During mmaping of frame-buffer pages to user-space
fb_protect() is called to set proper page settings.

In case of ARC we need to mark pages that are mmaped to
user as uncached because of 2 reasons:
 * Huge amount of data if passing through data cache will
   thrash cache a lot making cache almost useless for other
   less traffic hungry processes.
 * Data written by user in FB will be immediately available for
   hardware (such as PGU etc) without requirements to flush data
   cache regularly.
Signed-off-by: NAlexey Brodkin <abrodkin@synopsys.com>
Cc: linux-snps-arc@lists.infradead.org
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

Commit 5f8fc432 ("PCI: Include pci/pcie/Kconfig directly from
pci/Kconfig") in linux-next changed drivers/pci/Kconfig to include
drivers/pci/pcie/Kconfig itself, so that architectures do not need
to source both files themselves. ARC just recently gained PCI support
through commit 6b3fb77998dd ("ARC: Add PCI support"), but this change
was based on the old behaviour of the Kconfig files. This makes
Kconfig now spit out the following warnings:

drivers/pci/pcie/Kconfig:61:warning: choice value used outside its choice group
drivers/pci/pcie/Kconfig:67:warning: choice value used outside its choice group
drivers/pci/pcie/Kconfig:74:warning: choice value used outside its choice group

This change updates the Kconfig file for ARC, dropping the now
unnecessary 'source' statement, which makes the warning disappear.
Signed-off-by: NAndreas Ziegler <andreas.ziegler@fau.de>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

Pull perf fixes from Ingo Molnar:
 "Misc kernel side fixes:

   - fix event leak
   - fix AMD PMU driver bug
   - fix core event handling bug
   - fix build bug on certain randconfigs

  Plus misc tooling fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/amd/ibs: Fix pmu::stop() nesting
  perf/core: Don't leak event in the syscall error path
  perf/core: Fix time tracking bug with multiplexing
  perf jit: genelf makes assumptions about endian
  perf hists: Fix determination of a callchain node's childlessness
  perf tools: Add missing initialization of perf_sample.cpumode in synthesized samples
  perf tools: Fix build break on powerpc
  perf/x86: Move events_sysfs_show() outside CPU_SUP_INTEL
  perf bench: Fix detached tarball building due to missing 'perf bench memcpy' headers
  perf tests: Fix tarpkg build test error output redirection

Pull core kernel fixes from Ingo Molnar:
 "This contains the nohz/atomic cleanup/fix for the fetch_or() ugliness
  you noted during the original nohz pull request, plus there's also
  misc fixes:

   - fix liblockdep build bug
   - fix uapi header build bug
   - print more lockdep hash collision info to help debug recent reports
     of hash collisions
   - update MAINTAINERS email address"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Update my email address
  locking/lockdep: Print chain_key collision information
  uapi/linux/stddef.h: Provide __always_inline to userspace headers
  tools/lib/lockdep: Fix unsupported 'basename -s' in run_tests.sh
  locking/atomic, sched: Unexport fetch_or()
  timers/nohz: Convert tick dependency mask to atomic_t
  locking/atomic: Introduce atomic_fetch_or()

Commit 840f5b05 ("media: au0828 disable tuner to demod link in
au0828_media_device_register()") removed all uses of the 'dtv_demod',
but left the variable itself around.

Remove it.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull x86 fixes from Thomas Gleixner:
 "This lot contains:

   - Some fixups for the fallout of the topology consolidation which
     unearthed AMD/Intel inconsistencies
   - Documentation for the x86 topology management
   - Support for AMD advanced power management bits
   - Two simple cleanups removing duplicated code"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Add advanced power management bits
  x86/thread_info: Merge two !__ASSEMBLY__ sections
  x86/cpufreq: Remove duplicated TDP MSR macro definitions
  x86/Documentation: Start documenting x86 topology
  x86/cpu: Get rid of compute_unit_id
  perf/x86/amd: Cleanup Fam10h NB event constraints
  x86/topology: Fix AMD core count

Pull remoteproc fix from Bjorn Andersson:
 "Fix incorrect error check in the ST remoteproc driver and advertise
  the newly created linux-remoteproc mailing list"

* tag 'rproc-v4.6-rc1' of git://github.com/andersson/remoteproc:
  MAINTAINERS: Add mailing list for remote processor subsystems
  remoteproc: st: fix check of syscon_regmap_lookup_by_phandle() return value

