md/raid1: consider WRITE as successful only if at least one non-Faulty and non-rebuilding drive completed it.

Without that fix, the following scenario could happen:

- RAID1 with drives A and B; drive B was freshly-added and is rebuilding
- Drive A fails
- WRITE request arrives to the array. It is failed by drive A, so
r1_bio is marked as R1BIO_WriteError, but the rebuilding drive B
succeeds in writing it, so the same r1_bio is marked as
R1BIO_Uptodate.
- r1_bio arrives to handle_write_finished, badblocks are disabled,
md_error()->error() does nothing because we don't fail the last drive
of raid1
- raid_end_bio_io()  calls call_bio_endio()
- As a result, in call_bio_endio():
        if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
                clear_bit(BIO_UPTODATE, &bio->bi_flags);
this code doesn't clear the BIO_UPTODATE flag, and the whole master
WRITE succeeds, back to the upper layer.

So we returned success to the upper layer, even though we had written
the data onto the rebuilding drive only. But when we want to read the
data back, we would not read from the rebuilding drive, so this data
is lost.

[neilb - applied identical change to raid10 as well]

This bug can result in lost data, so it is suitable for any
-stable kernel.

Cc: stable@vger.kernel.org
Signed-off-by: Alex Lyakas <alex@zadarastorage.com>
Signed-off-by: NeilBrown <neilb@suse.de>

__md_stop_writes() will currently sometimes freeze recovery.
So any caller must be ready for that to happen, and indeed they are.

However if __md_stop_writes() doesn't freeze_recovery, then
a recovery could start before mddev_suspend() is called, which
could be awkward.  This can particularly cause problems or dm-raid.

So change __md_stop_writes() to always freeze recovery.  This is safe
and more predicatable.
Reported-by: Brassow Jonathan <jbrassow@redhat.com>
Tested-by: Brassow Jonathan <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

In SSD/hard disk hybid storage, discard request should be ignored for hard
disk. We used to be doing this way, but the unplug path forgets it.

This is suitable for stable tree since v3.6.

Cc: stable@vger.kernel.org
Reported-and-tested-by: Markus <M4rkusXXL@web.de>
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>

Maintenance of a bad-block-list currently defaults to 'enabled'
and is then disabled when it cannot be supported.
This is backwards and causes problem for dm-raid which didn't know
to disable it.

So fix the defaults, and only enabled for v1.x metadata which
explicitly has bad blocks enabled.

The problem with dm-raid has been present since badblock support was
added in v3.1, so this patch is suitable for any -stable from 3.1
onwards.

Cc: stable@vger.kernel.org (3.1+)
Reported-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

Hi.

Raid1 and raid10 devices leak memory every time they stop.
This is a patch for linux-3.9.0-rc7 to fix this problem.

Thanks,
Hirokazu Takahashi.
Signed-off-by: Hirokazu Takahashi <taka@valinux.co.jp>
Signed-off-by: NeilBrown <neilb@suse.de>

DM RAID:  Add message/status support for changing sync action

This patch adds a message interface to dm-raid to allow the user to more
finely control the sync actions being performed by the MD driver.  This
gives the user the ability to initiate "check" and "repair" (i.e. scrubbing).
Two additional fields have been appended to the status output to provide more
information about the type of sync action occurring and the results of those
actions, specifically: <sync_action> and <mismatch_cnt>.  These new fields
will always be populated.  This is essentially the device-mapper way of doing
what MD controls through the 'sync_action' sysfs file and shows through the
'mismatch_cnt' sysfs file.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

MD: Export 'md_reap_sync_thread' function

Make 'md_reap_sync_thread' available to other files, specifically dm-raid.c.
- rename reap_sync_thread to md_reap_sync_thread
- move the fn after md_check_recovery to match md.h declaration placement
- export md_reap_sync_thread
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

read-only arrays should stay that way as much as possible.
Updating the metadata - which could be triggered by a re-add
while assembling the array metadata - should be avoided.
Signed-off-by: NeilBrown <neilb@suse.de>

When assembling an array incrementally we might want to make
it device available when "enough" devices are present, but maybe
not "all" devices are present.
If the remaining devices appear before the array is actually used,
they should be added transparently.

