Our customer encountered stuck NFS writes for blocks starting at specific
offsets w.r.t. page boundary caused by networking stack sending packets via
UFO enabled device with wrong checksum. The problem can be reproduced by
composing a long UDP datagram from multiple parts using MSG_MORE flag:

  sendto(sd, buff, 1000, MSG_MORE, ...);
  sendto(sd, buff, 1000, MSG_MORE, ...);
  sendto(sd, buff, 3000, 0, ...);

Assume this packet is to be routed via a device with MTU 1500 and
NETIF_F_UFO enabled. When second sendto() gets into __ip_append_data(),
this condition is tested (among others) to decide whether to call
ip_ufo_append_data():

  ((length + fragheaderlen) > mtu) || (skb && skb_is_gso(skb))

At the moment, we already have skb with 1028 bytes of data which is not
marked for GSO so that the test is false (fragheaderlen is usually 20).
Thus we append second 1000 bytes to this skb without invoking UFO. Third
sendto(), however, has sufficient length to trigger the UFO path so that we
end up with non-UFO skb followed by a UFO one. Later on, udp_send_skb()
uses udp_csum() to calculate the checksum but that assumes all fragments
have correct checksum in skb->csum which is not true for UFO fragments.

When checking against MTU, we need to add skb->len to length of new segment
if we already have a partially filled skb and fragheaderlen only if there
isn't one.

In the IPv6 case, skb can only be null if this is the first segment so that
we have to use headersize (length of the first IPv6 header) rather than
fragheaderlen (length of IPv6 header of further fragments) for skb == NULL.

Fixes: e89e9cf5 ("[IPv4/IPv6]: UFO Scatter-gather approach")
Fixes: e4c5e13a ("ipv6: Should use consistent conditional judgement for
	ip6 fragment between __ip6_append_data and ip6_finish_output")
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The 8000 series adapters uses catch-all filters for encapsulated traffic
to support filtering VXLAN, NVGRE and GENEVE traffic.
This new filter functionality requires a longer MCDI command.
This patch increases the size of buffers on stack that were missed, which
fixes a kernel panic from the stack protector.

Fixes: 9b410801 ("sfc: insert catch-all filters for encapsulated traffic")
Signed-off-by: Martin Habets <mhabets@solarflare.com>
Acked-by: Edward Cree <ecree@solarflare.com>
Acked-by: Bert Kenward bkenward@solarflare.com
Signed-off-by: David S. Miller <davem@davemloft.net>

This structure member is hidden behind CONFIG_SYSFS, and we
get a build error when that is disabled:

drivers/net/hyperv/netvsc_drv.c: In function 'netvsc_set_channels':
drivers/net/hyperv/netvsc_drv.c:754:49: error: 'struct net_device' has no member named 'num_rx_queues'; did you mean 'num_tx_queues'?
drivers/net/hyperv/netvsc_drv.c: In function 'netvsc_set_rxfh':
drivers/net/hyperv/netvsc_drv.c:1181:25: error: 'struct net_device' has no member named 'num_rx_queues'; did you mean 'num_tx_queues'?

As the value is only set once to the argument of alloc_netdev_mq(),
we can compare against that constant directly.

Fixes: ff4a4419 ("netvsc: allow get/set of RSS indirection table")
Fixes: 2b01888d ("netvsc: allow more flexible setting of number of channels")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The per netns loopback_dev->ip6_ptr is unregistered and set to
NULL when its mtu is set to smaller than IPV6_MIN_MTU, this
leads to that we could set rt->rt6i_idev NULL after a
rt6_uncached_list_flush_dev() and then crash after another
call.

In this case we should just bring its inet6_dev down, rather
than unregistering it, at least prior to commit 176c39af
("netns: fix addrconf_ifdown kernel panic") we always
override the case for loopback.

Thanks a lot to Andrey for finding a reliable reproducer.

Fixes: 176c39af ("netns: fix addrconf_ifdown kernel panic")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Daniel Lezcano <dlezcano@fr.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: David Ahern <dsahern@gmail.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Vladislav Yasevich says:

====================
macvlan: Fix some issues with changing mac addresses

There are some issues in macvlan wrt to changing it's mac address.
* An error is returned in the specified address is the same as an already
  assigned address.
* In passthru mode, the mac address of the macvlan device doesn't change.
* After changing the mac address of a passthru macvlan and then removing it,
  the mac address of the physical device remains changed.

