When stdout output from the selftests tool 'test_maps' gets redirected
into e.g file or pipe, then the output lines increase a lot (from 21
to 33949 lines).  This is caused by the printf that happens before the
fork() call, and there are user-space buffered printf data that seems
to be duplicated into the forked process.

To fix this fflush() stdout before the fork loop in __run_parallel().

Fixes: 1a97cf1f ("selftests/bpf: speedup test_maps")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/159842985651.1050885.2154399297503372406.stgit@firesoul

Commit 32927393 ("sysctl: pass kernel pointers to ->proc_handler")
changed ctl_table.proc_handler to take a kernel pointer. Adjust the
signature of bpf_stats_handler to match ctl_table.proc_handler which
fixes the following sparse warning:

kernel/sysctl.c:226:49: warning: incorrect type in argument 3 (different address spaces)
kernel/sysctl.c:226:49:    expected void *
kernel/sysctl.c:226:49:    got void [noderef] __user *buffer
kernel/sysctl.c:2640:35: warning: incorrect type in initializer (incompatible argument 3 (different address spaces))
kernel/sysctl.c:2640:35:    expected int ( [usertype] *proc_handler )( ... )
kernel/sysctl.c:2640:35:    got int ( * )( ... )

Fixes: 32927393 ("sysctl: pass kernel pointers to ->proc_handler")
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/bpf/20200824142047.22043-1-tklauser@distanz.ch

Commit 643e7233 ("selftests/bpf: Test_progs option for getting number of
tests") introduced ability to getting number of tests, which is targeted
towards scripting.  As demonstrate in the commit the number can be use as a
shell variable for further scripting.

The test_progs program support "flavor", which is detected by the binary
have a "-flavor" in the executable name. One example is test_progs-no_alu32,
which load bpf-progs compiled with disabled alu32, located in dir 'no_alu32/'.

The problem is that invoking a "flavor" binary prints to stdout e.g.:
 "Switching to flavor 'no_alu32' subdirectory..."
Thus, intermixing with the number of tests, making it unusable for scripting.

Fix the issue by only printing "flavor" info when verbose -v option is used.

Fixes: 643e7233 ("selftests/bpf: Test_progs option for getting number of tests")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/159827024012.923543.7104106594870150597.stgit@firesoul

Commit f2e10bff ("bpf: Add support for BPF_OBJ_GET_INFO_BY_FD for bpf_link")
added link query for raw_tp. One of fields in link_info is to
fill a user buffer with tp_name. The Scurrent checking only
declares "ulen && !ubuf" as invalid. So "!ulen && ubuf" will be
valid. Later on, we do "copy_to_user(ubuf, tp_name, ulen - 1)" which
may overwrite user memory incorrectly.

This patch fixed the problem by disallowing "!ulen && ubuf" case as well.

Fixes: f2e10bff ("bpf: Add support for BPF_OBJ_GET_INFO_BY_FD for bpf_link")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200821191054.714731-1-yhs@fb.com

Simon Wunderlich says:

====================
Here are some batman-adv bugfixes:

 - Avoid uninitialized memory access when handling DHCP, by Sven Eckelmann

 - Fix check for own OGM in OGM receive handler, by Linus Luessing

 - Fix netif_rx access for non-interrupt context in BLA, by Jussi Kivilinna
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

check_fcs() was returning bool as 0/1, which was a sign that the sense
 of the function was unclear: false was good, which doesn't really match
 a name like 'check_$thing'.  So rename it to ef100_has_fcs_error(), and
 use proper booleans in the return statements.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Every iteration of for_each_available_child_of_node() decrements
the reference count of the previous node, however when control
is transferred from the middle of the loop, as in the case of
a return or break or goto, there is no decrement thus ultimately
resulting in a memory leak.

Fix a potential memory leak in felix.c by inserting of_node_put()
before the return statement.

Issue found with Coccinelle.
Signed-off-by: Sumera Priyadarsini <sylphrenadin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix spelling mistake documenation -> documentation.

Fixes: 5a18bb14 ("dt-bindings: net: dsa: Let dsa.txt refer to dsa.yaml")
Signed-off-by: Kurt Kanzenbach <kurt@kmk-computers.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

When make_rate() fails, vcc should be freed just
like other error paths in fs_open().
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

When devm_gpiod_get_optional() fails, bus should be
freed just like when of_mdiobus_register() fails.

