line.

Fixes: 90eff909 ("net: phy: Allow splitting MDIO bus/device support from PHYs")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When adding ethtool steering rule with action DISCARD we wrongly
pass a NULL dest with dest_num 1 to mlx5_add_flow_rules().
What this error seems to have caused is sending VPORT 0
(MLX5_FLOW_DESTINATION_TYPE_VPORT) as the fte dest instead of no dests.
We have fte action correctly set to DROP so it might been ignored
anyways.

To reproduce use:
 # sudo ethtool --config-nfc <dev> flow-type ether \
   dst aa:bb:cc:dd:ee:ff action -1

Fixes: 74491de9 ("net/mlx5: Add multi dest support")
Signed-off-by: Paul Blakey <paulb@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

This is done in order to ensure that work will not run after the cleanup.

Fixes: ef9814de ('net/mlx5e: Add HW timestamping (TS) support')
Signed-off-by: Eugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

The overflow_period is calculated in seconds. In order to use it
for delayed work scheduling translation to jiffies is needed.

Fixes: ef9814de ('net/mlx5e: Add HW timestamping (TS) support')
Signed-off-by: Eugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

Add the missing option to enable the PTP_CLK_PPS function.
In this case pin should be configured as 1PPS IN first and
then it will be connected to PPS mechanism.
Events will be reported as PTP_CLOCK_PPSUSR events to relevant sysfs.

Fixes: ee7f1220 ('net/mlx5e: Implement 1PPS support')
Signed-off-by: Eugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

In order to fix the drift in 1PPS out need to adjust the next pulse.
On each 1PPS out falling edge driver gets the event, then the event
handler adjusts the next pulse starting time.

Fixes: ee7f1220 ('net/mlx5e: Implement 1PPS support')
Signed-off-by: Eugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

Need to disable the MTPPS and unsubscribe from the pulse events
when user disables the 1PPS functionality.

Fixes: ee7f1220 ('net/mlx5e: Implement 1PPS support')
Signed-off-by: Eugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

In order to mark relevant fields while setting the MTPPS register
add field select. Otherwise it can cause a misconfiguration in
firmware.

Fixes: ee7f1220 ('net/mlx5e: Implement 1PPS support')
Signed-off-by: Eugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

Fix miscalculation in reserved_at_1a0 field.

Fixes: ee7f1220 ('net/mlx5e: Implement 1PPS support')
Signed-off-by: Eugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

outer_header_zero() routine checks if the outer_headers match of a
flow-table entry are all zero.

This function uses the size of whole fte_match_param, instead of just
the outer_headers member, causing failure to detect all-zeros if
any other members of the fte_match_param are non-zero.

Use the correct size for zero check.

Fixes: 6dc6071c ("net/mlx5e: Add ethtool flow steering support")
Signed-off-by: Ilan Tayari <ilant@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

On interface remove, the clean-up was done incorrectly causing
an error in the log:
"SET_FLOW_TABLE_ROOT(0x92f) op_mod(0x0) failed...syndrome (0x7e9f14)"

This was caused by the following flow:
-ndo_uninit:
 Move QP state to RST (this disconnects the QP from FT),
 the QP cannot be attached to any FT unless it is in RTS.

-mlx5_rdma_netdev_free:
 cleanup_rx: Destroy FT
 cleanup_tx: Destroy QP and remove QPN from FT

This caused a problem when destroying current FT we tried to
re-attach the QP to the next FT which is not needed.

The correct flow is:
-mlx5_rdma_netdev_free:
	cleanup_rx: remove QPN from FT & Destroy FT
	cleanup_tx: Destroy QP

Fixes: 50854114 ("net/mlx5: Use underlay QPN from the root name space")
Signed-off-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

When driver fail to allocate an entry to send command to FW, it must
notify the calling function and release the memory allocated for
this command.

Fixes: e126ba97 ('mlx5: Add driver for Mellanox Connect-IB adapters')
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Cc: kernel-team@fb.com
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

Completion on timeout should not free the driver command entry structure
as it will need to access it again once real completion event from FW
will occur.

Fixes: 73dd3a48 ('net/mlx5: Avoid using pending command interface slots')
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Cc: kernel-team@fb.com
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

The tx_enabled lag event field is used to determine whether a slave is
active.
Current logic uses this value only if the mode is active-backup.

However, LACP mode, although considered a load balancing mode, can mark
a slave as inactive in certain situations (e.g., LACP timeout).

This fix takes the tx_enabled value into account when remapping, with
no respect to the LAG mode (this should not affect the behavior in XOR
mode, since in this mode both slaves are marked as active).

Fixes: 7907f23a (net/mlx5: Implement RoCE LAG feature)
Signed-off-by: Aviv Heller <avivh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

Upon sriov enable, eswitch is always enabled.
Currently, if enable hca failed over all VFs, we would skip eswitch
disable as part of sriov disable, which will lead to resources leak.