This patch series attempts to resolve these issues.

V2: Address a small issue in p4 where we save the address from the lowerdev
    (from girish.moodalbail@oracle.com)
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Passthru macvlans directly change the mac address of the lower
level device.  That's OK, but after the macvlan is deleted,
the lower device is left with changed address and one needs to
reboot to bring back the origina HW addresses.

This scenario is actually quite common with passthru macvtap devices.

This patch attempts to solve this, by storing the mac address
of the lower device in macvlan_port structure and keeping track of
it through the changes.

After this patch, any changes to the lower device mac address
done trough the macvlan device, will be reverted back.  Any
changs done directly to the lower device mac address will be kept.
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Convert the port passthru boolean into flags with accesor functions.
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When a lower device of the passthru macvlan changes it's address,
passthru macvlan is supposed to change it's own address as well.
However, that doesn't happen correctly because the check in
macvlan_addr_busy() will catch the fact that the lower level
(port) mac address is the same as the address we are trying to
assign to the macvlan, and return an error.  As a reasult,
the address of the passthru macvlan device is never changed.

The same thing happens when the user attempts to change the
mac address of the passthru macvlan.

The simple solution appers to be to not check against
the lower device in case of passthru macvlan device, since
the 2 addresses are _supposed_ to be the same.
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The user currently gets an EBUSY error when attempting to set
the mac address on a macvlan device to the same value.

This should really be a no-op as nothing changes.  Catch
the condition and return early.
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add a flag to indicate if a queue is rate-limited. Test the flag in
NAPI poll handler and avoid rescheduling the queue if true, otherwise
we risk locking up the host. The rescheduling will be done in the
timer callback function.
Reported-by: Jean-Louis Dupond <jean-louis@dupond.be>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Tested-by: Jean-Louis Dupond <jean-louis@dupond.be>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There are number of problems with configuration peer
network device in absence of IFLA_VETH_PEER attributes
where attributes for main network device shared with
peer.

First it is not feasible to configure both network
devices with same MAC address since this makes
communication in such configuration problematic.

This case can be reproduced with following sequence:

  # ip link add address 02:11:22:33:44:55 type veth
  # ip li sh
  ...
  26: veth0@veth1: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc \
  noop state DOWN mode DEFAULT qlen 1000
      link/ether 00:11:22:33:44:55 brd ff:ff:ff:ff:ff:ff
  27: veth1@veth0: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc \
  noop state DOWN mode DEFAULT qlen 1000
      link/ether 00:11:22:33:44:55 brd ff:ff:ff:ff:ff:ff

Second it is not possible to register both main and
peer network devices with same name, that happens
when name for main interface is given with IFLA_IFNAME
and same attribute reused for peer.

This case can be reproduced with following sequence:

  # ip link add dev veth1a type veth
  RTNETLINK answers: File exists

To fix both of the cases check if corresponding netlink
attributes are taken from peer_tb when valid or
name based on rtnl ops kind and random address is used.
Signed-off-by: Serhey Popovych <serhe.popovych@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

cpsw driver tries to get macid for am43xx SoCs using the compatible
ti,am4372. But not all variants of am43x uses this complatible like
epos evm uses ti,am438x. So use a generic compatible ti,am43 to get
macid for all am43 based platforms.
Reviewed-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In commit 242d3a49 ("ipv6: reorder ip6_route_dev_notifier after ipv6_dev_notf")
I assumed NETDEV_REGISTER and NETDEV_UNREGISTER are paired,
unfortunately, as reported by jeffy, netdev_wait_allrefs()
could rebroadcast NETDEV_UNREGISTER event until all refs are
gone.

We have to add an additional check to avoid this corner case.
For netdev_wait_allrefs() dev->reg_state is NETREG_UNREGISTERED,
for dev_change_net_namespace(), dev->reg_state is
NETREG_REGISTERED. So check for dev->reg_state != NETREG_UNREGISTERED.

Fixes: 242d3a49 ("ipv6: reorder ip6_route_dev_notifier after ipv6_dev_notf")
Reported-by: jeffy <jeffy.chen@rock-chips.com>
Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The commit ("net/phy: micrel: Add workaround for bad autoneg") fixes an
autoneg failure case by resetting the hardware. This turns off
intterupts. Things will work themselves out if the phy polls, as it will
figure out it's state during a poll. However if the phy uses only
intterupts, the phy will stall, since interrupts are off. This patch
fixes the issue by calling config_intr after resetting the phy.