Pull SCSI target fixes from Nicholas Bellinger:
 "This includes fixes from HCH for -rc1 configfs default_groups
  conversion changes that ended up breaking some iscsi-target
  default_groups, along with Sagi's ib_drain_qp() conversion for
  iser-target to use the common caller now available to RDMA kernel
  consumers in v4.6+ code"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  target: add a new add_wwn_groups fabrics method
  target: initialize the nacl base CIT begfore init_nodeacl
  target: remove ->fabric_cleanup_nodeacl
  iser-target: Use ib_drain_qp

Commit d4edcf0d ("mm/gup: Switch all callers of get_user_pages() to
not pass tsk/mm") switched get_user_pages() callers to the simpler model
where they no longer pass in the thread and mm pointer.  But since then
we've merged changes to a few drivers that re-introduce use of the old
interface.  Let's fix them up.

They continued to work fine (thanks to the truly disgusting macros
introduced in commit cde70140: "mm/gup: Overload get_user_pages()
functions"), but cause unnecessary build noise.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull configfs fix from Christoph Hellwig:
 "A trivial fix to the recently introduced binary attribute helper
  macros"

* tag 'configfs-for-linus-2' of git://git.infradead.org/users/hch/configfs:
  configfs: fix CONFIGFS_BIN_ATTR_[RW]O definitions

Pull networking fixes from David Miller:

 1) Missing device reference in IPSEC input path results in crashes
    during device unregistration.  From Subash Abhinov Kasiviswanathan.

 2) Per-queue ISR register writes not being done properly in macb
    driver, from Cyrille Pitchen.

 3) Stats accounting bugs in bcmgenet, from Patri Gynther.

 4) Lightweight tunnel's TTL and TOS were swapped in netlink dumps, from
    Quentin Armitage.

 5) SXGBE driver has off-by-one in probe error paths, from Rasmus
    Villemoes.

 6) Fix race in save/swap/delete options in netfilter ipset, from
    Vishwanath Pai.

 7) Ageing time of bridge not set properly when not operating over a
    switchdev device.  Fix from Haishuang Yan.

 8) Fix GRO regression wrt nested FOU/GUE based tunnels, from Alexander
    Duyck.

 9) IPV6 UDP code bumps wrong stats, from Eric Dumazet.

10) FEC driver should only access registers that actually exist on the
    given chipset, fix from Fabio Estevam.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (73 commits)
  net: mvneta: fix changing MTU when using per-cpu processing
  stmmac: fix MDIO settings
  Revert "stmmac: Fix 'eth0: No PHY found' regression"
  stmmac: fix TX normal DESC
  net: mvneta: use cache_line_size() to get cacheline size
  net: mvpp2: use cache_line_size() to get cacheline size
  net: mvpp2: fix maybe-uninitialized warning
  tun, bpf: fix suspicious RCU usage in tun_{attach, detach}_filter
  net: usb: cdc_ncm: adding Telit LE910 V2 mobile broadband card
  rtnl: fix msg size calculation in if_nlmsg_size()
  fec: Do not access unexisting register in Coldfire
  net: mvneta: replace MVNETA_CPU_D_CACHE_LINE_SIZE with L1_CACHE_BYTES
  net: mvpp2: replace MVPP2_CPU_D_CACHE_LINE_SIZE with L1_CACHE_BYTES
  net: dsa: mv88e6xxx: Clear the PDOWN bit on setup
  net: dsa: mv88e6xxx: Introduce _mv88e6xxx_phy_page_{read, write}
  bpf: make padding in bpf_tunnel_key explicit
  ipv6: udp: fix UDP_MIB_IGNOREDMULTI updates
  bnxt_en: Fix ethtool -a reporting.
  bnxt_en: Fix typo in bnxt_hwrm_set_pause_common().
  bnxt_en: Implement proper firmware message padding.
  ...

