Symptom: After vnicc/rx_bcast has been manually set to 0,
	bridge_* sysfs parameters can still be set or written.
Only occurs on HiperSockets, as OSA doesn't support changing rx_bcast.

Vnic characteristics and bridgeport settings are mutually exclusive.
rx_bcast defaults to 1, so manually setting it to 0 should disable
bridge_* parameters.

Instead it makes sense here to check the supported mask. If the card
does not support vnicc at all, bridge commands are always allowed.

Fixes: caa1f0b1 ("s390/qeth: add VNICC enable/disable support")
Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Symptom: Error message "Configuring the VNIC characteristics failed"
in dmesg whenever an OSA interface on z15 is set online.

The VNIC characteristics get re-programmed when setting a L2 device
online. This follows the selected 'wanted' characteristics - with the
exception that the INVISIBLE characteristic unconditionally gets
switched off.

For devices that don't support INVISIBLE (ie. OSA), the resulting
IO failure raises a noisy error message
("Configuring the VNIC characteristics failed").
For IQD, INVISIBLE is off by default anyways.

So don't unnecessarily special-case the INVISIBLE characteristic, and
thereby suppress the misleading error message on OSA devices.

Fixes: caa1f0b1 ("s390/qeth: add VNICC enable/disable support")
Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

qeth_l3_dev_hsuid_store() initially checks the card state, but doesn't
take the conf_mutex to ensure that the card stays in this state while
being reconfigured.

Rework the code to take this lock, and drop a redundant state check in a
helper function.

Fixes: b3332930 ("qeth: add support for af_iucv HiperSockets transport")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

qeth_l?_set_online() goes through a number of initialization steps, and
on any error uses qeth_l?_stop_card() to tear down the residual state.

The first initialization step is qeth_core_hardsetup_card(). When this
fails after having established a QDIO context on the device
(ie. somewhere after qeth_mpc_initialize()), qeth_l?_stop_card() doesn't
shut down this QDIO context again (since the card state hasn't
progressed from DOWN at this stage).

Even worse, we then call qdio_free() as final teardown step to free the
QDIO data structures - while some of them are still hooked into wider
QDIO infrastructure such as the IRQ list. This is inevitably followed by
use-after-frees and other nastyness.

Fix this by unconditionally calling qeth_qdio_clear_card() to shut down
the QDIO context, and also to halt/clear any pending activity on the
various IO channels.
Remove the naive attempt at handling the teardown in
qeth_mpc_initialize(), it clearly doesn't suffice and we're handling it
properly now in the wider teardown code.

Fixes: 4a71df50 ("qeth: new qeth device driver")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Hangbin Liu says:

====================
disable neigh update for tunnels during pmtu update

When we setup a pair of gretap, ping each other and create neighbour cache.
Then delete and recreate one side. We will never be able to ping6 to the new
created gretap.

The reason is when we ping6 remote via gretap, we will call like

gre_tap_xmit()
 - ip_tunnel_xmit()
   - tnl_update_pmtu()
     - skb_dst_update_pmtu()
       - ip6_rt_update_pmtu()
         - __ip6_rt_update_pmtu()
           - dst_confirm_neigh()
             - ip6_confirm_neigh()
               - __ipv6_confirm_neigh()
                 - n->confirmed = now

As the confirmed time updated, in neigh_timer_handler() the check for
NUD_DELAY confirm time will pass and the neigh state will back to
NUD_REACHABLE. So the old/wrong mac address will be used again.

If we do not update the confirmed time, the neigh state will go to
neigh->nud_state = NUD_PROBE; then go to NUD_FAILED and re-create the
neigh later, which is what IPv4 does.

We couldn't remove the ip6_confirm_neigh() directly as we still need it
for TCP flows. To fix it, we have to pass a bool parameter to
dst_ops.update_pmtu() and only disable neighbor update for tunnels.

v5: No code change, upate some commits description
v4: No code change, upate some commits description
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
    dst_ops.update_pmtu to control whether we should do neighbor confirm.
    Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

When do IPv6 tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end,
we should not call dst_confirm_neigh() as there is no two-way communication.