Fixes: d2fd719b ("net/phy: micrel: Add workaround for bad autoneg ")
Signed-off-by: Zach Brown <zach.brown@ni.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull networking fixes from David Miller:

 1) Fix refcounting wrt timers which hold onto inet6 address objects,
    from Xin Long.

 2) Fix an ancient bug in wireless wext ioctls, from Johannes Berg.

 3) Firmware handling fixes in brcm80211 driver, from Arend Van Spriel.

 4) Several mlx5 driver fixes (firmware readiness, timestamp cap
    reporting, devlink command validity checking, tc offloading, etc.)
    From Eli Cohen, Maor Dickman, Chris Mi, and Or Gerlitz.

 5) Fix dst leak in IP/IP6 tunnels, from Haishuang Yan.

 6) Fix dst refcount bug in decnet, from Wei Wang.

 7) Netdev can be double freed in register_vlan_device(). Fix from Gao
    Feng.

 8) Don't allow object to be destroyed while it is being dumped in SCTP,
    from Xin Long.

 9) Fix dpaa_eth build when modular, from Madalin Bucur.

10) Fix throw route leaks, from Serhey Popovych.

11) IFLA_GROUP missing from if_nlmsg_size() and ifla_policy[] table,
    also from Serhey Popovych.

12) Fix premature TX SKB free in stmmac, from Niklas Cassel.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (36 commits)
  igmp: add a missing spin_lock_init()
  net: stmmac: free an skb first when there are no longer any descriptors using it
  sfc: remove duplicate up_write on VF filter_sem
  rtnetlink: add IFLA_GROUP to ifla_policy
  ipv6: Do not leak throw route references
  dt-bindings: net: sms911x: Add missing optional VDD regulators
  dpaa_eth: reuse the dma_ops provided by the FMan MAC device
  fsl/fman: propagate dma_ops
  net/core: remove explicit do_softirq() from busy_poll_stop()
  fib_rules: Resolve goto rules target on delete
  sctp: ensure ep is not destroyed before doing the dump
  net/hns:bugfix of ethtool -t phy self_test
  net: 8021q: Fix one possible panic caused by BUG_ON in free_netdev
  cxgb4: notify uP to route ctrlq compl to rdma rspq
  ip6_tunnel: Correct tos value in collect_md mode
  decnet: always not take dst->__refcnt when inserting dst into hash table
  ip6_tunnel: fix potential issue in __ip6_tnl_rcv
  ip_tunnel: fix potential issue in ip_tunnel_rcv
  brcmfmac: fix uninitialized warning in brcmf_usb_probe_phase2()
  net/mlx5e: Avoid doing a cleanup call if the profile doesn't have it
  ...

Pull more pin control fixes from Linus Walleij:
 "Some late arriving fixes. I should have sent earlier, just swamped
  with work as usual. Thomas patch makes AMD systems usable despite
  firmware bugs so it is fairly important.

   - Make the AMD driver use a regular interrupt rather than a chained
     one, so the system does not lock up.

   - Fix a function call error deep inside the STM32 driver"

* tag 'pinctrl-v4.12-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
  pinctrl: stm32: Fix bad function call
  pinctrl/amd: Use regular interrupt instead of chained

Pull HID fixes from Jiri Kosina:

 - revert of a commit to magicmouse driver that regressess certain
   devices, from Daniel Stone

 - quirk for a specific Dell mouse, from Sebastian Parschauer

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
  Revert "HID: magicmouse: Set multi-touch keybits for Magic Mouse"
  HID: Add quirk for Dell PIXART OEM mouse

Pull livepatching fix from Jiri Kosina:
 "Fix the way how livepatches are being stacked with respect to RCU,
  from Petr Mladek"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
  livepatch: Fix stacking of patches with respect to RCU

Pull more ufs fixes from Al Viro:
 "More UFS fixes, unfortunately including build regression fix for the
  64-bit s_dsize commit. Fixed in this pile:

   - trivial bug in signedness of 32bit timestamps on ufs1

   - ESTALE instead of ufs_error() when doing open-by-fhandle on
     something deleted

   - build regression on 32bit in ufs_new_fragments() - calculating that
     many percents of u64 pulls libgcc stuff on some of those. Mea
     culpa.

   - fix hysteresis loop broken by typo in 2.4.14.7 (right next to the
     location of previous bug).