Pull clk fixes from Stephen Boyd:
 "A handful of const updates for reset ops and a couple fixes to the
  newly introduced IPQ4019 clock driver"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: qcom: ipq4019: add some fixed clocks for ddrppl and fepll
  clk: qcom: ipq4019: switch remaining defines to enums
  clk: qcom: Make reset_control_ops const
  clk: tegra: Make reset_control_ops const
  clk: sunxi: Make reset_control_ops const
  clk: atlas7: Make reset_control_ops const
  clk: rockchip: Make reset_control_ops const
  clk: mmp: Make reset_control_ops const
  clk: mediatek: Make reset_control_ops const

Pull power management and ACPI fix from Rafael J. Wysocki:
 "Just one fix for a nasty boot failure on some systems based on Intel
  Skylake that shipped with broken firmware where enabling
  hardware-coordinated P-states management (HWP) causes a faulty
  interrupt handler in SMM to be invoked and crash the system (Srinivas
  Pandruvada)"

* tag 'pm+acpi-4.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / processor: Request native thermal interrupt handling via _OSC

Merge fixes from Andrew Morton:
 "11 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  .mailmap: add Christophe Ricard
  Make CONFIG_FHANDLE default y
  mm/page_isolation.c: fix the function comments
  oom, oom_reaper: do not enqueue task if it is on the oom_reaper_list head
  mm/page_isolation: fix tracepoint to mirror check function behavior
  mm/rmap: batched invalidations should use existing api
  x86/mm: TLB_REMOTE_SEND_IPI should count pages
  mm: fix invalid node in alloc_migrate_target()
  include/linux/huge_mm.h: return NULL instead of false for pmd_trans_huge_lock()
  mm, kasan: fix compilation for CONFIG_SLAB
  MAINTAINERS: orangefs mailing list is subscribers-only

* acpi-processor:
  ACPI / processor: Request native thermal interrupt handling via _OSC

Pull btrfs fixes from Chris Mason:
 "This has a few fixes Dave Sterba had queued up.  These are all pretty
  small, but since they were tested I decided against waiting for more"

* 'for-linus-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: transaction_kthread() is not freezable
  btrfs: cleaner_kthread() doesn't need explicit freeze
  btrfs: do not write corrupted metadata blocks to disk
  btrfs: csum_tree_block: return proper errno value

Pull OrangeFS fixes from Martin Brandenburg:
 "Two bugfixes for OrangeFS.

  One is a reference counting bug and the other is a typo in client
  minimum version"

* tag 'for-linus' of git://github.com/martinbrandenburg/linux:
  orangefs: minimum userspace version is 2.9.3
  orangefs: don't put readdir slot twice

Pull arm64 fixes from Will Deacon:

 - fix oops when patching in alternative sequences on big-endian CPUs

 - reconcile asm/perf_event.h after merge window fallout with KVM ARM

 - defconfig updates

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: defconfig: updates for 4.6
  arm64: perf: Move PMU register related defines to asm/perf_event.h
  arm64: opcodes.h: Add arm big-endian config options before including arm header

Pull sound fixes from Takashi Iwai:
 "A collection of small fixes:

   - a fix in ALSA timer core to avoid possible BUG() trigger
   - a fix in ALSA timer core 32bit compat layer
   - a few HD-audio quirks for ASUS and HP machines
   - AMD HD-audio HDMI controller quirks
   - fixes of USB-audio double-free at some error paths
   - a fix for memory leak in DICE driver at hotunplug"

* tag 'sound-4.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: timer: Use mod_timer() for rearming the system timer
  ALSA: hda - fix front mic problem for a HP desktop
  ALSA: usb-audio: Fix double-free in error paths after snd_usb_add_audio_stream() call
  ALSA: hda: add AMD Polaris-10/11 AZ PCI IDs with proper driver caps
  ALSA: dice: fix memory leak when unplugging
  ALSA: hda - Apply fix for white noise on Asus N550JV, too
  ALSA: hda - Fix white noise on Asus N750JV headphone
  ALSA: hda - Asus N750JV external subwoofer fixup
  ALSA: timer: fix gparams ioctl compatibility for different architectures

Different computers had different settings in the mail client.  Some
contributions appear as Christophe Ricard, others as Christophe RICARD.
Signed-off-by: NChristophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Newer Fedora and OpenSUSE didn't boot with my standard configuration.
It took me some time to figure out why, in fact I had to write a script
to try different config options systematically.

The problem is that something (systemd) in dracut depends on
CONFIG_FHANDLE, which adds open by file handle syscalls.

While it is set in defconfigs it is very easy to miss when updating
older configs because it is not default y.

