syzbot found its way in 86_fsgsbase_read_task() and triggered this oops:

   KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
   CPU: 0 PID: 6866 Comm: syz-executor262 Not tainted 5.8.0-syzkaller #0
   RIP: 0010:x86_fsgsbase_read_task+0x16d/0x310 arch/x86/kernel/process_64.c:393
   Call Trace:
     putreg32+0x3ab/0x530 arch/x86/kernel/ptrace.c:876
     genregs32_set arch/x86/kernel/ptrace.c:1026 [inline]
     genregs32_set+0xa4/0x100 arch/x86/kernel/ptrace.c:1006
     copy_regset_from_user include/linux/regset.h:326 [inline]
     ia32_arch_ptrace arch/x86/kernel/ptrace.c:1061 [inline]
     compat_arch_ptrace+0x36c/0xd90 arch/x86/kernel/ptrace.c:1198
     __do_compat_sys_ptrace kernel/ptrace.c:1420 [inline]
     __se_compat_sys_ptrace kernel/ptrace.c:1389 [inline]
     __ia32_compat_sys_ptrace+0x220/0x2f0 kernel/ptrace.c:1389
     do_syscall_32_irqs_on arch/x86/entry/common.c:84 [inline]
     __do_fast_syscall_32+0x57/0x80 arch/x86/entry/common.c:126
     do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:149
     entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

This can happen if ptrace() or sigreturn() pokes an LDT selector into FS
or GS for a task with no LDT and something tries to read the base before
a return to usermode notices the bad selector and fixes it.

The fix is to make sure ldt pointer is not NULL.

Fixes: 07e1d88a ("x86/fsgsbase/64: Fix ptrace() to read the FS/GS base accurately")
Co-developed-by: Jann Horn <jannh@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Chang S. Bae <chang.seok.bae@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Markus T Metzger <markus.t.metzger@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull crypto fix from Herbert Xu:
 "This fixes a regression in af_alg"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: algif_aead - fix uninitialized ctx->init

Pull module updates from Jessica Yu:
 "The most important change would be Christoph Hellwig's patch
  implementing proprietary taint inheritance, in an effort to discourage
  the creation of GPL "shim" modules that interface between GPL symbols
  and proprietary symbols.

  Summary:

   - Have modules that use symbols from proprietary modules inherit the
     TAINT_PROPRIETARY_MODULE taint, in an effort to prevent GPL shim
     modules that are used to circumvent _GPL exports. These are modules
     that claim to be GPL licensed while also using symbols from
     proprietary modules. Such modules will be rejected while non-GPL
     modules will inherit the proprietary taint.

   - Module export space cleanup. Unexport symbols that are unused
     outside of module.c or otherwise used in only built-in code"

* tag 'modules-for-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  modules: inherit TAINT_PROPRIETARY_MODULE
  modules: return licensing information from find_symbol
  modules: rename the licence field in struct symsearch to license
  modules: unexport __module_address
  modules: unexport __module_text_address
  modules: mark each_symbol_section static
  modules: mark find_symbol static
  modules: mark ref_module static
  modules: linux/moduleparam.h: drop duplicated word in a comment

Pull Kconfig updates from Masahiro Yamada:

 - remove '---help---' keyword support

 - fix mouse events for 'menuconfig' symbols in search view of qconf

 - code cleanups of qconf

* tag 'kconfig-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (24 commits)
  kconfig: qconf: move setOptionMode() to ConfigList from ConfigView
  kconfig: qconf: do not limit the pop-up menu to the first row
  kconfig: qconf: refactor icon setups
  kconfig: qconf: remove unused voidPix, menuInvPix
  kconfig: qconf: remove ConfigItem::text/setText
  kconfig: qconf: remove ConfigList::addColumn/removeColumn
  kconfig: qconf: remove ConfigItem::pixmap/setPixmap
  kconfig: qconf: drop more localization code
  kconfig: qconf: remove 'parent' from ConfigList::updateMenuList()
  kconfig: qconf: remove unused argument from ConfigView::updateList()
  kconfig: qconf: remove unused argument from ConfigList::updateList()
  kconfig: qconf: omit parent to QHBoxLayout()
  kconfig: qconf: remove name from ConfigSearchWindow constructor
  kconfig: qconf: remove unused ConfigList::listView()
  kconfig: qconf: overload addToolBar() to create and insert toolbar
  kconfig: qconf: remove toolBar from ConfigMainWindow members
  kconfig: qconf: use 'menu' variable for (QMenu *)
  kconfig: qconf: do not use 'menu' variable for (QMenuBar *)
  kconfig: qconf: remove ->addSeparator() to menuBar
  kconfig: add 'static' to some file-local data
  ...

ConfigView::setOptionMode() only gets access to the 'list' member.