We do this by using the "read-auto" mode where the array acts like
it is read-only until a write request arrives.

Current an add-device request switches a read-auto array to active.
This means that only one device can be added after the array is first
made read-auto.  This isn't a problem for RAID5, but is not ideal for
RAID6 or RAID10.
Also we don't really want to switch the array to read-auto at all
when re-adding a device as this doesn't really imply any change.

So:
 - remove the "md_update_sb()" call from add_new_disk().  This isn't
   really needed as just adding a disk doesn't require a metadata
   update.  Instead, just set MD_CHANGE_DEVS.  This will effect a
   metadata update soon enough, once the array is not read-only.

 - Allow the ADD_NEW_DISK ioctl to succeed without activating a
   read-auto array, providing the MD_DISK_SYNC flag is set.
   In this case, the device will be rejected if it cannot be added
   with the correct device number, or has an incorrect event count.

 - Teach remove_and_add_spares() to be careful about adding spares
   when the array is read-only (or read-mostly) - only add devices
   that are thought to be in-sync, and only do it if the array is
   in-sync itself.

 - In md_check_recovery, use remove_and_add_spares in the read-only
   case, rather than open coding just the 'remove' part of it.
Reported-by: Martin Wilck <mwilck@arcor.de>
Signed-off-by: NeilBrown <neilb@suse.de>

When an array is assembled incrementally with mdadm -I -R
and the array switches to "active" mode, md starts a recovery.

If the array was clean, the "fullsync" flag will be 0. Skip
the full recovery in this case, as RAID1 does (the code was
actually copied from the sync_request() method of RAID1).
Signed-off-by: Martin Wilck <mwilck@arcor.de>
Signed-off-by: NeilBrown <neilb@suse.de>

MD:  Fix some typos/grammer in MD documentation
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

If we write to a known-bad-block it will be flags as having
a ReadError by analyse_stripe, but the write will proceed anyway
(as it should).  Then the read-error handling will kick in an
write again, then re-read.

We don't need that 'write-again', so set R5_ReWrite so it looks like
it has already been done.  Then we will just get the re-read, which we
want.
Reported-by: majianpeng <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>

As the function call is the most expensive of these tests it should be
done later in the chain so that it can be avoided in some cases.
Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>

The value returned by test_and_set_bit_le() drivers/md/bitmap.c is not used.
So just use set_bit_le(). The same goes for test_and_clear_bit_le().
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>

If a fail device or a spare is removed from an array, there is
not need to make the array 'active'.  If/when the array does become
active for some other reason the metadata will be update to reflect
the removal.
If that never happens and the array is stopped while still read-auto,
then there is no loss in forgetting the that the device had 'failed'.

A read-only array will leave failed devices attached to
the array personality, so we need to explicitly call
remove_and_add_spares() to free it (clearing Blocked just
like we do in store_slot()).
Signed-off-by: NeilBrown <neilb@suse.de>

slot_store and remove_and_add_spares both call ->hot_remove_disk(),
but with slightly different tests and consequences, which is
at least untidy and might be buggy.

So modify remove_and_add_spaces() so that it can be asked
to remove a specific device, and call it from slot_store().

We also clear the Blocked flag to ensure that doesn't prevent
removal.  The purpose of Blocked is to prevent automatic removal
by the kernel before an error is acknowledged.
If the array is read/write then user-space would have not reason
to remove a device unless it was known to be 'spare' or 'faulty' in
which it would have already cleared the Blocked flag.
If the array is read-only, the flag might still be blocked, but
there is no harm in clearing the flag for read-only arrays.
Signed-off-by: NeilBrown <neilb@suse.de>

Normally we don't even try to update the metadata if
the array is read-only.  However future patches
will increase the number of things that can happen on a read-only
array, so it is safest to explicitly disable this.

