We'll need that in the PCIe driver soon as we'll read it straight off the
CQ.

Signed-off-by: Christoph Hellwig <hch@lst.de>

AER handling expects a successful return from slot_reset means the
driver made the device functional again. The nvme driver had been using
an asynchronous reset to recover the device, so the device
may still be initializing after control is returned to the
AER handler. This creates problems for subsequent event handling,
causing the initializion to fail.

This patch fixes that by syncing the controller reset before returning
to the AER driver, and reporting the true state of the reset.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=199657


Reported-by: Alex Gagniuc <mr.nuke.me@gmail.com>
Cc: Sinan Kaya <okaya@codeaurora.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org
Tested-by: Alex Gagniuc <mr.nuke.me@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>

It is possible the driver's remove may have freed the controller if
the remove callback is invoked prior to the async_schedule starting
the reset_work. This patch fixes that by holding a reference on the
controller.

Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>

Currently nvme reconfigures discard for every disk revalidation. This
is problematic because any O_WRONLY or O_RDWR open will trigger a
partition scan through udev/systemd, and we will reconfigure discard.
This blows away any user settings, like discard_max_bytes.

Only re-configure the user settable settings if we need to.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
[removed redundant queue flag setting]
Signed-off-by: Keith Busch <keith.busch@intel.com>

This patch schedules the initial controller reset in an async_domain
so that it can be synchronized from wait_for_device_probe(). This way
the kernel waits for the initial nvme controller scan to complete for
all devices before proceeding with the boot sequence, which may have
nvme dependencies.

Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Tested-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>

Add a new lightnvm quirk to identify CNEX’s Granby controller.

Signed-off-by: Wei Xu <wxu@cnexlabs.com>
Reviewed-by: Javier González <javier@cnexlabs.com>
Reviewed-by: Matias Bjørling <mb@lightnvm.io>
Signed-off-by: Keith Busch <keith.busch@intel.com>

Add Seagate Nytro Flash Storage nvme drive to quirk list for
NVME_QUIRK_DELAY_BEFORE_CHK_RDY, which solves a bug where the drive is
probed on hot-add before the firmare is ready, I/O errors are generated
while reading sector 0, and linux is "unable to read partition table".

Signed-off-by: Micah Parrish <micah.parrish@hpe.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>

Keith reported that command submission and command completion
tracepoints have the order of the cmdid and qid fields swapped.

While it isn't easily possible to change the command submission
tracepoint, as there is a regression test parsing it in blktests we
can swap the command completion tracepoint to have the fields aligned.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reported-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Keith Busch <keith.busch@intel.com>

Provide a descriptive error in case an lport to rport association
isn't found when creating the FC-NVME controller.

Currently it's very hard to debug the reason for a failed connect
attempt without a look at the source.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>

Pull fsnotify fix from Jan Kara:
 "A fix of a fsnotify race causing panics / softlockups"

* tag 'for_v4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fsnotify: Fix fsnotify_mark_connector race

Pull SCSI fixes from James Bottomley:
 "Eight bug fixes, one spelling update and one tracepoint addition.

  The most serious is probably the mptsas write same fix because it
  means anyone using these controllers sees errors when modern
  filesystems try to issue discards"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: target: fix crash with iscsi target and dvd
  scsi: sd_zbc: Avoid that resetting a zone fails sporadically
  scsi: sd: Defer spinning up drive while SANITIZE is in progress
  scsi: megaraid_sas: Do not log an error if FW successfully initializes.
  scsi: ufs: add trace event for ufs upiu
  scsi: core: remove reference to scsi_show_extd_sense()
  scsi: mptsas: Disable WRITE SAME
  scsi: fnic: fix spelling mistake in fnic stats "Abord" -> "Abort"
  scsi: scsi_debug: IMMED related delay adjustments
  scsi: iscsi: respond to netlink with unicast when appropriate

Pull block updates from Jens Axboe:
 "I ended up sitting on this about a week longer than I wanted to, since
  we were hashing out details with a timeout change. I've now killed
  that patch, so we can flush the existing queue in due time.