So disable the neigh confirm for vxlan and geneve pmtu update.

v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
    dst_ops.update_pmtu to control whether we should do neighbor confirm.
    Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.

Fixes: a93bf0ff ("vxlan: update skb dst pmtu on tx path")
Fixes: 52a589d5 ("geneve: update skb dst pmtu on tx path")
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Tested-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When do IPv6 tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end,
we should not call dst_confirm_neigh() as there is no two-way communication.

v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
    dst_ops.update_pmtu to control whether we should do neighbor confirm.
    Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When do IPv6 tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end,
we should not call dst_confirm_neigh() as there is no two-way communication.

Although vti and vti6 are immune to this problem because they are IFF_NOARP
interfaces, as Guillaume pointed. There is still no sense to confirm neighbour
here.

v5: Update commit description.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
    dst_ops.update_pmtu to control whether we should do neighbor confirm.
    Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When do tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end,
we should not call dst_confirm_neigh() as there is no two-way communication.

v5: No Change.
v4: Update commit description
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
    dst_ops.update_pmtu to control whether we should do neighbor confirm.
    Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.

Fixes: 0dec879f ("net: use dst_confirm_neigh for UDP, RAW, ICMP, L2TP")
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Tested-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add a new function skb_dst_update_pmtu_no_confirm() for callers who need
update pmtu but should not do neighbor confirm.

v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
    dst_ops.update_pmtu to control whether we should do neighbor confirm.
    Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When do IPv6 tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end,
we should not call dst_confirm_neigh() as there is no two-way communication.

Although GTP only support ipv4 right now, and __ip_rt_update_pmtu() does not
call dst_confirm_neigh(), we still set it to false to keep consistency with
IPv6 code.

v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
    dst_ops.update_pmtu to control whether we should do neighbor confirm.
    Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When we do ipv6 gre pmtu update, we will also do neigh confirm currently.
This will cause the neigh cache be refreshed and set to REACHABLE before
xmit.

But if the remote mac address changed, e.g. device is deleted and recreated,
we will not able to notice this and still use the old mac address as the neigh
cache is REACHABLE.

Fix this by disable neigh confirm when do pmtu update

v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
    dst_ops.update_pmtu to control whether we should do neighbor confirm.
    Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.
Reported-by: Jianlin Shi <jishi@redhat.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The MTU update code is supposed to be invoked in response to real
networking events that update the PMTU. In IPv6 PMTU update function
__ip6_rt_update_pmtu() we called dst_confirm_neigh() to update neighbor
confirmed time.

But for tunnel code, it will call pmtu before xmit, like:
  - tnl_update_pmtu()
    - skb_dst_update_pmtu()
      - ip6_rt_update_pmtu()
        - __ip6_rt_update_pmtu()
          - dst_confirm_neigh()

If the tunnel remote dst mac address changed and we still do the neigh
confirm, we will not be able to update neigh cache and ping6 remote
will failed.

So for this ip_tunnel_xmit() case, _EVEN_ if the MTU is changed, we
should not be invoking dst_confirm_neigh() as we have no evidence
of successful two-way communication at this point.

On the other hand it is also important to keep the neigh reachability fresh
for TCP flows, so we cannot remove this dst_confirm_neigh() call.

To fix the issue, we have to add a new bool parameter for dst_ops.update_pmtu
to choose whether we should do neigh update or not. I will add the parameter
in this patch and set all the callers to true to comply with the previous
way, and fix the tunnel code one by one on later patches.

v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
    dst_ops.update_pmtu to control whether we should do neighbor confirm.
    Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.
Suggested-by: David Miller <davem@davemloft.net>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

David Howells says:

====================
rxrpc: Fixes

Here are a couple of bugfixes plus a patch that makes one of the bugfixes
easier:

 (1) Move the ping and mutex unlock on a new call from rxrpc_input_packet()
     into rxrpc_new_incoming_call(), which it calls.  This means the
     lock-unlock section is entirely within the latter function.  This
     simplifies patch (2).