Fixes: 1bddd96c ("net: arc_emac: support the phy reset for emac driver")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

When down_killable() fails, skb_resp should be freed
just like when st95hf_spi_send() fails.
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

Florian Fainelli says:

====================
MAINTAINERS: Remove self from PHY LIBRARY

This patch series aims at allowing myself to keep track of the Ethernet
PHY and MDIO bus drivers that I authored or contributed to without
being listed as a maintainer in the PHY library anymore.

Thank you for the fish, I will still be around.

This builds on top of Andrew's series:
https://lore.kernel.org/netdev/20200822180611.2576807-1-andrew@lunn.ch/
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

My last significant achievements to the PHY library was ensuring we
would have small bus factor by having Andrew and Heiner added. The world
has moved on past 1G, but I have not, so let more competent maintainers
take over.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add an entry for the Broadcom Ethernet PHY drivers covering the BCM63xx,
BCM7xxx, BCM87xx, BCM54140, BCM84881, the venerable broadcom.c driver
and the companion library files.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In preparation for removing myself from the PHYLIB entry, add the UniMAC
MDIO controller files (DT binding, driver and platform_data header) to
the GENET entry. The UniMAC MDIO controller is essential to the GENET
operation, therefore it makes sense to group them together.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When the DT binding was added in aab5127d ("Documentation: add
Device tree bindings for Broadcom GENET"), the file was not explicitly
listed under the GENET MAINTAINERS section, do that now.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When the binding was added with 967dd82f ("net: dsa: b53: Add
support for Broadcom RoboSwitch"), it was not explicitly added to the
B53 MAINTAINERS file section, add it now.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When commit b0ba512e ("net: bcmgenet: enable driver to work without
a device tree") added include/linux/platform_data/bcmgenet.h, the file
was not added to the GENET MAINTAINERS file section, add it now.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Clang warns:

drivers/net/dsa/sja1105/sja1105_main.c:3418:38: warning: address of
array 'match->compatible' will always evaluate to 'true'
[-Wpointer-bool-conversion]
        for (match = sja1105_dt_ids; match->compatible; match++) {
        ~~~                          ~~~~~~~^~~~~~~~~~
1 warning generated.

We should check the value of the first character in compatible to see if
it is empty or not. This matches how the rest of the tree iterates over
IDs.

Fixes: 0b0e2997 ("net: dsa: sja1105: use detected device id instead of DT one on mismatch")
Link: https://github.com/ClangBuiltLinux/linux/issues/1139Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The function consume_skb is only meaningful when tracing is enabled.
This patch makes it conditional on CONFIG_TRACEPOINTS.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

The underlying Ethernet device may request necessary tailroom to be
allocated by setting needed_tailroom. This driver should also set
needed_tailroom to request the tailroom needed by the underlying
Ethernet device to be allocated.

Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch fixes two main problems seen when removing NetLabel
mappings: memory leaks and potentially extra audit noise.

The memory leaks are caused by not properly free'ing the mapping's
address selector struct when free'ing the entire entry as well as
not properly cleaning up a temporary mapping entry when adding new
address selectors to an existing entry.  This patch fixes both these
problems such that kmemleak reports no NetLabel associated leaks
after running the SELinux test suite.

The potentially extra audit noise was caused by the auditing code in
netlbl_domhsh_remove_entry() being called regardless of the entry's
validity.  If another thread had already marked the entry as invalid,
but not removed/free'd it from the list of mappings, then it was
possible that an additional mapping removal audit record would be
generated.  This patch fixes this by returning early from the removal
function when the entry was previously marked invalid.  This change
also had the side benefit of improving the code by decreasing the
indentation level of large chunk of code by one (accounting for most
of the diffstat).