   - fix the insane limits of said hysteresis loop on filesystems with
     very low percentage of reserved blocks. If it's 5% or less, just
     use the OPTSPACE policy.

   - calculate those limits once and mount time.

  This tree does pass xfstests clean (both ufs1 and ufs2) and it _does_
  survive cross-builds.

  Again, my apologies for missing that, especially since I have noticed
  a related percentage-of-64bit issue in earlier patches (when dealing
  with amount of reserved blocks). Self-LART applied..."

* 'ufs-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  ufs: fix the logics for tail relocation
  ufs_iget(): fail with -ESTALE on deleted inode
  fix signedness of timestamps on ufs1

Fix expand_upwards() on architectures with an upward-growing stack (parisc,
metag and partly IA-64) to allow the stack to reliably grow exactly up to
the address space limit given by TASK_SIZE.
Signed-off-by: Helge Deller <deller@gmx.de>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Trinity gets kernel BUG at mm/mmap.c:1963! in about 3 minutes of
mmap testing.  That's the VM_BUG_ON(gap_end < gap_start) at the
end of unmapped_area_topdown().  Linus points out how MAP_FIXED
(which does not have to respect our stack guard gap intentions)
could result in gap_end below gap_start there.  Fix that, and
the similar case in its alternative, unmapped_area().

Cc: stable@vger.kernel.org
Fixes: 1be7107f ("mm: larger stack guard gap, between vmas")
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Debugged-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Andrey reported a lockdep warning on non-initialized
spinlock:

 INFO: trying to register non-static key.
 the code is fine but needs lockdep annotation.
 turning off the locking correctness validator.
 CPU: 1 PID: 4099 Comm: a.out Not tainted 4.12.0-rc6+ #9
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 Call Trace:
  __dump_stack lib/dump_stack.c:16
  dump_stack+0x292/0x395 lib/dump_stack.c:52
  register_lock_class+0x717/0x1aa0 kernel/locking/lockdep.c:755
  ? 0xffffffffa0000000
  __lock_acquire+0x269/0x3690 kernel/locking/lockdep.c:3255
  lock_acquire+0x22d/0x560 kernel/locking/lockdep.c:3855
  __raw_spin_lock_bh ./include/linux/spinlock_api_smp.h:135
  _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:175
  spin_lock_bh ./include/linux/spinlock.h:304
  ip_mc_clear_src+0x27/0x1e0 net/ipv4/igmp.c:2076
  igmpv3_clear_delrec+0xee/0x4f0 net/ipv4/igmp.c:1194
  ip_mc_destroy_dev+0x4e/0x190 net/ipv4/igmp.c:1736

We miss a spin_lock_init() in igmpv3_add_delrec(), probably
because previously we never use it on this code path. Since
we already unlink it from the global mc_tomb list, it is
probably safe not to acquire this spinlock here. It does not
harm to have it although, to avoid conditional locking.

Fixes: c38b7d32 ("igmp: acquire pmc lock for ip_mc_clear_src()")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'wireless-drivers-for-davem-2017-06-20' of git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/wireless-drivers

Kalle Valo says:

====================
wireless-drivers fixes for 4.12

Two important fixes for brcmfmac. The rest of the brcmfmac patches are
either code preparation and fixing a new build warning.

brcmfmac

* fix a NULL pointer dereference during resume

* fix a NULL pointer dereference with USB devices, a regression from
  v4.12-rc1
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

When having the skb pointer in the first descriptor, stmmac_tx_clean
can get called at a moment where the IP has only cleared the own bit
of the first descriptor, thus freeing the skb, even though there can
be several descriptors whose buffers point into the same skb.

By simply moving the skb pointer from the first descriptor to the last
descriptor, a skb will get freed only when the IP has cleared the
own bit of all the descriptors that are using that skb.
Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Somehow two copies of the line 'up_write(&vf->efx->filter_sem);' got into
 efx_ef10_sriov_set_vf_vlan().  This would put the mutex in a bad state and
 cause all subsequent down attempts to hang.

Fixes: 671b53ee ("sfc: Ensure down_write(&filter_sem) and up_write() are matched before calling efx_net_open()")
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Network interface groups support added while ago, however
there is no IFLA_GROUP attribute description in policy
and netlink message size calculations until now.

Add IFLA_GROUP attribute to the policy.