  This contains:

   - Fix for an old regression, where entering the queue can be
     disturbed by a signal to the process. This can cause spurious EIO.
     Fix from Alan Jenkins.

   - cdrom information leak fix from Dan.

   - Trivial helper for testing queue FUA from Dave Chinner, part of his
     O_DIRECT FUA series.

   - Series of swim fixes from Finn that actually makes it work again.

   - Loop O_DIRECT corruption fix, which caused data corruption in
     production for us. From me.

   - BFQ crash fix from me.

   - bcache maintainer update. Michael no longer has the time to do it,
     Coly has stepped up to serve as the new maintainer.

   - blkcg locking fixes from Jiang Biao.

   - Revert of a change from this merge window from Ming, that causes an
     issue on some hardware.

   - Minor clarification doc addition from Linus Walleij"

* tag 'for-linus-20180425' of git://git.kernel.dk/linux-block: (22 commits)
  Revert "blk-mq: remove code for dealing with remapping queue"
  block: mq: Add some minor doc for core structs
  bcache: mark Coly Li as bcache maintainer
  MAINTAINERS: Remove me as maintainer of bcache
  blkcg: init root blkcg_gq under lock
  blkcg: small fix on comment in blkcg_init_queue
  blkcg: don't hold blkcg lock when deactivating policy
  block: add blk_queue_fua() helper function
  cdrom: information leak in cdrom_ioctl_media_changed()
  bfq-iosched: ensure to clear bic/bfqq pointers when preparing request
  blk-mq: start request gstate with gen 1
  block/swim: Select appropriate drive on device open
  block/swim: Fix IO error at end of medium
  block/swim: Check drive type
  block/swim: Rename macros to avoid inconsistent inverted logic
  block/swim: Don't log an error message for an invalid ioctl
  block/swim: Remove extra put_disk() call from error path
  block/swim: Fix array bounds check
  m68k/mac: Don't remap SWIM MMIO region
  loop: handle short DIO reads
  ...

Merge tag 'riscv-for-linus-4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux

Pull RISC-V fixes from Palmer Dabbelt:
 "This contains three small fixes related to the RISC-V port that I'd
  like to target for 4.17-rc3:

   - a Kconfig cleanup to select DMA_DIRECT_OPS instead of redefining it
     in arch/riscv

   - the removal of asm/handle_irq.h, which doesn't exist, from our arch
     header list

   - the addition of "-no-pie" the link rules for our VDSO-related
     files, which fixes the build on systems where PIE is enabled by
     default"

* tag 'riscv-for-linus-4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux:
  RISC-V: build vdso-dummy.o with -no-pie
  riscv: there is no <asm/handle_irq.h>
  riscv: select DMA_DIRECT_OPS instead of redefining it

Pull dma-mapping fixes from Christoph Hellwig:
 "A few small dma-mapping fixes for Linux 4.17-rc3:

   - don't loop to try GFP_DMA allocations if ZONE_DMA is not actually
     enabled (regression in 4.16)

   - don't try to do virt_to_page before we know we actuall have a valid
     page in dma_common_mmap

   - a comment fixup related to the above fix"

* tag 'dma-mapping-4.17-3' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: postpone cpu addr translation on mmap
  dma-coherent: clarify dma_mmap_from_dev_coherent documentation
  dma-direct: don't retry allocation for no-op GFP_DMA

This reverts commit 37c7c6c7.

Turns out some drivers(most are FC drivers) may not use managed
IRQ affinity, and has their customized .map_queues meantime, so
still keep this code for avoiding regression.

