It's possible to hit the WARN_ON_ONCE(page_mapped(page)) in
remove_stable_node() when it races with __mmput() and squeezes in
between ksm_exit() and exit_mmap().

  WARNING: CPU: 0 PID: 3295 at mm/ksm.c:888 remove_stable_node+0x10c/0x150

  Call Trace:
   remove_all_stable_nodes+0x12b/0x330
   run_store+0x4ef/0x7b0
   kernfs_fop_write+0x200/0x420
   vfs_write+0x154/0x450
   ksys_write+0xf9/0x1d0
   do_syscall_64+0x99/0x510
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Remove the warning as there is nothing scary going on.

Link: http://lkml.kernel.org/r/20191119131850.5675-1-aryabinin@virtuozzo.com
Fixes: cbf86cfe ("ksm: remove old stable nodes more thoroughly")
Signed-off-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: NHugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Let's limit shrinking to !ZONE_DEVICE so we can fix the current code.
We should never try to touch the memmap of offline sections where we
could have uninitialized memmaps and could trigger BUGs when calling
page_to_nid() on poisoned pages.

There is no reliable way to distinguish an uninitialized memmap from an
initialized memmap that belongs to ZONE_DEVICE, as we don't have
anything like SECTION_IS_ONLINE we can use similar to
pfn_to_online_section() for !ZONE_DEVICE memory.

E.g., set_zone_contiguous() similarly relies on pfn_to_online_section()
and will therefore never set a ZONE_DEVICE zone consecutive.  Stopping
to shrink the ZONE_DEVICE therefore results in no observable changes,
besides /proc/zoneinfo indicating different boundaries - something we
can totally live with.

Before commit d0dc12e8 ("mm/memory_hotplug: optimize memory
hotplug"), the memmap was initialized with 0 and the node with the right
value.  So the zone might be wrong but not garbage.  After that commit,
both the zone and the node will be garbage when touching uninitialized
memmaps.

Toshiki reported a BUG (race between delayed initialization of
ZONE_DEVICE memmaps without holding the memory hotplug lock and
concurrent zone shrinking).

  https://lkml.org/lkml/2019/11/14/1040

"Iteration of create and destroy namespace causes the panic as below:

      kernel BUG at mm/page_alloc.c:535!
      CPU: 7 PID: 2766 Comm: ndctl Not tainted 5.4.0-rc4 #6
      Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.0-0-g63451fca13-prebuilt.qemu-project.org 04/01/2014
      RIP: 0010:set_pfnblock_flags_mask+0x95/0xf0
      Call Trace:
       memmap_init_zone_device+0x165/0x17c
       memremap_pages+0x4c1/0x540
       devm_memremap_pages+0x1d/0x60
       pmem_attach_disk+0x16b/0x600 [nd_pmem]
       nvdimm_bus_probe+0x69/0x1c0
       really_probe+0x1c2/0x3e0
       driver_probe_device+0xb4/0x100
       device_driver_attach+0x4f/0x60
       bind_store+0xc9/0x110
       kernfs_fop_write+0x116/0x190
       vfs_write+0xa5/0x1a0
       ksys_write+0x59/0xd0
       do_syscall_64+0x5b/0x180
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

  While creating a namespace and initializing memmap, if you destroy the
  namespace and shrink the zone, it will initialize the memmap outside
  the zone and trigger VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page),
  pfn), page) in set_pfnblock_flags_mask()."

This BUG is also mitigated by this commit, where we for now stop to
shrink the ZONE_DEVICE zone until we can do it in a safe and clean way.

Link: http://lkml.kernel.org/r/20191006085646.5768-5-david@redhat.com
Fixes: f1dd2cd1 ("mm, memory_hotplug: do not associate hotadded memory to zones until online")	[visible after d0dc12e8]
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Reported-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reported-by: NToshiki Fukasawa <t-fukasawa@vx.jp.nec.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Damian Tometzki <damian.tometzki@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Halil Pasic <pasic@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jun Yao <yaojun8558363@gmail.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Pankaj Gupta <pagupta@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Rich Felker <dalias@libc.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>	[4.13+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This reverts commit 56e94ea1.

Commit 56e94ea1 ("fs: ocfs2: fix possible null-pointer dereferences
in ocfs2_xa_prepare_entry()") introduces a regression that fail to
create directory with mount option user_xattr and acl.  Actually the
reported NULL pointer dereference case can be correctly handled by
loc->xl_ops->xlo_add_entry(), so revert it.

Link: http://lkml.kernel.org/r/1573624916-83825-1-git-send-email-joseph.qi@linux.alibaba.com
Fixes: 56e94ea1 ("fs: ocfs2: fix possible null-pointer dereferences in ocfs2_xa_prepare_entry()")
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reported-by: NThomas Voegtle <tv@lio96.de>
Acked-by: NChangwei Ge <gechangwei@live.cn>
Cc: Jia-Ju Bai <baijiaju1990@gmail.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull arm64 fix from Will Deacon:
 "Ensure PAN is re-enabled following user fault in uaccess routines.