Make it default y and also depend on EXPERT, as dracut use is likely
widespread.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Cc: Richard Weinberger <richard.weinberger@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit fea85cff ("mm/page_isolation.c: return last tested pfn rather
than failure indicator") changed the meaning of the return value.  Let's
change the function comments as well.
Signed-off-by: NNeil Zhang <neilzhang1123@hotmail.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit bb29902a ("oom, oom_reaper: protect oom_reaper_list using
simpler way") has simplified the check for tasks already enqueued for
the oom reaper by checking tsk->oom_reaper_list != NULL.  This check is
not sufficient because the tsk might be the head of the queue without
any other tasks queued and then we would simply lockup looping on the
same task.  Fix the condition by checking for the head as well.

Fixes: bb29902a ("oom, oom_reaper: protect oom_reaper_list using simpler way")
Signed-off-by: NMichal Hocko <mhocko@suse.com>
Acked-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Page isolation has not failed if the fin pfn extends beyond the end pfn
and test_pages_isolated checks this correctly.  Fix the tracepoint to
report the same result as the actual check function.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The recently introduced batched invalidations mechanism uses its own
mechanism for shootdown.  However, it does wrong accounting of
interrupts (e.g., inc_irq_stat is called for local invalidations),
trace-points (e.g., TLB_REMOTE_SHOOTDOWN for local invalidations) and
may break some platforms as it bypasses the invalidation mechanisms of
Xen and SGI UV.

This patch reuses the existing TLB flushing mechnaisms instead.  We use
NULL as mm to indicate a global invalidation is required.

Fixes 72b252ae ("mm: send one IPI per CPU to TLB flush all entries after unmapping pages")
Signed-off-by: NNadav Amit <namit@vmware.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

TLB_REMOTE_SEND_IPI was recently introduced, but it counts bytes instead
of pages.  In addition, it does not report correctly the case in which
flush_tlb_page flushes a page.  Fix it to be consistent with other TLB
counters.

Fixes: 5b74283a ("x86, mm: trace when an IPI is about to be sent")
Signed-off-by: NNadav Amit <namit@vmware.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It is incorrect to use next_node to find a target node, it will return
MAX_NUMNODES or invalid node.  This will lead to crash in buddy system
allocation.

Fixes: c8721bbb ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Signed-off-by: NXishi Qiu <qiuxishi@huawei.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Acked-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Laura Abbott" <lauraa@codeaurora.org>
Cc: Hui Zhu <zhuhui@xiaomi.com>
Cc: Wang Xiaoqiang <wangxq10@lzu.edu.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The return value of pmd_trans_huge_lock() is a pointer, not a boolean
value, so use NULL instead of false as the return value.
Signed-off-by: NChen Gang <gang.chen.5i5j@gmail.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add the missing argument to set_track().

Fixes: cd11016e ("mm, kasan: stackdepot implementation. Enable stackdepot for SLAB")
Signed-off-by: NAlexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Konstantin Serebryany <kcc@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

So update MAINTAINERS to say so.
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: Mike Marshall <hubcap@omnibond.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

After enabling per-cpu processing it appeared that under heavy load
changing MTU can result in blocking all port's interrupts and
transmitting data is not possible after the change.

This commit fixes above issue by disabling percpu interrupts for the
time, when TXQs and RXQs are reconfigured.
Signed-off-by: NMarcin Wojtas <mw@semihalf.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Giuseppe Cavallaro says:

====================
stmmac MDIO and normal descr fixes

This patch series is to fix the problems below and recently debugged
in this mailing list:

o to fix a problem for the HW where the normal descriptor
o to fix the mdio registration according to the different
  platform configurations

I am resending all the patches again: built on top of net.git repo.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Initially the phy_bus_name was added to manipulate the
driver name but it was recently just used to manage the
fixed-link and then to take some decision at run-time.
So the patch uses the is_pseudo_fixed_link and removes
the phy_bus_name variable not necessary anymore.