Reported-by: Laurence Oberman <loberman@redhat.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Tested-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Cc: Ewan Milne <emilne@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

As it came up in discussion on the mailing list that the semantic
meaning of 'blk_mq_ctx' and 'blk_mq_hw_ctx' isn't completely
obvious to everyone, let's add some minimal kerneldoc for a
starter.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Since Michael had to step back, Coly has agreed to be the new
maintainer. Mark him as such.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

Too much to do with other projects.  I've enjoyed working with everyone
here, and hope to occasionally contribute on bcache.

Signed-off-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull userns bug fix from Eric Biederman:
 "Just a small fix to properly set the return code on error"

* 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  commoncap: Handle memory allocation failure.

Pull networking fixes from David Miller:

 1) Fix rtnl deadlock in ipvs, from Julian Anastasov.

 2) s390 qeth fixes from Julian Wiedmann (control IO completion stalls,
    bad MAC address update sequence, request side races on command IO
    timeouts).

 3) Handle seq_file overflow properly in l2tp, from Guillaume Nault.

 4) Fix VLAN priority mappings in cpsw driver, from Ivan Khoronzhuk.

 5) Packet scheduler ife action fixes (malformed TLV lengths, etc.) from
    Alexander Aring.

 6) Fix out of bounds access in tcp md5 option parser, from Jann Horn.

 7) Missing netlink attribute policies in rtm_ipv6_policy table, from
    Eric Dumazet.

 8) Missing socket address length checks in l2tp and pppoe connect, from
    Guillaume Nault.

 9) Fix netconsole over team and bonding, from Xin Long.

10) Fix race with AF_PACKET socket state bitfields, from Willem de
    Bruijn.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (51 commits)
  ice: Fix insufficient memory issue in ice_aq_manage_mac_read
  sfc: ARFS filter IDs
  net: ethtool: Add missing kernel doc for FEC parameters
  packet: fix bitfield update race
  ice: Do not check INTEVENT bit for OICR interrupts
  ice: Fix incorrect comment for action type
  ice: Fix initialization for num_nodes_added
  igb: Fix the transmission mode of queue 0 for Qav mode
  ixgbevf: ensure xdp_ring resources are free'd on error exit
  team: fix netconsole setup over team
  amd-xgbe: Only use the SFP supported transceiver signals
  amd-xgbe: Improve KR auto-negotiation and training
  amd-xgbe: Add pre/post auto-negotiation phy hooks
  pppoe: check sockaddr length in pppoe_connect()
  l2tp: check sockaddr length in pppol2tp_connect()
  net: phy: marvell: clear wol event before setting it
  ipv6: add RTA_TABLE and RTA_PREFSRC to rtm_ipv6_policy
  bonding: do not set slave_dev npinfo before slave_enable_netpoll in bond_enslave
  tcp: don't read out-of-bounds opsize
  ibmvnic: Clean actual number of RX or TX pools
  ...

Jeff Kirsher says:

====================
Intel Wired LAN Driver Updates 2018-04-24

This series contains fixes to ixgbevf, igb and ice drivers.

Colin Ian King fixes the return value on error for the new XDP support
that went into ixgbevf for 4.17.

Vinicius provides a fix for queue 0 for igb, which was not receiving all
the credits it needed when QAV mode was enabled.

Anirudh provides several fixes for the new ice driver, starting with
properly initializing num_nodes_added to zero.  Fixed up a code comment
to better reflect what is really going on in the code.  Fixed how to
detect if an OICR interrupt has occurred to a more reliable method.

Md Fahad fixes the ice driver to allocate the right amount of memory
when reading and storing the devices MAC addresses.  The device can have
up to 2 MAC addresses (LAN and WoL), while WoL is currently not
supported, we need to ensure it can be properly handled when support is
added.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

For the MAC read operation, the device can return up to two (LAN and WoL)
MAC addresses. Without access to adequate memory, the device will return
an error. Fixed this by allocating the right amount of memory. Also, logic
to detect and copy the LAN MAC address into the port_info structure has
been added. Note that the WoL MAC address is ignored currently as the WoL
feature isn't supported yet.