Move it to the more relevant ConfigList class.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

If you right-click the first row in the option tree, the pop-up menu
shows up, but if you right-click the second row or below, the event
is ignored due to the following check:

  if (e->y() <= header()->geometry().bottom()) {

Perhaps, the intention was to show the pop-menu only when the tree
header was right-clicked, but this handler is not called in that case.

Since the origin of e->y() starts from the bottom of the header,
this check is odd.

Going forward, you can right-click anywhere in the tree to get the
pop-up menu.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

These icon data are used by ConfigItem, but stored in each instance
of ConfigView. There is no point to keep the same data in each of 3
instances, "menu", "config", and "search".

Move the icon data to the more relevant ConfigItem class, and make
them static members.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

These are initialized, but not used by anyone.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Use QTreeWidgetItem::text/setText directly
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Use QTreeView::showColumn/hideColumn directly.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Use QTreeWidgetItem::icon/setIcon directly.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This is a remnant of commit 694c49a7 ("kconfig: drop localization
support").

Get it back to the code prior to commit 3b9fa093 ("[PATCH] Kconfig
i18n support").
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

All the call-sites of this function pass 'this' to the first argument.

So, 'parent' is always the 'this' pointer.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Now that ConfigList::updateList() takes no argument, the 'item' argument
ConfigView::updateList() is no longer used.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This function allocates 'item' before using it, so the argument 'item'
is always shadowed.

Remove the meaningless argument.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Instead of passing 0 (i.e. nullptr), leave it empty.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This constructor is only called with "search" as the second argument.

Hard-code the name in the constructor, and drop it from the function
argument.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

I do not know how this function can be useful. In fact, it is unsed.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Use the overloaded function, addToolBar(const QString &title)
to create a QToolBar object, setting its window title, and inserts
it into the toolbar area.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This pointer is only used in the ConfigMainWindow constructor.

Drop it from the private members.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The variable 'config' for the file menu is inconsistent.

You do not need to use different variables. Use 'menu' for every menu.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

I think it is a bit confusing to use 'menu' to hold a QMenuBar pointer.
I want to use 'menu' for a QMenu pointer.

You do not need to use a local variable here. Use menuBar() directly.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

I do not understand the purpose of this ->addSeparator().
It does not make any difference.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Fix some warnings from sparce like follows:

  warning: symbol '...' was not declared. Should it be static?
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

On menu properties mouse events didn't do anything in search view
(listMode).

As there are no menus in listMode we can add an exception in tests to
always change the value on mouse events if we are in listMode.
Signed-off-by: Maxime Chretien <maxime.chretien@bootlin.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Constify arrays as well as strings.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This reverts commit 84af7a61.

The conversion is done.

Cc: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The conversion is done. No more user of '---help---'.

Cc: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Pull networking fixes from David Miller:
 "Some merge window fallout, some longer term fixes:

   1) Handle headroom properly in lapbether and x25_asy drivers, from
      Xie He.

   2) Fetch MAC address from correct r8152 device node, from Thierry
      Reding.

   3) In the sw kTLS path we should allow MSG_CMSG_COMPAT in sendmsg,
      from Rouven Czerwinski.

   4) Correct fdputs in socket layer, from Miaohe Lin.

   5) Revert troublesome sockptr_t optimization, from Christoph Hellwig.

   6) Fix TCP TFO key reading on big endian, from Jason Baron.

   7) Missing CAP_NET_RAW check in nfc, from Qingyu Li.

   8) Fix inet fastreuse optimization with tproxy sockets, from Tim
      Froidcoeur.

   9) Fix 64-bit divide in new SFC driver, from Edward Cree.

  10) Add a tracepoint for prandom_u32 so that we can more easily
      perform usage analysis. From Eric Dumazet.

  11) Fix rwlock imbalance in AF_PACKET, from John Ogness"

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (49 commits)
  net: openvswitch: introduce common code for flushing flows
  af_packet: TPACKET_V3: fix fill status rwlock imbalance
  random32: add a tracepoint for prandom_u32()
  Revert "ipv4: tunnel: fix compilation on ARCH=um"
  net: accept an empty mask in /sys/class/net/*/queues/rx-*/rps_cpus
  net: ethernet: stmmac: Disable hardware multicast filter
  net: stmmac: dwmac1000: provide multicast filter fallback
  ipv4: tunnel: fix compilation on ARCH=um
  vsock: fix potential null pointer dereference in vsock_poll()
  sfc: fix ef100 design-param checking
  net: initialize fastreuse on inet_inherit_port
  net: refactor bind_bucket fastreuse into helper
  net: phy: marvell10g: fix null pointer dereference
  net: Fix potential memory leak in proto_register()
  net: qcom/emac: add missed clk_disable_unprepare in error path of emac_clks_phase1_init
  ionic_lif: Use devm_kcalloc() in ionic_qcq_alloc()
  net/nfc/rawsock.c: add CAP_NET_RAW check.
  hinic: fix strncpy output truncated compile warnings
  drivers/net/wan/x25_asy: Added needed_headroom and a skb->len check
  net/tls: Fix kmap usage
  ...