Fix it by disabling eswitch if it was enabled (use indication from
eswitch mode).

Fixes: 6b6adee3 ('net/mlx5: SRIOV core code refactoring')
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Noa Osherovich <noaos@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

Commit b1f5bfc2 ("sctp: don't dereference ptr before leaving
_sctp_walk_{params, errors}()") tried to fix the issue that it
may overstep the chunk end for _sctp_walk_{params, errors} with
'chunk_end > offset(length) + sizeof(length)'.

But it introduced a side effect: When processing INIT, it verifies
the chunks with 'param.v == chunk_end' after iterating all params
by sctp_walk_params(). With the check 'chunk_end > offset(length)
+ sizeof(length)', it would return when the last param is not yet
accessed. Because the last param usually is fwdtsn supported param
whose size is 4 and 'chunk_end == offset(length) + sizeof(length)'

This is a badly issue even causing sctp couldn't process 4-shakes.
Client would always get abort when connecting to server, due to
the failure of INIT chunk verification on server.

The patch is to use 'chunk_end <= offset(length) + sizeof(length)'
instead of 'chunk_end < offset(length) + sizeof(length)' for both
_sctp_walk_params and _sctp_walk_errors.

Fixes: b1f5bfc2 ("sctp: don't dereference ptr before leaving _sctp_walk_{params, errors}()")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In dccp_feat_init, when ccid_get_builtin_ccids failsto alloc
memory for rx.val, it should free tx.val before returning an
error.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The patch "dccp: fix a memleak that dccp_ipv6 doesn't put reqsk
properly" fixed reqsk refcnt leak for dccp_ipv6. The same issue
exists on dccp_ipv4.

This patch is to fix it for dccp_ipv4.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In dccp_v6_conn_request, after reqsk gets alloced and hashed into
ehash table, reqsk's refcnt is set 3. one is for req->rsk_timer,
one is for hlist, and the other one is for current using.

The problem is when dccp_v6_conn_request returns and finishes using
reqsk, it doesn't put reqsk. This will cause reqsk refcnt leaks and
reqsk obj never gets freed.

Jianlin found this issue when running dccp_memleak.c in a loop, the
system memory would run out.

dccp_memleak.c:
  int s1 = socket(PF_INET6, 6, IPPROTO_IP);
  bind(s1, &sa1, 0x20);
  listen(s1, 0x9);
  int s2 = socket(PF_INET6, 6, IPPROTO_IP);
  connect(s2, &sa1, 0x20);
  close(s1);
  close(s2);

This patch is to put the reqsk before dccp_v6_conn_request returns,
just as what tcp_conn_request does.
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The buffer passed to bpf_obj_get_info_by_fd() should be initialized
to zeros.  Kernel will enforce that to guarantee we can safely extend
info structures in the future.

Making the bpf_obj_get_info_by_fd() call in libbpf perform the zeroing
is problematic, however, since some members of the info structures
may need to be initialized by the callers (for instance pointers
to buffers to which kernel is to dump translated and jited images).

Remove the zeroing and fix up the in-tree callers before any kernel
has been released with this code.

As Daniel points out this seems to be the intended operation anyway,
since commit 95b9afd3 ("bpf: Test for bpf ID") is itself setting
the buffer pointers before calling bpf_obj_get_info_by_fd().
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Apparently netpoll_setup() assumes that netpoll.dev_name is a pointer
when checking if the device name is set:

if (np->dev_name) {
  ...

However the field is a character array, therefore the condition always
yields true. Check instead whether the first byte of the array has a
non-zero value.
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit de77ecd4 ("bonding: improve link-status update in mii-monitoring")
moves link status commitment into bond_mii_monitor(), but it still relies
on the return value of bond_miimon_inspect() as the hint. We need to return
non-zero as long as we propose a link status change.

Fixes: de77ecd4 ("bonding: improve link-status update in mii-monitoring")
Reported-by: Benjamin Gilbert <benjamin.gilbert@coreos.com>
Tested-by: Benjamin Gilbert <benjamin.gilbert@coreos.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We must use pre-processor conditional block or suitable accessors to
manipulate skb->sp elsewhere builds lacking the CONFIG_XFRM will break.

Fixes: dce4551c ("udp: preserve head state for IP_CMSG_PASSSEC")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Before commit bf8f6952 ("Add blurb about RGMII") it was unclear
whose responsibility it was to insert the required clock skew, and
in hindsight, some PHY drivers got it wrong. The solution forward
is to introduce a new property, explicitly requiring skew from the
node to which it is attached. In the interim, this driver will handle
all 4 RGMII modes identically (no skew).