 (2) Don't take the call->user_mutex at all in the softirq path.  Mutexes
     aren't allowed to be taken or released there and a patch was merged
     that caused a warning to be emitted every time this happened.  Looking
     at the code again, it looks like that taking the mutex isn't actually
     necessary, as the value of call->state will block access to the call.

 (3) Fix the incoming call path to check incoming calls earlier to reject
     calls to RPC services for which we don't have a security key of the
     appropriate class.  This avoids an assertion failure if YFS tries
     making a secure call to the kafs cache manager RPC service.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The IP fragment is specified through user-defined field as the first
bit of the first user-defined word. We were previously trying to extract
it from the user-defined mask which could not possibly work. The ip_frag
is also supposed to be a boolean, if we do not cast it as such, we risk
overwriting the next fields in CFP_DATA(6) which would render the rule
inoperative.

Fixes: 7318166c ("net: dsa: bcm_sf2: Add support for ethtool::rxnfc")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The fix on 951c6db9 fixed the issued reported there but introduced
another. When the allocation fails within sctp_stream_init() it is
okay/necessary to free the genradix. But it is also called when adding
new streams, from sctp_send_add_streams() and
sctp_process_strreset_addstrm_in() and in those situations it cannot
just free the genradix because by then it is a fully operational
association.

The fix here then is to only free the genradix in sctp_stream_init()
and on those other call sites  move on with what it already had and let
the subsequent error handling to handle it.

Tested with the reproducers from this report and the previous one,
with lksctp-tools and sctp-tests.

Reported-by: syzbot+9a1bc632e78a1a98488b@syzkaller.appspotmail.com
Fixes: 951c6db9 ("sctp: fix memleak on err handling of stream initialization")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When the size of the receive buffer for a socket is close to 2^31 when
computing if we have enough space in the buffer to copy a packet from
the queue to the buffer we might hit an integer overflow.

When an user set net.core.rmem_default to a value close to 2^31 UDP
packets are dropped because of this overflow. This can be visible, for
instance, with failure to resolve hostnames.

This can be fixed by casting sk_rcvbuf (which is an int) to unsigned
int, similarly to how it is done in TCP.
Signed-off-by: Antonio Messina <amessina@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull xfs fixes from Darrick Wong:
 "Fix a few bugs that could lead to corrupt files, fsck complaints, and
  filesystem crashes:

   - Minor documentation fixes

   - Fix a file corruption due to read racing with an insert range
     operation.

   - Fix log reservation overflows when allocating large rt extents

   - Fix a buffer log item flags check

   - Don't allow administrators to mount with sunit= options that will
     cause later xfs_repair complaints about the root directory being
     suspicious because the fs geometry appeared inconsistent

   - Fix a non-static helper that should have been static"

* tag 'xfs-5.5-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: Make the symbol 'xfs_rtalloc_log_count' static
  xfs: don't commit sunit/swidth updates to disk if that would cause repair failures
  xfs: split the sunit parameter update into two parts
  xfs: refactor agfl length computation function
  libxfs: resync with the userspace libxfs
  xfs: use bitops interface for buf log item AIL flag check
  xfs: fix log reservation overflows when allocating large rt extents
  xfs: stabilize insert range start boundary to avoid COW writeback race
  xfs: fix Sphinx documentation warning

Pull ext4 bug fixes from Ted Ts'o:
 "Ext4 bug fixes, including a regression fix"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: clarify impact of 'commit' mount option
  ext4: fix unused-but-set-variable warning in ext4_add_entry()
  jbd2: fix kernel-doc notation warning
  ext4: use RCU API in debug_print_tree
  ext4: validate the debug_want_extra_isize mount option at parse time
  ext4: reserve revoke credits in __ext4_new_inode
  ext4: unlock on error in ext4_expand_extra_isize()
  ext4: optimize __ext4_check_dir_entry()
  ext4: check for directory entries too close to block end
  ext4: fix ext4_empty_dir() for directories with holes

Pull block fixes from Jens Axboe:
 "Let's try this one again, this time without the compat_ioctl changes.
  We've got those fixed up, but that can go out next week.