Fixes: 63c41688 ("netlabel: Add network address selectors to the NetLabel/LSM domain mapping")
Reported-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

With disabling bh in the whole sctp_get_port_local(), when
snum == 0 and too many ports have been used, the do-while
loop will take the cpu for a long time and cause cpu stuck:

  [ ] watchdog: BUG: soft lockup - CPU#11 stuck for 22s!
  [ ] RIP: 0010:native_queued_spin_lock_slowpath+0x4de/0x940
  [ ] Call Trace:
  [ ]  _raw_spin_lock+0xc1/0xd0
  [ ]  sctp_get_port_local+0x527/0x650 [sctp]
  [ ]  sctp_do_bind+0x208/0x5e0 [sctp]
  [ ]  sctp_autobind+0x165/0x1e0 [sctp]
  [ ]  sctp_connect_new_asoc+0x355/0x480 [sctp]
  [ ]  __sctp_connect+0x360/0xb10 [sctp]

There's no need to disable bh in the whole function of
sctp_get_port_local. So fix this cpu stuck by removing
local_bh_disable() called at the beginning, and using
spin_lock_bh() instead.

The same thing was actually done for inet_csk_get_port() in
Commit ea8add2b ("tcp/dccp: better use of ephemeral
ports in bind()").

Thanks to Marcelo for pointing the buggy code out.

v1->v2:
  - use cond_resched() to yield cpu to other tasks if needed,
    as Eric noticed.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Reported-by: Ying Xu <yinxu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When this driver is built as a module, I cannot rmmod it after insmoding
it.
This is because that this driver calls ravb_mdio_init() at the time of
probe, and module->refcnt is incremented by alloc_mdio_bitbang() called
after that.
Therefore, even if ifup is not performed, the driver is in use and rmmod
cannot be performed.

$ lsmod
Module                  Size  Used by
ravb                   40960  1
$ rmmod ravb
rmmod: ERROR: Module ravb is in use

Call ravb_mdio_init() at open and free_mdio_bitbang() at close, thereby
rmmod is possible in the ifdown state.

Fixes: c156633f ("Renesas Ethernet AVB driver proper")
Signed-off-by: Yuusuke Ashizuka <ashiduka@fujitsu.com>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit 32927393 ("sysctl: pass kernel pointers to ->proc_handler")
changed ndisc_ifinfo_sysctl_change to take a kernel pointer. Adjust its
prototype in net/ndisc.h as well to fix the following sparse warning:

net/ipv6/ndisc.c:1838:5: error: symbol 'ndisc_ifinfo_sysctl_change' redeclared with different type (incompatible argument 3 (different address spaces)):
net/ipv6/ndisc.c:1838:5:    int extern [addressable] [signed] [toplevel] ndisc_ifinfo_sysctl_change( ... )
net/ipv6/ndisc.c: note: in included file (through include/net/ipv6.h):
./include/net/ndisc.h:496:5: note: previously declared as:
./include/net/ndisc.h:496:5:    int extern [addressable] [signed] [toplevel] ndisc_ifinfo_sysctl_change( ... )
net/ipv6/ndisc.c: note: in included file (through include/net/ip6_route.h):

Fixes: 32927393 ("sysctl: pass kernel pointers to ->proc_handler")
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

The following patchset contains Netfilter fixes for net:

1) Don't flag SCTP heartbeat as invalid for re-used connections,
   from Florian Westphal.

2) Bogus overlap report due to rbtree tree rotations, from Stefano Brivio.

3) Detect partial overlap with start end point match, also from Stefano.

4) Skip netlink dump of NFTA_SET_USERDATA is unset.

5) Incorrect nft_list_attributes enumeration definition.

6) Missing zeroing before memcpy to destination register, also
   from Florian.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

When devm_kcalloc() fails, dev should be freed just
like what we've done in the subsequent error paths.

Fixes: 7b78be48 ("net: systemport: Dynamically allocate number of TX rings")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

hns_nic_dev_probe allocates ndev, but not free it on
two error handling paths, which may lead to memleak.

Fixes: 63434888 ("net: hns: net: hns: enet adds support of acpi")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull powerpc fixes from Michael Ellerman:

 - Add perf support for emitting extended registers for power10.

 - A fix for CPU hotplug on pseries, where on large/loaded systems we
   may not wait long enough for the CPU to be offlined, leading to
   crashes.

 - Addition of a raw cputable entry for Power10, which is not required
   to boot, but is required to make our PMU setup work correctly in
   guests.

 - Three fixes for the recent changes on 32-bit Book3S to move modules
   into their own segment for strict RWX.

 - A fix for a recent change in our powernv PCI code that could lead to
   crashes.