The driver can manage the mdio registration by using phy-handle,
dwmac-mdio and own parameter e.g. snps,phy-addr.
This patch takes care about all these possible configurations
and fixes the mdio registration in case of there is a real
transceiver or a switch (that needs to be managed by using
fixed-link).
Signed-off-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Reviewed-by: NAndreas Färber <afaerber@suse.de>
Tested-by: NFrank Schäfer <fschaefer.oss@googlemail.com>
Cc: Gabriel Fernandez <gabriel.fernandez@linaro.org>
Cc: Dinh Nguyen <dinh.linux@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Phil Reid <preid@electromag.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 88f8b1bb.
due to problems on GeekBox and Banana Pi M1 board when
connected to a real transceiver instead of a switch via
fixed-link.
Signed-off-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Gabriel Fernandez <gabriel.fernandez@linaro.org>
Cc: Andreas Färber <afaerber@suse.de>
Cc: Frank Schäfer <fschaefer.oss@googlemail.com>
Cc: Dinh Nguyen <dinh.linux@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixs a regression raised when test on chips that use
the normal descriptor layout. In fact, no len bits were set for
the TDES1 and no OWN bit inside the TDES0.
Signed-off-by: NGiuseppe CAVALLARO <peppe.cavallaro@st.com>
Tested-by: NAndreas Färber <afaerber@suse.de>
Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

L1_CACHE_BYTES may not be the real cacheline size, use cache_line_size
to determine the cacheline size in runtime.
Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
Suggested-by: NMarcin Wojtas <mw@semihalf.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

L1_CACHE_BYTES may not be the real cacheline size, use cache_line_size
to determine the cacheline size in runtime.
Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
Suggested-by: NMarcin Wojtas <mw@semihalf.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is to fix the following maybe-uninitialized warning:

drivers/net/ethernet/marvell/mvpp2.c:6007:18: warning: 'err' may be
used uninitialized in this function [-Wmaybe-uninitialized]
Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Sasha Levin reported a suspicious rcu_dereference_protected() warning
found while fuzzing with trinity that is similar to this one:

  [   52.765684] net/core/filter.c:2262 suspicious rcu_dereference_protected() usage!
  [   52.765688] other info that might help us debug this:
  [   52.765695] rcu_scheduler_active = 1, debug_locks = 1
  [   52.765701] 1 lock held by a.out/1525:
  [   52.765704]  #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff816a64b7>] rtnl_lock+0x17/0x20
  [   52.765721] stack backtrace:
  [   52.765728] CPU: 1 PID: 1525 Comm: a.out Not tainted 4.5.0+ #264
  [...]
  [   52.765768] Call Trace:
  [   52.765775]  [<ffffffff813e488d>] dump_stack+0x85/0xc8
  [   52.765784]  [<ffffffff810f2fa5>] lockdep_rcu_suspicious+0xd5/0x110
  [   52.765792]  [<ffffffff816afdc2>] sk_detach_filter+0x82/0x90
  [   52.765801]  [<ffffffffa0883425>] tun_detach_filter+0x35/0x90 [tun]
  [   52.765810]  [<ffffffffa0884ed4>] __tun_chr_ioctl+0x354/0x1130 [tun]
  [   52.765818]  [<ffffffff8136fed0>] ? selinux_file_ioctl+0x130/0x210
  [   52.765827]  [<ffffffffa0885ce3>] tun_chr_ioctl+0x13/0x20 [tun]
  [   52.765834]  [<ffffffff81260ea6>] do_vfs_ioctl+0x96/0x690
  [   52.765843]  [<ffffffff81364af3>] ? security_file_ioctl+0x43/0x60
  [   52.765850]  [<ffffffff81261519>] SyS_ioctl+0x79/0x90
  [   52.765858]  [<ffffffff81003ba2>] do_syscall_64+0x62/0x140
  [   52.765866]  [<ffffffff817d563f>] entry_SYSCALL64_slow_path+0x25/0x25

Same can be triggered with PROVE_RCU (+ PROVE_RCU_REPEATEDLY) enabled
from tun_attach_filter() when user space calls ioctl(tun_fd, TUN{ATTACH,
DETACH}FILTER, ...) for adding/removing a BPF filter on tap devices.

Since the fix in f91ff5b9 ("net: sk_{detach|attach}_filter() rcu
fixes") sk_attach_filter()/sk_detach_filter() now dereferences the
filter with rcu_dereference_protected(), checking whether socket lock
is held in control path.

Since its introduction in 99405162 ("tun: socket filter support"),
tap filters are managed under RTNL lock from __tun_chr_ioctl(). Thus the
sock_owned_by_user(sk) doesn't apply in this specific case and therefore
triggers the false positive.

Extend the BPF API with __sk_attach_filter()/__sk_detach_filter() pair
that is used by tap filters and pass in lockdep_rtnl_is_held() for the
rcu_dereference_protected() checks instead.
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>