  This contains:

   - block queue flush lockdep annotation (Bart)

   - Type fix for bsg_queue_rq() (Bart)

   - Three dasd fixes (Stefan, Jan)

   - nbd deadlock fix (Mike)

   - Error handling bio user map fix (Yang)

   - iocost fix (Tejun)

   - sbitmap waitqueue addition fix that affects the kyber IO scheduler
     (David)"

* tag 'block-5.5-20191221' of git://git.kernel.dk/linux-block:
  sbitmap: only queue kyber's wait callback if not already active
  block: fix memleak when __blk_rq_map_user_iov() is failed
  s390/dasd: fix typo in copyright statement
  s390/dasd: fix memleak in path handling error case
  s390/dasd/cio: Interpret ccw_device_get_mdc return value correctly
  block: Fix a lockdep complaint triggered by request queue flushing
  block: Fix the type of 'sts' in bsg_queue_rq()
  block: end bio with BLK_STS_AGAIN in case of non-mq devs and REQ_NOWAIT
  nbd: fix shutdown and recv work deadlock v2
  iocost: over-budget forced IOs should schedule async delay

Pull KVM fixes from Paolo Bonzini:
 "PPC:
   - Fix a bug where we try to do an ultracall on a system without an
     ultravisor

  KVM:
   - Fix uninitialised sysreg accessor
   - Fix handling of demand-paged device mappings
   - Stop spamming the console on IMPDEF sysregs
   - Relax mappings of writable memslots
   - Assorted cleanups

  MIPS:
   - Now orphan, James Hogan is stepping down

  x86:
   - MAINTAINERS change, so long Radim and thanks for all the fish
   - supported CPUID fixes for AMD machines without SPEC_CTRL"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  MAINTAINERS: remove Radim from KVM maintainers
  MAINTAINERS: Orphan KVM for MIPS
  kvm: x86: Host feature SSBD doesn't imply guest feature AMD_SSBD
  kvm: x86: Host feature SSBD doesn't imply guest feature SPEC_CTRL_SSBD
  KVM: PPC: Book3S HV: Don't do ultravisor calls on systems without ultravisor
  KVM: arm/arm64: Properly handle faulting of device mappings
  KVM: arm64: Ensure 'params' is initialised when looking up sys register
  KVM: arm/arm64: Remove excessive permission check in kvm_arch_prepare_memory_region
  KVM: arm64: Don't log IMP DEF sysreg traps
  KVM: arm64: Sanely ratelimit sysreg messages
  KVM: arm/arm64: vgic: Use wrapper function to lock/unlock all vcpus in kvm_vgic_create()
  KVM: arm/arm64: vgic: Fix potential double free dist->spis in __kvm_vgic_destroy()
  KVM: arm/arm64: Get rid of unused arg in cpu_init_hyp_mode()

Pull RISC-V fixes from Paul Walmsley:
 "Several fixes, and one cleanup, for RISC-V.

  Fixes:

   - Fix an error in a Kconfig file that resulted in an undefined
     Kconfig option "CONFIG_CONFIG_MMU"

   - Fix undefined Kconfig option "CONFIG_CONFIG_MMU"

   - Fix scratch register clearing in M-mode (affects nommu users)

   - Fix a mismerge on my part that broke the build for
     CONFIG_SPARSEMEM_VMEMMAP users

  Cleanup:

   - Move SiFive L2 cache-related code to drivers/soc, per request"

* tag 'riscv/for-v5.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: move sifive_l2_cache.c to drivers/soc
  riscv: define vmemmap before pfn_to_page calls
  riscv: fix scratch register clearing in M-mode.
  riscv: Fix use of undefined config option CONFIG_CONFIG_MMU

Pull networking fixes from David Miller:

 1) Several nf_flow_table_offload fixes from Pablo Neira Ayuso,
    including adding a missing ipv6 match description.

 2) Several heap overflow fixes in mwifiex from qize wang and Ganapathi
    Bhat.

 3) Fix uninit value in bond_neigh_init(), from Eric Dumazet.