Fixes: dc49c772 ("ice: Get MAC/PHY/link info and scheduler topology")
Signed-off-by: Md Fahad Iqbal Polash <md.fahad.iqbal.polash@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Debian toolcahin defaults to PIE, and I guess that will also be the case
of most distributions. This causes the following build failure:

  AS      arch/riscv/kernel/vdso/getcpu.o
  AS      arch/riscv/kernel/vdso/flush_icache.o
  VDSOLD  arch/riscv/kernel/vdso/vdso.so.dbg
  OBJCOPY arch/riscv/kernel/vdso/vdso.so
  AS      arch/riscv/kernel/vdso/vdso.o
  VDSOLD  arch/riscv/kernel/vdso/vdso-dummy.o
  LD      arch/riscv/kernel/vdso/vdso-syms.o
riscv64-linux-gnu-ld: attempted static link of dynamic object `arch/riscv/kernel/vdso/vdso-dummy.o'
make[2]: *** [arch/riscv/kernel/vdso/Makefile:43: arch/riscv/kernel/vdso/vdso-syms.o] Error 1
make[1]: *** [scripts/Makefile.build:575: arch/riscv/kernel/vdso] Error 2
make: *** [Makefile:1018: arch/riscv/kernel] Error 2

While the root Makefile correctly passes "-fno-PIE" to build individual
object files, the RISC-V kernel also builds vdso-dummy.o as an
executable, which is therefore linked as PIE. Fix that by updating this
specific link rule to also include "-no-pie".

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

So don't list it as generic-y.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

DMA_DIRECT_OPS is defined in lib/Kconfig, so don't duplicate it in
arch/riscv/Kconfig.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

Associate an arbitrary ID with each ARFS filter, allowing to properly query
 for expiry.  The association is maintained in a hash table, which is
 protected by a spinlock.

v3: fix build warnings when CONFIG_RFS_ACCEL is disabled (thanks lkp-robot).
v2: fixed uninitialised variable (thanks davem and lkp-robot).

Fixes: 3af0f342 ("sfc: replace asynchronous filter operations")
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

While adding support for ethtool::get_fecparam and set_fecparam, kernel
doc for these functions was missed, add those.

Fixes: 1a5f3da2 ("net: ethtool: add support for forward error correction modes")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Updates to the bitfields in struct packet_sock are not atomic.
Serialize these read-modify-write cycles.

Move po->running into a separate variable. Its writes are protected by
po->bind_lock (except for one startup case at packet_create). Also
replace a textual precondition warning with lockdep annotation.

All others are set only in packet_setsockopt. Serialize these
updates by holding the socket lock. Analogous to other field updates,
also hold the lock when testing whether a ring is active (pg_vec).

Fixes: 8dc41944 ("[PACKET]: Add optional checksum computation for recvmsg")
Reported-by: DaeRyong Jeong <threeearcat@gmail.com>
Reported-by: Byoungyoung Lee <byoungyoung@purdue.edu>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

According to the hardware spec, checking the INTEVENT bit isn't a
reliable way to detect if an OICR interrupt has occurred. This is
because this bit can be cleared by the hardware/firmware before the
interrupt service routine has run. So instead, just check for OICR
events every time.

Fixes: 940b61af ("ice: Initialize PF and setup miscellaneous interrupt")
Signed-off-by: Ben Shelton <benjamin.h.shelton@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Action type 5 defines large action generic values. Fix comment to
reflect that better.

Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

ice_sched_add_nodes_to_layer is used recursively, and so we start
with num_nodes_added being 0. This way, in case of an error or if
num_nodes is NULL, the function just returns 0 to indicate that no
nodes were added.