Every time that mddev->ro is set to 0, either
 - md_update_sb will be called again (at least if MD_CHANGE_DEVS
   is set) or
 - the mddev->thread is scheduled, which will also run
   md_update_sb if needed.

So this is safe: if the array ever become read-write the
metadata will be updated.
Signed-off-by: NeilBrown <neilb@suse.de>

Pull MIPS fix from Ralf Baechle:
 "Revert the change of the definition of PAGE_MASK which was prettier
  but broke a few relativly rare platforms"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  Revert "MIPS: page.h: Provide more readable definition for PAGE_MASK."

This reverts commit c17a6554.

Manuel Lauss writes:

lmo commit c17a6554 (MIPS: page.h: Provide more readable definition for
PAGE_MASK) apparently breaks ioremap of 36-bit addresses on my Alchemy
systems (PCI and PCMCIA) The reason is that in arch/mips/mm/ioremap.c
line 157  (phys_addr &= PAGE_MASK) bits 32-35 are cut off.  Seems the
new PAGE_MASK is explicitly 32bit, or one could make it signed instead
of unsigned long.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull crypto fix from Herbert Xu:
 "This fixes a kernel memory leak in the algif interface"

* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: algif - suppress sending source address information in recvmsg

Pull perf fixes from Ingo Molnar:
 "Misc fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86: Fix offcore_rsp valid mask for SNB/IVB
  perf: Treat attr.config as u64 in perf_swevent_init()

I'm going to do an -rc8, so I'm just going to do this rather than delay
it any further. They are arguably stable material anyway.

* vm_ioremap_memory-examples:
  mtdchar: remove no-longer-used vma helpers
  vm: convert snd_pcm_lib_mmap_iomem() to vm_iomap_memory() helper
  vm: convert fb_mmap to vm_iomap_memory() helper
  vm: convert mtdchar mmap to vm_iomap_memory() helper
  vm: convert HPET mmap to vm_iomap_memory() helper

Pull kdump fixes from Peter Anvin:
 "The kexec/kdump people have found several problems with the support
  for loading over 4 GiB that was introduced in this merge cycle.  This
  is partly due to a number of design problems inherent in the way the
  various pieces of kdump fit together (it is pretty horrifically manual
  in many places.)

  After a *lot* of iterations this is the patchset that was agreed upon,
  but of course it is now very late in the cycle.  However, because it
  changes both the syntax and semantics of the crashkernel option, it
  would be desirable to avoid a stable release with the broken
  interfaces."

I'm not happy with the timing, since originally the plan was to release
the final 3.9 tomorrow.  But apparently I'm doing an -rc8 instead...

* 'x86-kdump-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kexec: use Crash kernel for Crash kernel low
  x86, kdump: Change crashkernel_high/low= to crashkernel=,high/low
  x86, kdump: Retore crashkernel= to allocate under 896M
  x86, kdump: Set crashkernel_low automatically

Pull x86 fixes from Peter Anvin:
 "Three groups of fixes:

   1. Make sure we don't execute the early microcode patching if family
      < 6, since it would touch MSRs which don't exist on those
      families, causing crashes.

   2. The Xen partial emulation of HyperV can be dealt with more
      gracefully than just disabling the driver.

   3. More EFI variable space magic.  In particular, variables hidden
      from runtime code need to be taken into account too."

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, microcode: Verify the family before dispatching microcode patching
  x86, hyperv: Handle Xen emulation of Hyper-V more gracefully
  x86,efi: Implement efi_no_storage_paranoia parameter
  efi: Export efi_query_variable_store() for efivars.ko
  x86/Kconfig: Make EFI select UCS2_STRING
  efi: Distinguish between "remaining space" and actually used space
  efi: Pass boot services variable info to runtime code
  Move utf16 functions to kernel core and rename
  x86,efi: Check max_size only if it is non-zero.
  x86, efivars: firmware bug workarounds should be in platform code

Pull ARM fixes from Russell King:
 "A set of fixes from various people - Will Deacon gets a prize for
  removing code this time around.  The biggest fix in this lot is
  sorting out the ARM740T mess.  The rest are relatively small fixes."