 4) Fix non-ACPI probing of nxp-nci, from Stephan Gerhold.

 5) Fix use after free in tipc_disc_rcv(), from Tuong Lien.

 6) Enforce limit of 33 tail calls in mips and riscv JIT, from Paul
    Chaignon.

 7) Multicast MAC limit test is off by one in qede, from Manish Chopra.

 8) Fix established socket lookup race when socket goes from
    TCP_ESTABLISHED to TCP_LISTEN, because there lacks an intervening
    RCU grace period. From Eric Dumazet.

 9) Don't send empty SKBs from tcp_write_xmit(), also from Eric Dumazet.

10) Fix active backup transition after link failure in bonding, from
    Mahesh Bandewar.

11) Avoid zero sized hash table in gtp driver, from Taehee Yoo.

12) Fix wrong interface passed to ->mac_link_up(), from Russell King.

13) Fix DSA egress flooding settings in b53, from Florian Fainelli.

14) Memory leak in gmac_setup_txqs(), from Navid Emamdoost.

15) Fix double free in dpaa2-ptp code, from Ioana Ciornei.

16) Reject invalid MTU values in stmmac, from Jose Abreu.

17) Fix refcount leak in error path of u32 classifier, from Davide
    Caratti.

18) Fix regression causing iwlwifi firmware crashes on boot, from Anders
    Kaseorg.

19) Fix inverted return value logic in llc2 code, from Chan Shu Tak.

20) Disable hardware GRO when XDP is attached to qede, frm Manish
    Chopra.

21) Since we encode state in the low pointer bits, dst metrics must be
    at least 4 byte aligned, which is not necessarily true on m68k. Add
    annotations to fix this, from Geert Uytterhoeven.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (160 commits)
  sfc: Include XDP packet headroom in buffer step size.
  sfc: fix channel allocation with brute force
  net: dst: Force 4-byte alignment of dst_metrics
  selftests: pmtu: fix init mtu value in description
  hv_netvsc: Fix unwanted rx_table reset
  net: phy: ensure that phy IDs are correctly typed
  mod_devicetable: fix PHY module format
  qede: Disable hardware gro when xdp prog is installed
  net: ena: fix issues in setting interrupt moderation params in ethtool
  net: ena: fix default tx interrupt moderation interval
  net/smc: unregister ib devices in reboot_event
  net: stmmac: platform: Fix MDIO init for platforms without PHY
  llc2: Fix return statement of llc_stat_ev_rx_null_dsap_xid_c (and _test_c)
  net: hisilicon: Fix a BUG trigered by wrong bytes_compl
  net: dsa: ksz: use common define for tag len
  s390/qeth: don't return -ENOTSUPP to userspace
  s390/qeth: fix promiscuous mode after reset
  s390/qeth: handle error due to unsupported transport mode
  cxgb4: fix refcount init for TC-MQPRIO offload
  tc-testing: initial tdc selftests for cls_u32
  ...

LTP pipeio_1 test is hanging with v5.5-rc2-385-gb8e382a1,
with read side observing empty pipe and sleeping and write
side running out of space and then sleeping as well. In this
scenario there are 5 writers and 1 reader.

Problem is that after pipe_write() reacquires pipe lock, it
re-checks for empty pipe with potentially stale 'head' and
doesn't wake up read side anymore. pipe->tail can advance
beyond 'head', because there are multiple writers.

Use pipe->head for empty pipe check after reacquiring lock
to observe current state.

Testing: With patch, LTP pipeio_1 ran successfully in loop for 1 hour.
         Without patch it hanged within a minute.

Fixes: 1b6b26ae ("pipe: fix and clarify pipe write wakeup logic")
Reported-by: Rachel Sibley <rasibley@redhat.com>
Signed-off-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'kvm-ppc-fixes-5.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into kvm-master

PPC KVM fix for 5.5

- Fix a bug where we try to do an ultracall on a system without an
  ultravisor.