Pull i2c updates from Wolfram Sang:

 - bus recovery can now be given a pinctrl handle and the I2C core will
   do all the steps to switch to/from GPIO which can save quite some
   boilerplate code from drivers

 - "fallthrough" conversion

 - driver updates, mostly ID additions

* 'i2c/for-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (32 commits)
  i2c: iproc: fix race between client unreg and isr
  i2c: eg20t: use generic power management
  i2c: eg20t: Drop PCI wakeup calls from .suspend/.resume
  i2c: mediatek: Fix i2c_spec_values description
  i2c: mediatek: Add i2c compatible for MediaTek MT8192
  dt-bindings: i2c: update bindings for MT8192 SoC
  i2c: mediatek: Add access to more than 8GB dram in i2c driver
  i2c: mediatek: Add apdma sync in i2c driver
  i2c: i801: Add support for Intel Tiger Lake PCH-H
  i2c: i801: Add support for Intel Emmitsburg PCH
  i2c: bcm2835: Replace HTTP links with HTTPS ones
  Documentation: i2c: dev: 'block process call' is supported
  i2c: at91: Move to generic GPIO bus recovery
  i2c: core: treat EPROBE_DEFER when acquiring SCL/SDA GPIOs
  i2c: core: add generic I2C GPIO recovery
  dt-bindings: i2c: add generic properties for GPIO bus recovery
  i2c: rcar: avoid race when unregistering slave
  i2c: tegra: Avoid tegra_i2c_init_dma() for Tegra210 vi i2c
  i2c: tegra: Fix runtime resume to re-init VI I2C
  i2c: tegra: Fix the error path in tegra_i2c_runtime_resume
  ...

To avoid some issues, for example RCU usage warning and double free,
we should flush the flows under ovs_lock. This patch refactors
table_instance_destroy and introduces table_instance_flow_flush
which can be invoked by __dp_destroy or ovs_flow_tbl_flush.

Fixes: 50b0e61b ("net: openvswitch: fix possible memleak on destroy flow-table")
Reported-by: Johan Knöös <jknoos@google.com>
Reported-at: https://mail.openvswitch.org/pipermail/ovs-discuss/2020-August/050489.htmlSigned-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

After @blk_fill_in_prog_lock is acquired there is an early out vnet
situation that can occur. In that case, the rwlock needs to be
released.

Also, since @blk_fill_in_prog_lock is only acquired when @tp_version
is exactly TPACKET_V3, only release it on that exact condition as
well.

And finally, add sparse annotation so that it is clearer that
prb_fill_curr_block() and prb_clear_blk_fill_status() are acquiring
and releasing @blk_fill_in_prog_lock, respectively. sparse is still
unable to understand the balance, but the warnings are now on a
higher level that make more sense.

Fixes: 632ca50f ("af_packet: TPACKET_V3: replace busy-wait loop")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There has been some heat around prandom_u32() lately, and some people
were wondering if there was a simple way to determine how often
it was used, before considering making it maybe 10 times more expensive.

This tracepoint exports the generated pseudo random value.

Tested:

perf list | grep prandom_u32
  random:prandom_u32                                 [Tracepoint event]

perf record -a [-g] [-C1] -e random:prandom_u32 sleep 1
[ perf record: Woken up 0 times to write data ]
[ perf record: Captured and wrote 259.748 MB perf.data (924087 samples) ]

perf report --nochildren
    ...
    97.67%  ksoftirqd/1     [kernel.vmlinux]  [k] prandom_u32
            |
            ---prandom_u32
               prandom_u32
               |
               |--48.86%--tcp_v4_syn_recv_sock
               |          tcp_check_req
               |          tcp_v4_rcv
               |          ...
                --48.81%--tcp_conn_request
                          tcp_v4_conn_request
                          tcp_rcv_state_process
                          ...
perf script
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull documentation fixes from Jonathan Corbet:
 "A handful of obvious fixes that wandered in during the merge window"

* tag 'docs-5.9-2' of git://git.lwn.net/linux:
  Documentation/locking/locktypes: fix the typo
  doc/zh_CN: resolve undefined label warning in admin-guide index
  doc/zh_CN: fix title heading markup in admin-guide cpu-load
  docs: remove the 2.6 "Upgrading I2C Drivers" guide
  docs: Correct the release date of 5.2 stable
  mailmap: Update comments for with format and more detalis
  docs: cdrom: Fix a typo and rst markup
  Doc: admin-guide: use correct legends in kernel-parameters.txt
  Documentation/features: refresh RISC-V arch support files
  documentation: coccinelle: Improve command example for make C={1,2}
  Core-api: Documentation: Replace deprecated :c:func: Usage
  Dev-tools: Documentation: Replace deprecated :c:func: Usage
  Filesystems: Documentation: Replace deprecated :c:func: Usage
  docs: trace: fix a typo

We have three categories locks, not two.
Signed-off-by: Huang Shijie <sjhuang@iluvatar.ai>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200813060220.18199-1-sjhuang@iluvatar.aiSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Pull more s390 updates from Heiko Carstens:

 - Allow s390 debug feature to handle finally more than 256 CPU numbers,
   instead of truncating the most significant bits.