* 'fixes' of git://git.linaro.org/people/rmk/linux-arm:
  ARM: 7699/1: sched_clock: Add more notrace to prevent recursion
  ARM: 7698/1: perf: fix group validation when using enable_on_exec
  ARM: 7697/1: hw_breakpoint: do not use __cpuinitdata for dbg_cpu_pm_nb
  ARM: 7696/1: Fix kexec by setting outer_cache.inv_all for Feroceon
  ARM: 7694/1: ARM, TCM: initialize TCM in paging_init(), instead of setup_arch()
  ARM: 7692/1: iop3xx: move IOP3XX_PERIPHERAL_VIRT_BASE
  ARM: modules: don't export cpu_set_pte_ext when !MMU
  ARM: mm: remove broken condition check for v4 flushing
  ARM: mm: fix numerous hideous errors in proc-arm740.S
  ARM: cache: remove ARMv3 support code
  ARM: tlbflush: remove ARMv3 support

Pull sparc fixes from David Miller:

 1) Fix race in sparc64 TLB shootdowns, we have to synchronize with the
    sibling cpus completing if we are passing them a reference via
    pointer to a data structure.

 2) Fix cleaning of bitmaps in sparc32, from Akinobu Mita.

 3) Fix various sparc header mistakes, some of which resulted in
    userland build breakage.  From Sam Ravnborg.

 4) Kill ghost declarations and defines missed when several bits of code
    got deleted recently.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sparc64: Fix race in TLB batch processing.
  sparc: use asm-generic version of types.h
  bbc_i2c: fix section mismatch warning
  sparc: use generic headers
  sparc:cleanup unused code in smp_32.h
  sparc/iommu: fix typo s/265KB/256KB/
  sparc/srmmu: clear trailing edge of bitmap properly
  sparc:remove unused declaration smp_boot_cpus()

Pull networking updates from David Miller:

 1) ax88796 does 64-bit divides which causes link errors on ARM, fix
    from Arnd Bergmann.

 2) Once an improper offload setting is detected on an SKB we don't rate
    limit the log message so we can very easily live lock.  From Ben
    Greear.

 3) Openvswitch cannot report vport configuration changes reliably
    because it didn't preallocate the netlink notification message
    before changing state.  From Jesse Gross.

 4) The effective UID/GID SCM credentials fix, from Linus.

 5) When a user explicitly asks for wireless authentication, cfg80211
    isn't told about the AP detachment leaving inconsistent state.  Fix
    from Johannes Berg.

 6) Fix self-MAC checks in batman-adv on multi-mesh nodes, from Antonio
    Quartulli.

 7) Revert build_skb() change sin IGB driver, can result in memory
    corruption.  From Alexander Duyck.

 8) Fix setting VLANs on virtual functions in IXGBE, from Greg Rose.

 9) Fix TSO races in qlcnic driver, from Sritej Velaga.

10) In bnx2x the kernel driver and UNDI firmware can try to program the
    chip at the same time, resulting in corruption.  Add proper
    synchronization.  From Dmitry Kravkov.

11) Fix corruption of status block in firmware ram in bxn2x, from Ariel
    Elior.

12) Fix load balancing hash regression of bonding driver in forwarding
    configurations, from Eric Dumazet.

13) Fix TS ECR regression in TCP by calling tcp_replace_ts_recent() in
    all the right spots, from Eric Dumazet.

14) Fix several bonding bugs having to do with address manintainence,
    including not removing address when configuration operations
    encounter errors, missed locking on the address lists, missing
    refcounting on VLAN objects, etc.  All from Nikolay Aleksandrov.