 - A change to our perf interrupt accounting to avoid soft lockups when
   using some events, found by syzkaller.

 - A change in the way we handle power loss events from the hypervisor
   on pseries. We no longer immediately shut down if we're told we're
   running on a UPS.

 - A few other minor fixes.

Thanks to Alexey Kardashevskiy, Andreas Schwab, Aneesh Kumar K.V, Anju T
Sudhakar, Athira Rajeev, Christophe Leroy, Frederic Barrat, Greg Kurz,
Kajol Jain, Madhavan Srinivasan, Michael Neuling, Michael Roth,
Nageswara R Sastry, Oliver O'Halloran, Thiago Jung Bauermann,
Vaidyanathan Srinivasan, Vasant Hegde.

* tag 'powerpc-5.9-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/perf/hv-24x7: Move cpumask file to top folder of hv-24x7 driver
  powerpc/32s: Fix module loading failure when VMALLOC_END is over 0xf0000000
  powerpc/pseries: Do not initiate shutdown when system is running on UPS
  powerpc/perf: Fix soft lockups due to missed interrupt accounting
  powerpc/powernv/pci: Fix possible crash when releasing DMA resources
  powerpc/pseries/hotplug-cpu: wait indefinitely for vCPU death
  powerpc/32s: Fix is_module_segment() when MODULES_VADDR is defined
  powerpc/kasan: Fix KASAN_SHADOW_START on BOOK3S_32
  powerpc/fixmap: Fix the size of the early debug area
  powerpc/pkeys: Fix build error with PPC_MEM_KEYS disabled
  powerpc/kernel: Cleanup machine check function declarations
  powerpc: Add POWER10 raw mode cputable entry
  powerpc/perf: Add extended regs support for power10 platform
  powerpc/perf: Add support for outputting extended regs in perf intr_regs
  powerpc: Fix P10 PVR revision in /proc/cpuinfo for SMT4 cores

Pull x86 fix from Thomas Gleixner:
 "A single fix for x86 which removes the RDPID usage from the paranoid
  entry path and unconditionally uses LSL to retrieve the CPU number.

  RDPID depends on MSR_TSX_AUX. KVM has an optmization to avoid
  expensive MRS read/writes on VMENTER/EXIT. It caches the MSR values
  and restores them either when leaving the run loop, on preemption or
  when going out to user space. MSR_TSX_AUX is part of that lazy MSR
  set, so after writing the guest value and before the lazy restore any
  exception using the paranoid entry will read the guest value and use
  it as CPU number to retrieve the GSBASE value for the current CPU when
  FSGSBASE is enabled. As RDPID is only used in that particular entry
  path, there is no reason to burden VMENTER/EXIT with two extra MSR
  writes. Remove the RDPID optimization, which is not even backed by
  numbers from the paranoid entry path instead"

* tag 'x86-urgent-2020-08-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/entry/64: Do not use RDPID in paranoid entry to accomodate KVM

Pull x86 perf fix from Thomas Gleixner:
 "A single update for perf on x86 which has support for the broken down
  bandwith counters"

* tag 'perf-urgent-2020-08-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel/uncore: Add BW counters for GT, IA and IO breakdown

Pull EFI fixes from Thomas Gleixner:

 - Enforce NX on RO data in mixed EFI mode

 - Destroy workqueue in an error handling path to prevent UAF

 - Stop argument parser at '--' which is the delimiter for init

 - Treat a NULL command line pointer as empty instead of dereferncing it
   unconditionally.

 - Handle an unterminated command line correctly

 - Cleanup the 32bit code leftovers and remove obsolete documentation

* tag 'efi-urgent-2020-08-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Documentation: efi: remove description of efi=old_map
  efi/x86: Move 32-bit code into efi_32.c
  efi/libstub: Handle unterminated cmdline
  efi/libstub: Handle NULL cmdline
  efi/libstub: Stop parsing arguments at "--"
  efi: add missed destroy_workqueue when efisubsys_init fails
  efi/x86: Mark kernel rodata non-executable for mixed mode

Pull entry fix from Thomas Gleixner:
 "A single bug fix for the common entry code.