Radim's kernel.org email is bouncing, which I take as a signal that
he is not really able to deal with KVM at this time.  Make MAINTAINERS
match the effective value of KVM's bus factor.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

I haven't been active for 18 months, and don't have the hardware set up
to test KVM for MIPS, so mark it as orphaned and remove myself as
maintainer. Hopefully somebody from MIPS can pick this up.
Signed-off-by: James Hogan <jhogan@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The description of 'commit' mount option dates back to ext3 times.
Update the description to match current meaning for ext4.
Reported-by: Paul Richards <paul.richards@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20191218111210.14161-1-jack@suse.czSigned-off-by: Theodore Ts'o <tytso@mit.edu>

Warning is found when compile with "-Wunused-but-set-variable":

fs/ext4/namei.c: In function ‘ext4_add_entry’:
fs/ext4/namei.c:2167:23: warning: variable ‘sbi’ set but not used
[-Wunused-but-set-variable]
  struct ext4_sb_info *sbi;
                       ^~~
Fix this by moving the variable @sbi under CONFIG_UNICODE.
Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/cb5eb904-224a-9701-c38f-cb23514b1fff@huawei.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

Pull tracing fixes from Steven Rostedt:

 - Fix memory leak on error path of process_system_preds()

 - Lock inversion fix with updating tgid recording option

 - Fix histogram compare function on big endian machines

 - Fix histogram trigger function on big endian machines

 - Make trace_printk() irq sync on init for kprobe selftest correctness

* tag 'trace-v5.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix endianness bug in histogram trigger
  samples/trace_printk: Wait for IRQ work to finish
  tracing: Fix lock inversion in trace_event_enable_tgid_record()
  tracing: Have the histogram compare functions convert to u64 first
  tracing: Avoid memory leak in process_system_preds()

Pull libnvdimm fix from Dan Williams:
 "A minor regression fix.

  The libnvdimm unit tests were expecting to mock calls to
  ioremap_nocache() which disappeared in v5.5-rc1. This fix has appeared
  in -next and collided with some cleanups that Christoph has planned
  for v5.6, but he will fix up his branch once this goes in.

  Summary:

   - Restore the operation of the libnvdimm unit tests after the removal
     of ioremap_nocache()"

* tag 'libnvdimm-fix-5.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  tools/testing/nvdimm: Fix mock support for ioremap

At least on PA-RISC and s390 synthetic histogram triggers are failing
selftests because trace_event_raw_event_synth() always writes a 64 bit
values, but the reader expects a field->size sized value. On little endian
machines this doesn't hurt, but on big endian this makes the reader always
read zero values.

Link: http://lore.kernel.org/linux-trace-devel/20191218074427.96184-4-svens@linux.ibm.com

Cc: stable@vger.kernel.org
Fixes: 4b147936 ("tracing: Add support for 'synthetic' events")
Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

trace_printk schedules work via irq_work_queue(), but doesn't
wait until it was processed. The kprobe_module.tc testcase does:

:;: "Load module again, which means the event1 should be recorded";:
modprobe trace-printk
grep "event1:" trace

so the grep which checks the trace file might run before the irq work
was processed. Fix this by adding a irq_work_sync().

Link: http://lore.kernel.org/linux-trace-devel/20191218074427.96184-3-svens@linux.ibm.com

Cc: stable@vger.kernel.org
Fixes: af2a0750 ("selftests/ftrace: Improve kprobe on module testcase to load/unload module")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

       Task T2                             Task T3
trace_options_core_write()            subsystem_open()

 mutex_lock(trace_types_lock)           mutex_lock(event_mutex)

 set_tracer_flag()

   trace_event_enable_tgid_record()       mutex_lock(trace_types_lock)

    mutex_lock(event_mutex)

This gives a circular dependency deadlock between trace_types_lock and
event_mutex. To fix this invert the usage of trace_types_lock and
event_mutex in trace_options_core_write(). This keeps the sequence of
lock usage consistent.