15) Add workarounds for firmware bugs in LTE qmi_wwan devices, wherein
    the devices fail to add a proper ethernet header while on LTE
    networks but otherwise properly do so on 2G and 3G ones.  From Bjørn
    Mork.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (38 commits)
  net: fix incorrect credentials passing
  net: rate-limit warn-bad-offload splats.
  net: ax88796: avoid 64 bit arithmetic
  qlge: Update version to 1.00.00.32.
  qlge: Fix ethtool autoneg advertising.
  qlge: Fix receive path to drop error frames
  net: qmi_wwan: prevent duplicate mac address on link (firmware bug workaround)
  net: qmi_wwan: fixup destination address (firmware bug workaround)
  net: qmi_wwan: fixup missing ethernet header (firmware bug workaround)
  bonding: in bond_mc_swap() bond's mc addr list is walked without lock
  bonding: disable netpoll on enslave failure
  bonding: primary_slave & curr_active_slave are not cleaned on enslave failure
  bonding: vlans don't get deleted on enslave failure
  bonding: mc addresses don't get deleted on enslave failure
  pkt_sched: fix error return code in fw_change_attrs()
  irda: small read past the end of array in debug code
  tcp: call tcp_replace_ts_recent() from tcp_ack()
  netfilter: xt_rpfilter: skip locally generated broadcast/multicast, too
  netfilter: ipset: bitmap:ip,mac: fix listing with timeout
  bonding: fix l23 and l34 load balancing in forwarding path
  ...

Commit 257b5358 ("scm: Capture the full credentials of the scm
sender") changed the credentials passing code to pass in the effective
uid/gid instead of the real uid/gid.

Obviously this doesn't matter most of the time (since normally they are
the same), but it results in differences for suid binaries when the wrong
uid/gid ends up being used.

This just undoes that (presumably unintentional) part of the commit.
Reported-by: Andy Lutomirski <luto@amacapital.net>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Matt Fleming (1):
      x86, efivars: firmware bug workarounds should be in platform
      code

Matthew Garrett (3):
      Move utf16 functions to kernel core and rename
      efi: Pass boot services variable info to runtime code
      efi: Distinguish between "remaining space" and actually used
      space

Richard Weinberger (2):
      x86,efi: Check max_size only if it is non-zero.
      x86,efi: Implement efi_no_storage_paranoia parameter

Sergey Vlasov (2):
      x86/Kconfig: Make EFI select UCS2_STRING
      efi: Export efi_query_variable_store() for efivars.ko
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

For each CPU vendor that implements CPU microcode patching, there will
be a minimum family for which this is implemented.  Verify this
minimum level of support.

This can be done in the dispatch function or early in the application
functions.  Doing the latter turned out to be somewhat awkward because
of the ineviable split between the BSP and the AP paths, and rather
than pushing deep into the application functions, do this in
the dispatch function.
Reported-by: "Bryan O'Donoghue" <bryan.odonoghue.lkml@nexus-software.ie>
Suggested-by: Borislav Petkov <bp@alien8.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1366392183-4149-1-git-send-email-bryan.odonoghue.lkml@nexus-software.ie

If one does do something unfortunate and allow a
bad offload bug into the kernel, this the
skb_warn_bad_offload can effectively live-lock the
system, filling the logs with the same error over
and over.

Add rate limitation to this so that box remains otherwise
functional in this case.
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When building ax88796 on an ARM platform with 64-bit resource_size_t,
we currently get

drivers/net/ethernet/8390/ax88796.c:875: undefined reference to `__aeabi_uldivmod'

because we do a division on the length of the MMIO resource.
Since we know that this resource is very short, using an
"unsigned long" instead of "resource_size_t" is entirely
sufficient, and avoids this link-time error.