  The transcription of the x86 version messed up the reload of the
  syscall number from pt_regs after ptrace and seccomp which breaks
  syscall number rewriting"

* tag 'core-urgent-2020-08-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  core/entry: Respect syscall number rewrites

Pull EDAC fix from Borislav Petkov:
 "A single fix correcting a reversed error severity determination check
  which lead to a recoverable error getting marked as fatal, by Tony
  Luck"

* tag 'edac_urgent_for_v5.9_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras:
  EDAC/{i7core,sb,pnd2,skx}: Fix error event severity

Pull networking fixes from David Miller:
 "Nothing earth shattering here, lots of small fixes (f.e. missing RCU
  protection, bad ref counting, missing memset(), etc.) all over the
  place:

   1) Use get_file_rcu() in task_file iterator, from Yonghong Song.

   2) There are two ways to set remote source MAC addresses in macvlan
      driver, but only one of which validates things properly. Fix this.
      From Alvin Šipraga.

   3) Missing of_node_put() in gianfar probing, from Sumera
      Priyadarsini.

   4) Preserve device wanted feature bits across multiple netlink
      ethtool requests, from Maxim Mikityanskiy.

   5) Fix rcu_sched stall in task and task_file bpf iterators, from
      Yonghong Song.

   6) Avoid reset after device destroy in ena driver, from Shay
      Agroskin.

   7) Missing memset() in netlink policy export reallocation path, from
      Johannes Berg.

   8) Fix info leak in __smc_diag_dump(), from Peilin Ye.

   9) Decapsulate ECN properly for ipv6 in ipv4 tunnels, from Mark
      Tomlinson.

  10) Fix number of data stream negotiation in SCTP, from David Laight.

  11) Fix double free in connection tracker action module, from Alaa
      Hleihel.

  12) Don't allow empty NHA_GROUP attributes, from Nikolay Aleksandrov"

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (46 commits)
  net: nexthop: don't allow empty NHA_GROUP
  bpf: Fix two typos in uapi/linux/bpf.h
  net: dsa: b53: check for timeout
  tipc: call rcu_read_lock() in tipc_aead_encrypt_done()
  net/sched: act_ct: Fix skb double-free in tcf_ct_handle_fragments() error flow
  net: sctp: Fix negotiation of the number of data streams.
  dt-bindings: net: renesas, ether: Improve schema validation
  gre6: Fix reception with IP6_TNL_F_RCV_DSCP_COPY
  hv_netvsc: Fix the queue_mapping in netvsc_vf_xmit()
  hv_netvsc: Remove "unlikely" from netvsc_select_queue
  bpf: selftests: global_funcs: Check err_str before strstr
  bpf: xdp: Fix XDP mode when no mode flags specified
  selftests/bpf: Remove test_align leftovers
  tools/resolve_btfids: Fix sections with wrong alignment
  net/smc: Prevent kernel-infoleak in __smc_diag_dump()
  sfc: fix build warnings on 32-bit
  net: phy: mscc: Fix a couple of spelling mistakes "spcified" -> "specified"
  libbpf: Fix map index used in error message
  net: gemini: Fix missing free_netdev() in error path of gemini_ethernet_port_probe()
  net: atlantic: Use readx_poll_timeout() for large timeout
  ...

Pull epoll fixes from Al Viro:
 "Fix reference counting and clean up exit paths"

* 'work.epoll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  do_epoll_ctl(): clean the failure exits up a bit
  epoll: Keep a reference on files added to the check list

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

When adding a new fd to an epoll, and that this new fd is an
epoll fd itself, we recursively scan the fds attached to it
to detect cycles, and add non-epool files to a "check list"
that gets subsequently parsed.

However, this check list isn't completely safe when deletions
can happen concurrently. To sidestep the issue, make sure that
a struct file placed on the check list sees its f_count increased,
ensuring that a concurrent deletion won't result in the file
disapearing from under our feet.

Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Currently the nexthop code will use an empty NHA_GROUP attribute, but it
requires at least 1 entry in order to function properly. Otherwise we
end up derefencing null or random pointers all over the place due to not
having any nh_grp_entry members allocated, nexthop code relies on having at
least the first member present. Empty NHA_GROUP doesn't make any sense so
just disallow it.
Also add a WARN_ON for any future users of nexthop_create_group().