Link: http://lkml.kernel.org/r/0101016eef175e38-8ca71caf-a4eb-480d-a1e6-6f0bbc015495-000000@us-west-2.amazonses.com

Cc: stable@vger.kernel.org
Fixes: d914ba37 ("tracing: Add support for recording tgid of tasks")
Signed-off-by: Prateek Sood <prsood@codeaurora.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull s390 fixes from Vasily Gorbik:

 - Fix unwinding from irq context of interrupted user process.

 - Add purgatory build missing symbols check. That helped to uncover and
   fix missing symbols when built with kasan support enabled.

 - Couple of ftrace fixes. Avoid broken stack trace and fix recursion
   loop in function_graph tracer.

* tag 's390-5.5-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/ftrace: save traced function caller
  s390/unwind: stop gracefully at user mode pt_regs in irq stack
  s390/purgatory: do not build purgatory with kcov, kasan and friends
  s390/purgatory: Make sure we fail the build if purgatory has missing symbols
  s390/ftrace: fix endless recursion in function_graph tracer

Pull scheduler fixes from Ingo Molnar:
 "Misc fixes: a (rare) PSI crash fix, a CPU affinity related balancing
  fix, and a toning down of active migration attempts"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/cfs: fix spurious active migration
  sched/fair: Fix find_idlest_group() to handle CPU affinity
  psi: Fix a division error in psi poll()
  sched/psi: Fix sampling error and rare div0 crashes with cgroups and high uptime

Pull perf fixes from Ingo Molnar:
 "Misc fixes: a BTS fix, a PT NMI handling fix, a PMU sysfs fix and an
  SRCU annotation"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Add SRCU annotation for pmus list walk
  perf/x86/intel: Fix PT PMI handling
  perf/x86/intel/bts: Fix the use of page_private()
  perf/x86: Fix potential out-of-bounds access

Merge tag 'kbuild-fixes-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - fix warning in out-of-tree 'make clean'

 - add READELF variable to the top Makefile

 - fix broken builds when LINUX_COMPILE_BY contains a backslash

 - fix build warning in kallsyms

 - fix NULL pointer access in expr_eq() in Kconfig

 - fix missing dependency on rsync in deb-pkg build

 - remove ---help--- from documentation

 - fix misleading documentation about directory descending

* tag 'kbuild-fixes-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: clarify the difference between obj-y and obj-m w.r.t. descending
  kconfig: remove ---help--- from documentation
  scripts: package: mkdebian: add missing rsync dependency
  kconfig: don't crash on NULL expressions in expr_eq()
  scripts/kallsyms: fix offset overflow of kallsyms_relative_base
  mkcompile_h: use printf for LINUX_COMPILE_BY
  mkcompile_h: git rid of UTS_TRUNCATE from LINUX_COMPILE_{BY,HOST}
  x86/boot: kbuild: allow readelf executable to be specified
  kbuild: fix 'No such file or directory' warning when cleaning

Kbuild descends into a directory by either 'y' or 'm', but there is an
important difference.

Kbuild combines the built-in objects into built-in.a in each directory.
The built-in.a in the directory visited by obj-y is merged into the
built-in.a in the parent directory. This merge happens recursively
when Kbuild is ascending back towards the top directory, then built-in
objects are linked into vmlinux eventually. This works properly only
when the Makefile specifying obj-y is reachable by the chain of obj-y.

On the other hand, Kbuild does not take built-in.a from the directory
visited by obj-m. This it, all the objects in that directory are
supposed to be modular. If Kbuild descends into a directory by obj-m,
but the Makefile in the sub-directory specifies obj-y, those objects
are just left orphan.

The current statement "Kbuild only uses this information to decide that
it needs to visit the directory" is misleading. Clarify the difference.
Reported-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Johan Hovold <johan@kernel.org>

Pul parisc fixes from Helge Deller:
 "Two build error fixes, one for the soft_offline_page() parameter
  change and one for a specific KEXEC/KEXEC_FILE configuration, as well
  as a compiler and a linker warning fix"

* 'parisc-5.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Fix compiler warnings in debug_core.c
  parisc: soft_offline_page() now takes the pfn
  parisc: add missing __init annotation
  parisc: fix compilation when KEXEC=n and KEXEC_FILE=y