  After I thought we were done for 5.4, we had a report this week of a
  nasty issue that has been shown to leak data between different user
  address spaces thanks to corruption of entries in the TLB. In
  hindsight, we should have spotted this in review when the PAN code was
  merged back in v4.3, but hindsight is 20/20 and I'm trying not to beat
  myself up too much about it despite being fairly miserable.

  Anyway, the fix is "obvious" but the actual failure is more more
  subtle, and is described in the commit message. I've included a fairly
  mechanical follow-up patch here as well, which moves this checking out
  into the C wrappers which is what we do for {get,put}_user() already
  and allows us to remove these bloody assembly macros entirely. The
  patches have passed kernelci [1] [2] [3] and CKI [4] tests over night,
  as well as some targetted testing [5] for this particular issue.

  The first patch is tagged for stable and should be applied to 4.14,
  4.19 and 5.3. I have separate backports for 4.4 and 4.9, which I'll
  send out once this has landed in your tree (although the original
  patch applies cleanly, it won't build for those two trees).

  Thanks to Pavel Tatashin for reporting this and Mark Rutland for
  helping to diagnose the issue and review/test the solution"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: uaccess: Remove uaccess_*_not_uao asm macros
  arm64: uaccess: Ensure PAN is re-enabled after unhandled uaccess fault

Pull block fix from Jens Axboe:
 "Just a single fix for an issue in nbd introduced in this cycle"

* tag 'for-linus-20191121' of git://git.kernel.dk/linux-block:
  nbd:fix memory leak in nbd_get_socket()

Pull GPIO fixes from Linus Walleij:
 "A last set of small fixes for GPIO, this cycle was quite busy.

   - Fix debounce delays on the MAX77620 GPIO expander

   - Use the correct unit for debounce times on the BD70528 GPIO expander

   - Get proper deps for parallel builds of the GPIO tools

   - Add a specific ACPI quirk for the Terra Pad 1061"

* tag 'gpio-v5.4-5' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  gpiolib: acpi: Add Terra Pad 1061 to the run_edge_events_on_boot_blacklist
  tools: gpio: Correctly add make dependencies for gpio_utils
  gpio: bd70528: Use correct unit for debounce times
  gpio: max77620: Fixup debounce delays

Pull pidfd fixlet from Christian Brauner:
 "This contains a simple fix for the pidfd poll method. In the original
  patchset pidfd_poll() was made to return an unsigned int. However, the
  poll method is defined to return a __poll_t. While the unsigned int is
  not a huge deal it's just nicer to return a __poll_t.

  I've decided to send it right before the 5.4 release mainly so that
  stable doesn't need to backport it to both 5.4 and 5.3"

* tag 'for-linus-2019-11-21' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  fork: fix pidfd_poll()'s return type

It is safer and simpler to drop the uaccess assembly macros in favour of
inline C functions. Although this bloats the Image size slightly, it
aligns our user copy routines with '{get,put}_user()' and generally
makes the code a lot easier to reason about.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: NMark Rutland <mark.rutland@arm.com>
Tested-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NPavel Tatashin <pasha.tatashin@soleen.com>
[will: tweaked commit message and changed temporary variable names]
Signed-off-by: NWill Deacon <will@kernel.org>

A number of our uaccess routines ('__arch_clear_user()' and
'__arch_copy_{in,from,to}_user()') fail to re-enable PAN if they
encounter an unhandled fault whilst accessing userspace.

For CPUs implementing both hardware PAN and UAO, this bug has no effect
when both extensions are in use by the kernel.

For CPUs implementing hardware PAN but not UAO, this means that a kernel
using hardware PAN may execute portions of code with PAN inadvertently
disabled, opening us up to potential security vulnerabilities that rely
on userspace access from within the kernel which would usually be
prevented by this mechanism. In other words, parts of the kernel run the
same way as they would on a CPU without PAN implemented/emulated at all.

For CPUs not implementing hardware PAN and instead relying on software
emulation via 'CONFIG_ARM64_SW_TTBR0_PAN=y', the impact is unfortunately
much worse. Calling 'schedule()' with software PAN disabled means that
the next task will execute in the kernel using the page-table and ASID
of the previous process even after 'switch_mm()', since the actual
hardware switch is deferred until return to userspace. At this point, or
if there is a intermediate call to 'uaccess_enable()', the page-table
and ASID of the new process are installed. Sadly, due to the changes
introduced by KPTI, this is not an atomic operation and there is a very
small window (two instructions) where the CPU is configured with the
page-table of the old task and the ASID of the new task; a speculative
access in this state is disastrous because it would corrupt the TLB
entries for the new task with mappings from the previous address space.