 BUG: kernel NULL pointer dereference, address: 0000000000000080
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: 0000 [#1] SMP
 CPU: 0 PID: 558 Comm: ip Not tainted 5.9.0-rc1+ #93
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-2.fc32 04/01/2014
 RIP: 0010:fib_check_nexthop+0x4a/0xaa
 Code: 0f 84 83 00 00 00 48 c7 02 80 03 f7 81 c3 40 80 fe fe 75 12 b8 ea ff ff ff 48 85 d2 74 6b 48 c7 02 40 03 f7 81 c3 48 8b 40 10 <48> 8b 80 80 00 00 00 eb 36 80 78 1a 00 74 12 b8 ea ff ff ff 48 85
 RSP: 0018:ffff88807983ba00 EFLAGS: 00010213
 RAX: 0000000000000000 RBX: ffff88807983bc00 RCX: 0000000000000000
 RDX: ffff88807983bc00 RSI: 0000000000000000 RDI: ffff88807bdd0a80
 RBP: ffff88807983baf8 R08: 0000000000000dc0 R09: 000000000000040a
 R10: 0000000000000000 R11: ffff88807bdd0ae8 R12: 0000000000000000
 R13: 0000000000000000 R14: ffff88807bea3100 R15: 0000000000000001
 FS:  00007f10db393700(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000080 CR3: 000000007bd0f004 CR4: 00000000003706f0
 Call Trace:
  fib_create_info+0x64d/0xaf7
  fib_table_insert+0xf6/0x581
  ? __vma_adjust+0x3b6/0x4d4
  inet_rtm_newroute+0x56/0x70
  rtnetlink_rcv_msg+0x1e3/0x20d
  ? rtnl_calcit.isra.0+0xb8/0xb8
  netlink_rcv_skb+0x5b/0xac
  netlink_unicast+0xfa/0x17b
  netlink_sendmsg+0x334/0x353
  sock_sendmsg_nosec+0xf/0x3f
  ____sys_sendmsg+0x1a0/0x1fc
  ? copy_msghdr_from_user+0x4c/0x61
  ___sys_sendmsg+0x63/0x84
  ? handle_mm_fault+0xa39/0x11b5
  ? sockfd_lookup_light+0x72/0x9a
  __sys_sendmsg+0x50/0x6e
  do_syscall_64+0x54/0xbe
  entry_SYSCALL_64_after_hwframe+0x44/0xa9
 RIP: 0033:0x7f10dacc0bb7
 Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb cd 66 0f 1f 44 00 00 8b 05 9a 4b 2b 00 85 c0 75 2e 48 63 ff 48 63 d2 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 b1 f2 2a 00 f7 d8 64 89 02 48
 RSP: 002b:00007ffcbe628bf8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
 RAX: ffffffffffffffda RBX: 00007ffcbe628f80 RCX: 00007f10dacc0bb7
 RDX: 0000000000000000 RSI: 00007ffcbe628c60 RDI: 0000000000000003
 RBP: 000000005f41099c R08: 0000000000000001 R09: 0000000000000008
 R10: 00000000000005e9 R11: 0000000000000246 R12: 0000000000000000
 R13: 0000000000000000 R14: 00007ffcbe628d70 R15: 0000563a86c6e440
 Modules linked in:
 CR2: 0000000000000080

CC: David Ahern <dsahern@gmail.com>
Fixes: 430a0491 ("nexthop: Add support for nexthop groups")
Reported-by: syzbot+a61aa19b0c14c8770bd9@syzkaller.appspotmail.com
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'kbuild-fixes-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - move -Wsign-compare warning from W=2 to W=3

 - fix the keyword _restrict to __restrict in genksyms

 - fix more bugs in qconf

* tag 'kbuild-fixes-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kconfig: qconf: replace deprecated QString::sprintf() with QTextStream
  kconfig: qconf: remove redundant help in the info view
  kconfig: qconf: remove qInfo() to get back Qt4 support
  kconfig: qconf: remove unused colNr
  kconfig: qconf: fix the popup menu in the ConfigInfoView window
  kconfig: qconf: fix signal connection to invalid slots
  genksyms: keywords: Use __restrict not _restrict
  kbuild: remove redundant patterns in filter/filter-out
  extract-cert: add static to local data
  Makefile.extrawarn: Move sign-compare from W=2 to W=3