 - Improve THP splitting required by qemu processes by making use of
   walk_page_vma() instead of calling follow_page() for every single
   page within each vma.

 - Add missing ZCRYPT dependency to VFIO_AP to fix potential compile
   problems.

 - Remove not required select CLOCKSOURCE_VALIDATE_LAST_CYCLE again.

 - Set node distance to LOCAL_DISTANCE instead of 0, since e.g. libnuma
   translates a node distance of 0 to "no NUMA support available".

 - Couple of other minor fixes and improvements.

* tag 's390-5.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/numa: move code to arch/s390/kernel
  s390/time: remove select CLOCKSOURCE_VALIDATE_LAST_CYCLE again
  s390/debug: debug feature version 3
  s390/Kconfig: add missing ZCRYPT dependency to VFIO_AP
  s390/numa: set node distance to LOCAL_DISTANCE
  s390/pkey: remove redundant variable initialization
  s390/test_unwind: fix possible memleak in test_unwind()
  s390/gmap: improve THP splitting
  s390/atomic: circumvent gcc 10 build regression

Pull more btrfs updates from David Sterba:
 "One minor update, the rest are fixes that have arrived a bit late for
  the first batch. There are also some recent fixes for bugs that were
  discovered during the merge window and pop up during testing.

  User visible change:

   - show correct subvolume path in /proc/mounts for bind mounts

  Fixes:

   - fix compression messages when remounting with different level or
     compression algorithm

   - tree-log: fix some memory leaks on error handling paths

   - restore I_VERSION on remount

   - fix return values and error code mixups

   - fix umount crash with quotas enabled when removing sysfs files

   - fix trim range on a shrunk device"

* tag 'for-5.9-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: trim: fix underflow in trim length to prevent access beyond device boundary
  btrfs: fix return value mixup in btrfs_get_extent
  btrfs: sysfs: fix NULL pointer dereference at btrfs_sysfs_del_qgroups()
  btrfs: check correct variable after allocation in btrfs_backref_iter_alloc
  btrfs: make sure SB_I_VERSION doesn't get unset by remount
  btrfs: fix memory leaks after failure to lookup checksums during inode logging
  btrfs: don't show full path of bind mounts in subvol=
  btrfs: fix messages after changing compression level by remount
  btrfs: only search for left_info if there is no right_info in try_merge_free_space
  btrfs: inode: fix NULL pointer dereference if inode doesn't need compression

Pull xfs fixes from Darrick Wong:
 "Two small fixes that have come in during the past week:

   - Fix duplicated words in comments

   - Fix an ubsan complaint about null pointer arithmetic"

* tag 'xfs-5.9-merge-8' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: Fix UBSAN null-ptr-deref in xfs_sysfs_init
  xfs: delete duplicated words + other fixes

Pull exfat updates from Namjae Jeon:

 - don't clear MediaFailure and VolumeDirty bit in volume flags if these
   were already set before mounting

 - write multiple dirty buffers at once in sync mode

 - remove unneeded EXFAT_SB_DIRTY bit set

* tag 'exfat-for-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat:
  exfat: retain 'VolumeFlags' properly
  exfat: optimize exfat_zeroed_cluster()
  exfat: add error check when updating dir-entries
  exfat: write multiple sectors at once
  exfat: remove EXFAT_SB_DIRTY flag

Commit 3e38e0aa ("mm: memcg: charge memcg percpu memory to the
parent cgroup") adds memory tracking to the memcg kernel structures
themselves to make cgroups liable for the memory they are consuming
through the allocation of child groups (which can be significant).

This code is a bit awkward as it's spread out through several functions:
The outermost function does memalloc_use_memcg(parent) to set up
current->active_memcg, which designates which cgroup to charge, and the
inner functions pass GFP_ACCOUNT to request charging for specific
allocations.  To make sure this dependency is satisfied at all times -
to make sure we don't randomly charge whoever is calling the functions -
the inner functions warn on !current->active_memcg.

However, this triggers a false warning when the root memcg itself is
allocated.  No parent exists in this case, and so current->active_memcg
is rightfully NULL.  It's a false positive, not indicative of a bug.

Delete the warnings for now, we can revisit this later.

Fixes: 3e38e0aa ("mm: memcg: charge memcg percpu memory to the parent cgroup")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>