Cc: Ben Dooks <ben-linux@fluff.org>
Cc: netdev@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Jitendra Kalsaria <jitendra.kalsaria@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Autoneg is supported on specific port types only. Fix the driver to advertise
autoneg based on the port type.
Signed-off-by: Jitendra Kalsaria <jitendra.kalsaria@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

o Fix the driver to drop error frames in the receive path
o Update error counter which was not getting incremented
Signed-off-by: Sritej Velaga <sritej.velaga@qlogic.com>
Signed-off-by: Jitendra Kalsaria <jitendra.kalsaria@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Bjørn Mork says:

====================
This series adds workarounds for 3 different firmware bugs, each
preventing the affected devices from working at all. I therefore
humbly request that these fixes go to stable-3.8 (if still
maintained) and 3.9 (either via net if still possible, or via
stable if not).

All 3 workarounds are applied to all devices supported by the driver.
Adding quirks for specific devices was considered as an alternative,
but was rejected because we have too little information about the
exact distribution of the buggy firmwares. All we know is that the
same bug shows up in devices from at least 3 different, and presumably
independent, vendors.

The workarounds have instead been designed to automatically apply
when necessary, and to have as little impact as possible on unaffected
devices.  The series has been tested on a number of devices both with
and without these bugs.

The series should apply cleanly to net/master, net-next/master and
stable/linux-3.8.y
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

We normally trust and use the CDC functional descriptors provided by a
number of devices.  But some of these will erroneously list the address
reserved for the device end of the link.  Attempting to use this on
both the device and host side will naturally not work.

Work around this bug by ignoring the functional descriptor and assign a
random address instead in this case.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>

Received packets are sometimes addressed to 00:a0:c6:00:00:00
instead of the address the device firmware should have learned
from the host:

321.224126 77.16.85.204 -> 148.122.171.134 ICMP 98 Echo (ping) request  id=0x4025, seq=64/16384, ttl=64

0000  82 c0 82 c9 f1 67 82 c0 82 c9 f1 67 08 00 45 00   .....g.....g..E.
0010  00 54 00 00 40 00 40 01 57 cc 4d 10 55 cc 94 7a   .T..@.@.W.M.U..z
0020  ab 86 08 00 62 fc 40 25 00 40 b2 bc 6e 51 00 00   ....b.@%.@..nQ..
0030  00 00 6b bd 09 00 00 00 00 00 10 11 12 13 14 15   ..k.............
0040  16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25   .......... !"#$%
0050  26 27 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35   &'()*+,-./012345
0060  36 37                                             67

321.240607 148.122.171.134 -> 77.16.85.204 ICMP 98 Echo (ping) reply    id=0x4025, seq=64/16384, ttl=55

0000  00 a0 c6 00 00 00 02 50 f3 00 00 00 08 00 45 00   .......P......E.
0010  00 54 00 56 00 00 37 01 a0 76 94 7a ab 86 4d 10   .T.V..7..v.z..M.
0020  55 cc 00 00 6a fc 40 25 00 40 b2 bc 6e 51 00 00   U...j.@%.@..nQ..
0030  00 00 6b bd 09 00 00 00 00 00 10 11 12 13 14 15   ..k.............
0040  16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25   .......... !"#$%
0050  26 27 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35   &'()*+,-./012345
0060  36 37                                             67

The bogus address is always the same, and matches the address
suggested by many devices as a default address.  It is likely a
hardcoded firmware default.

The circumstances where this bug has been observed indicates that
the trigger is related to timing or some other factor the host
cannot control. Repeating the exact same configuration sequence
that caused it to trigger once, will not necessarily cause it to
trigger the next time. Reproducing the bug is therefore difficult.
This opens up a possibility that the bug is more common than we can
confirm, because affected devices often will work properly again
after a reset.  A procedure most users are likely to try out before
reporting a bug.

Unconditionally rewriting the destination address if the first digit
of the received packet is 0, is considered an acceptable compromise
since we already have to inspect this digit.  The simplification will
cause unnecessary rewrites if the real address starts with 0, but this
is still better than adding additional tests for this particular case.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>