Fixes: 52dfc830 ("net: ethernet: add driver for Aurora VLSI NB8800 Ethernet controller")
Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The logic for computing page buffer scatter does not take into
account the impact of compound pages. Therefore the optimization
to compute number of slots was incorrect and could cause stack
corruption a skb was sent with lots of fragments from huge pages.

This reverts commit 60b86665.

Fixes: 60b86665 ("netvsc: optimize calculation of number of slots")
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The error paths set err, but it's not returned.

I wondered if we should fix all of the callers to check the returned
value, but Ben explains why the code is this way:

> Most call sites ignore it on purpose. There's nothing we can do if
> we fail to get a buffer at interrupt time, so we point the buffer to
> the scratch page so the HW doesn't DMA into lalaland and lose the
> packet.
>
> The one call site that tests and can fail is the one used when brining
> the interface up. If we fail to allocate at that point, we fail the
> ifup. But as you noticed, I do have a bug not returning the error.
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

RFC 2465 defines ipv6IfStatsOutFragFails as:

	"The number of IPv6 datagrams that have been discarded
	 because they needed to be fragmented at this output
	 interface but could not be."

The existing implementation, instead, would increase the counter
twice in case we fail to allocate room for single fragments:
once for the fragment, once for the datagram.

This didn't look intentional though. In one of the two affected
affected failure paths, the double increase was simply a result
of a new 'goto fail' statement, introduced to avoid a skb leak.
The other path appears to be affected since at least 2.6.12-rc2.
Reported-by: Sabrina Dubroca <sdubroca@redhat.com>
Fixes: 1d325d21 ("ipv6: ip6_fragment: fix headroom tests and skb leak")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

I forgot one spot when introducing struct test_obj_val.

Fixes: e859afe1 ("lib: test_rhashtable: fix for large entry counts")
Reported by: kernel test robot <fengguang.wu@intel.com>
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit e5a03bfd ("phy: Add an mdio_device structure")
introduced a spurious trailing semicolon. Remove it.
Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Paul Moore reported a SELinux/IP_PASSSEC regression
caused by missing skb->sp at recvmsg() time. We need to
preserve the skb head state to process the IP_CMSG_PASSSEC
cmsg.

With this commit we avoid releasing the skb head state in the
BH even if a secpath is attached to the current skb, and stores
the skb status (with/without head states) in the scratch area,
so that we can access it at skb deallocation time, without
incurring in cache-miss penalties.

This also avoids misusing the skb CB for ipv6 packets,
as introduced by the commit 0ddf3fb2 ("udp: preserve
skb->dst if required for IP options processing").

Clean a bit the scratch area helpers implementation, to
reduce the code differences between 32 and 64 bits build.
Reported-by: Paul Moore <paul@paul-moore.com>
Fixes: 0a463c78 ("udp: avoid a cache miss on dequeue")
Fixes: 0ddf3fb2 ("udp: preserve skb->dst if required for IP options processing")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Tested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The mt7530 driver has its dsa_switch_ops::get_tag_protocol function
check ds->cpu_port_mask to issue a warning in case the configured CPU
port is not capable of supporting tags.

After commit 14be36c2 ("net: dsa: Initialize all CPU and enabled
ports masks in dsa_ds_parse()") we slightly re-arranged the
initialization such that this was no longer working. Just make sure that
ds->cpu_port_mask is set prior to the first call to get_tag_protocol,
thus restoring the expected contract. In case of error, the CPU port bit
is cleared.

Fixes: 14be36c2 ("net: dsa: Initialize all CPU and enabled ports masks in dsa_ds_parse()")
Reported-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There are multiple reports showing we have a use-after-free in
the timer prb_retire_rx_blk_timer_expired(), where we use struct
tpacket_kbdq_core::pkbdq, a pg_vec, after it gets freed by
free_pg_vec().

The interesting part is it is not freed via packet_release() but
via packet_setsockopt(), which means we are not closing the socket.
Looking into the big and fat function packet_set_ring(), this could
happen if we satisfy the following conditions:

1. closing == 0, not on packet_release() path
2. req->tp_block_nr == 0, we don't allocate a new pg_vec
3. rx_ring->pg_vec is already set as V3, which means we already called
   packet_set_ring() wtih req->tp_block_nr > 0 previously
4. req->tp_frame_nr == 0, pass sanity check
5. po->mapped == 0, never called mmap()

In this scenario we are clearing the old rx_ring->pg_vec, so we need
to free this pg_vec, but we don't stop the timer on this path because
of closing==0.

The timer has to be stopped as long as we need to free pg_vec, therefore
the check on closing!=0 is wrong, we should check pg_vec!=NULL instead.

Thanks to liujian for testing different fixes.

Reported-by: alexander.levin@verizon.com
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Reported-by: liujian (CE) <liujian56@huawei.com>
Tested-by: liujian (CE) <liujian56@huawei.com>
Cc: Ding Tianhong <dingtianhong@huawei.com>
Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>