Fixes: 5513b920 ("ice: Update Tx scheduler tree for VSI multi-Tx queue support")
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

When Qav mode is enabled, queue 0 should be kept on Stream Reservation
mode. From the i210 datasheet, section 8.12.19:

"Note: Queue0 QueueMode must be set to 1b when TransmitMode is set to
Qav." ("QueueMode 1b" represents the Stream Reservation mode)

The solution is to give queue 0 the all the credits it might need, so
it has priority over queue 1.

A situation where this can happen is when cbs is "installed" only on
queue 1, leaving queue 0 alone. For example:

$ tc qdisc replace dev enp2s0 handle 100: parent root mqprio num_tc 3 \
     	   map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 queues 1@0 1@1 2@2 hw 0

$ tc qdisc replace dev enp2s0 parent 100:2 cbs locredit -1470 \
     	   hicredit 30 sendslope -980000 idleslope 20000 offload 1

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

The current error handling for failed resource setup for xdp_ring
data is a break out of the loop and returning 0 indicated everything
was OK, when in fact it is not.  Fix this by exiting via the
error exit label err_setup_tx that will clean up the resources
correctly and return and error status.

Detected by CoverityScan, CID#1466879 ("Logically dead code")

Fixes: 21092e9c ("ixgbevf: Add support for XDP_TX action")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

The same fix in Commit dbe17307 ("bridge: fix netconsole
setup over bridge") is also needed for team driver.

While at it, remove the unnecessary parameter *team from
team_port_enable_netpoll().

v1->v2:
  - fix it in a better way, as does bridge.

Fixes: 0fb52a27 ("team: cleanup netpoll clode")
Reported-by: João Avelino Bellomo Filho <jbellomo@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

aTom Lendacky says:

====================
amd-xgbe: AMD XGBE driver fixes 2018-04-23

This patch series addresses some issues in the AMD XGBE driver.

The following fixes are included in this driver update series:

- Improve KR auto-negotiation and training (2 patches)
  - Add pre and post auto-negotiation hooks
  - Use the pre and post auto-negotiation hooks to disable CDR tracking
    during auto-negotiation page exchange in KR mode
- Check for SFP tranceiver signal support and only use the signal if the
  SFP indicates that it is supported

This patch series is based on net.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

The SFP eeprom indicates the transceiver signals (Rx LOS, Tx Fault, etc.)
that it supports.  Update the driver to include checking the eeprom data
when deciding whether to use a transceiver signal.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Update xgbe-phy-v2.c to make use of the auto-negotiation (AN) phy hooks
to improve the ability to successfully complete Clause 73 AN when running
at 10gbps.  Hardware can sometimes have issues with CDR lock when the
AN DME page exchange is being performed.

The AN and KR training hooks are used as follows:
- The pre AN hook is used to disable CDR tracking in the PHY so that the
  DME page exchange can be successfully and consistently completed.
- The post KR training hook is used to re-enable the CDR tracking so that
  KR training can successfully complete.
- The post AN hook is used to check for an unsuccessful AN which will
  increase a CDR tracking enablement delay (up to a maximum value).

Add two debugfs entries to allow control over use of the CDR tracking
workaround.  The debugfs entries allow the CDR tracking workaround to
be disabled and determine whether to re-enable CDR tracking before or
after link training has been initiated.

Also, with these changes the receiver reset cycle that is performed during
the link status check can be performed less often.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add hooks to the driver auto-negotiation (AN) flow to allow the different
phy implementations to perform any steps necessary to improve AN.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We must validate sockaddr_len, otherwise userspace can pass fewer data
than we expect and we end up accessing invalid data.

Fixes: 224cf5ad ("ppp: Move the PPP drivers")
Reported-by:  <syzbot+4f03bdf92fdf9ef5ddab@syzkaller.appspotmail.com>
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

Check sockaddr_len before dereferencing sp->sa_protocol, to ensure that
it actually points to valid data.

Fixes: fd558d18 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Reported-by:  <syzbot+a70ac890b23b1bf29f5c@syzkaller.appspotmail.com>
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>