Fixes: cbda10fa ("net_device: add support for network device groups")
Signed-off-by: Serhey Popovych <serhe.popovych@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

While commit 73ba57bf ("ipv6: fix backtracking for throw routes")
does good job on error propagation to the fib_rules_lookup()
in fib rules core framework that also corrects throw routes
handling, it does not solve route reference leakage problem
happened when we return -EAGAIN to the fib_rules_lookup()
and leave routing table entry referenced in arg->result.

If rule with matched throw route isn't last matched in the
list we overwrite arg->result losing reference on throw
route stored previously forever.

We also partially revert commit ab997ad4 ("ipv6: fix the
incorrect return value of throw route") since we never return
routing table entry with dst.error == -EAGAIN when
CONFIG_IPV6_MULTIPLE_TABLES is on. Also there is no point
to check for RTF_REJECT flag since it is always set throw
route.

Fixes: 73ba57bf ("ipv6: fix backtracking for throw routes")
Signed-off-by: Serhey Popovych <serhe.popovych@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The lan911x family of devices require supplying from 3.3 V power
supplies (connected to VDD_IO, VDD_A and VREG_3.3 pins).  The existing
driver however obtains only VDD_IO and VDD_A regulators in an optional
way so document this in bindings.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Madalin Bucur says:

====================
net: fix loadable module for DPAA Ethernet

The DPAA Ethernet makes use of a symbol that is not exported.
Address the issue by propagating the dma_ops rather than calling
arch_setup_dma_ops().
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Remove the use of arch_setup_dma_ops() that was not exported
and was breaking loadable module compilation.
Signed-off-by: Madalin Bucur <madalin.bucur@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Make sure dma_ops are set, to be later used by the Ethernet driver.
Signed-off-by: Madalin Bucur <madalin.bucur@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Since commit 217f6974 ("net: busy-poll: allow preemption in
sk_busy_loop()") there is an explicit do_softirq() invocation after
local_bh_enable() has been invoked.
I don't understand why we need this because local_bh_enable() will
invoke do_softirq() once the softirq counter reached zero and we have
softirq-related work pending.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

We should avoid marking goto rules unresolved when their
target is actually reachable after rule deletion.

Consolder following sample scenario:

  # ip -4 ru sh
  0:      from all lookup local
  32000:  from all goto 32100
  32100:  from all lookup main
  32100:  from all lookup default
  32766:  from all lookup main
  32767:  from all lookup default

  # ip -4 ru del pref 32100 table main
  # ip -4 ru sh
  0:      from all lookup local
  32000:  from all goto 32100 [unresolved]
  32100:  from all lookup default
  32766:  from all lookup main
  32767:  from all lookup default

After removal of first rule with preference 32100 we
mark all goto rules as unreachable, even when rule with
same preference as removed one still present.

Check if next rule with same preference is available
and make all rules with goto action pointing to it.
Signed-off-by: Serhey Popovych <serhe.popovych@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rcu_read_(un)lock(), list_*_rcu(), and synchronize_rcu() are used for a secure
access and manipulation of the list of patches that modify the same function.
In particular, it is the variable func_stack that is accessible from the ftrace
handler via struct ftrace_ops and klp_ops.

Of course, it synchronizes also some states of the patch on the top of the
stack, e.g. func->transition in klp_ftrace_handler.

At the same time, this mechanism guards also the manipulation of
task->patch_state. It is modified according to the state of the transition and
the state of the process.

Now, all this works well as long as RCU works well. Sadly livepatching might
get into some corner cases when this is not true. For example, RCU is not
watching when rcu_read_lock() is taken in idle threads.  It is because they
might sleep and prevent reaching the grace period for too long.

There are ways how to make RCU watching even in idle threads, see
rcu_irq_enter(). But there is a small location inside RCU infrastructure when
even this does not work.

This small problematic location can be detected either before calling
rcu_irq_enter() by rcu_irq_enter_disabled() or later by rcu_is_watching().
Sadly, there is no safe way how to handle it.  Once we detect that RCU was not
watching, we might see inconsistent state of the function stack and the related
variables in klp_ftrace_handler(). Then we could do a wrong decision, use an
incompatible implementation of the function and break the consistency of the
system. We could warn but we could not avoid the damage.

Fortunately, ftrace has similar problems and they seem to be solved well there.
It uses a heavy weight implementation of some RCU operations. In particular, it
replaces:

  + rcu_read_lock() with preempt_disable_notrace()
  + rcu_read_unlock() with preempt_enable_notrace()
  + synchronize_rcu() with schedule_on_each_cpu(sync_work)

My understanding is that this is RCU implementation from a stone age. It meets
the core RCU requirements but it is rather ineffective. Especially, it does not
allow to batch or speed up the synchronize calls.

On the other hand, it is very trivial. It allows to safely trace and/or
livepatch even the RCU core infrastructure.  And the effectiveness is a not a
big issue because using ftrace or livepatches on productive systems is a rare
operation.  The safety is much more important than a negligible extra load.

Note that the alternative implementation follows the RCU principles. Therefore,
     we could and actually must use list_*_rcu() variants when manipulating the
     func_stack.  These functions allow to access the pointers in the right
     order and with the right barriers. But they do not use any other
     information that would be set only by rcu_read_lock().

Also note that there are actually two problems solved in ftrace:

First, it cares about the consistency of RCU read sections.  It is being solved
the way as described and used in this patch.

Second, ftrace needs to make sure that nobody is inside the dynamic trampoline
when it is being freed. For this, it also calls synchronize_rcu_tasks() in
preemptive kernel in ftrace_shutdown().

Livepatch has similar problem but it is solved by ftrace for free.
klp_ftrace_handler() is a good guy and never sleeps. In addition, it is
registered with FTRACE_OPS_FL_DYNAMIC. It causes that
unregister_ftrace_function() calls:

	* schedule_on_each_cpu(ftrace_sync) - always
	* synchronize_rcu_tasks() - in preemptive kernel

The effect is that nobody is neither inside the dynamic trampoline nor inside
the ftrace handler after unregister_ftrace_function() returns.

[jkosina@suse.cz: reformat changelog, fix comment]
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Setting these bits causes libinput to fail to initialize the device;
setting BTN_TOUCH and BTN_TOOL_FINGER causes it to treat the mouse as a
touchpad, and it then refuses to continue when it discovers ABS_X is not
set.

This breaks all known Wayland compositors, as well as Xorg when the
libinput driver is being used.

This reverts commit f4b65b95.
Signed-off-by: Daniel Stone <daniels@collabora.com>
Cc: Che-Liang Chiou <clchiou@chromium.org>
Cc: Thierry Escande <thierry.escande@collabora.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Pull clk fixes from Stephen Boyd:
 "One build fix for an Amlogic clk driver and a handful of Allwinner clk
  driver fixes for some DT bindings and a randconfig build error that
  all came in this merge window"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: sunxi-ng: a64: Export PLL_PERIPH0 clock for the PRCM
  clk: sunxi-ng: h3: Export PLL_PERIPH0 clock for the PRCM
  dt-bindings: clock: sunxi-ccu: Add pll-periph to PRCM's needed clocks
  clk: sunxi-ng: sun5i: Fix ahb_bist_clk definition
  clk: sunxi-ng: enable SUNXI_CCU_MP for PRCM
  clk: meson: gxbb: fix build error without RESET_CONTROLLER
  clk: sunxi-ng: v3s: Fix usb otg device reset bit
  clk: sunxi-ng: a31: Correct lcd1-ch1 clock register offset

Pull NTB fixes from Jon Mason:
 "NTB bug fixes to address the modinfo in ntb_perf, a couple of bugs in
  the NTB transport QP calculations, skx doorbells, and sleeping in
  ntb_async_tx_submit"

* tag 'ntb-4.12-bugfixes' of git://github.com/jonmason/ntb:
  ntb: no sleep in ntb_async_tx_submit
  ntb: ntb_hw_intel: Skylake doorbells should be 32bits, not 64bits
  ntb_transport: fix bug calculating num_qps_mw
  ntb_transport: fix qp count bug
  NTB: ntb_test: fix bug printing ntb_perf results
  ntb: Correct modinfo usage statement for ntb_perf

Now before dumping a sock in sctp_diag, it only holds the sock while
the ep may be already destroyed. It can cause a use-after-free panic
when accessing ep->asocs.

This patch is to set sctp_sk(sk)->ep NULL in sctp_endpoint_destroy,
and check if this ep is already destroyed before dumping this ep.
Suggested-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdrver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Do not sleep in ntb_async_tx_submit, which could deadlock.
This reverts commit "8c874cc1"

Fixes: 8c874cc1 ("NTB: Address out of DMA descriptor issue with NTB")
Reported-by: Jia-Ju Bai <baijiaju1990@163.com>
Signed-off-by: Allen Hubbe <Allen.Hubbe@dell.com>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>