As Pavel explains:

  | I was able to reproduce memory corruption problem on Broadcom's SoC
  | ARMv8-A like this:
  |
  | Enable software perf-events with PERF_SAMPLE_CALLCHAIN so userland's
  | stack is accessed and copied.
  |
  | The test program performed the following on every CPU and forking
  | many processes:
  |
  |	unsigned long *map = mmap(NULL, PAGE_SIZE, PROT_READ|PROT_WRITE,
  |				  MAP_SHARED | MAP_ANONYMOUS, -1, 0);
  |	map[0] = getpid();
  |	sched_yield();
  |	if (map[0] != getpid()) {
  |		fprintf(stderr, "Corruption detected!");
  |	}
  |	munmap(map, PAGE_SIZE);
  |
  | From time to time I was getting map[0] to contain pid for a
  | different process.

Ensure that PAN is re-enabled when returning after an unhandled user
fault from our uaccess routines.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: NMark Rutland <mark.rutland@arm.com>
Tested-by: NMark Rutland <mark.rutland@arm.com>
Cc: <stable@vger.kernel.org>
Fixes: 338d4f49 ("arm64: kernel: Add support for Privileged Access Never")
Signed-off-by: NPavel Tatashin <pasha.tatashin@soleen.com>
[will: rewrote commit message]
Signed-off-by: NWill Deacon <will@kernel.org>

pidfd_poll() is defined as returning 'unsigned int' but the
.poll method is declared as returning '__poll_t', a bitwise type.

Fix this by using the proper return type and using the EPOLL
constants instead of the POLL ones, as required for __poll_t.

Fixes: b53b0b9d ("pidfd: add polling support")
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: stable@vger.kernel.org # 5.3
Signed-off-by: NLuc Van Oostenryck <luc.vanoostenryck@gmail.com>
Reviewed-by: NChristian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20191120003320.31138-1-luc.vanoostenryck@gmail.comSigned-off-by: NChristian Brauner <christian.brauner@ubuntu.com>

In afs_wait_for_call_to_complete(), rather than immediately aborting an
operation if a signal occurs, the code attempts to wait for it to
complete, using a schedule timeout of 2*RTT (or min 2 jiffies) and a
check that we're still receiving relevant packets from the server before
we consider aborting the call.  We may even ping the server to check on
the status of the call.

However, there's a missing timeout reset in the event that we do
actually get a packet to process, such that if we then get a couple of
short stalls, we then time out when progress is actually being made.

Fix this by resetting the timeout any time we get something to process.
If it's the failure of the call then the call state will get changed and
we'll exit the loop shortly thereafter.

A symptom of this is data fetches and stores failing with EINTR when
they really shouldn't.

Fixes: bc5e3a54 ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NMarc Dionne <marc.dionne@auristor.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 1d463956 ("mdio_bus: Fix PTR_ERR applied after initialization
to constant") accidentally changed a check from -ENOTSUPP to -ENOSYS,
causing failures if reset controller support is not enabled.  E.g. on
r7s72100/rskrza1:

    sh-eth e8203000.ethernet: MDIO init failed: -524
    sh-eth: probe of e8203000.ethernet failed with error -524

Seen on r8a7740/armadillo, r7s72100/rskrza1, and r7s9210/rza2mevb.

Fixes: 1d463956 ("mdio_bus: Fix PTR_ERR applied after initialization to constant")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Cc: YueHaibing <yuehaibing@huawei.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Before returning NULL, put the sock first.

Cc: stable@vger.kernel.org
Fixes: cf1b2326 ("nbd: verify socket is supported during setup")
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NSun Ke <sunke32@huawei.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Pull iommu fixes from Joerg Roedel:

 - Fix for Intel IOMMU to correct invalidation commands when in SVA
   mode.

 - Update MAINTAINERS entry for Intel IOMMU

* tag 'iommu-fixes-v5.4-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/vt-d: Fix QI_DEV_IOTLB_PFSID and QI_DEV_EIOTLB_PFSID macros
  MAINTAINERS: Update for INTEL IOMMU (VT-d) entry

Pull misc scheduler fixes from Ingo Molnar:

 - Fix potential deadlock under CONFIG_DEBUG_OBJECTS=y

 - PELT metrics update ordering fix

 - uclamp logic fix

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/uclamp: Fix incorrect condition
  sched/pelt: Fix update of blocked PELT ordering
  sched/core: Avoid spurious lock dependencies

Pull i2c fixes from Wolfram Sang:
 "An I2C core fix to prevent a use-after-free in a rare error path,
  and an I2C ACPI addition to work around broken HW/firmware related
  to touchscreens"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: core: fix use after free in of_i2c_notify
  i2c: acpi: Force bus speed to 400KHz if a Silead touchscreen is present

Pull crypto fix from Herbert Xu:
 "This reverts a number of changes to the khwrng thread which feeds the
  kernel random number pool from hwrng drivers. They were trying to fix
  issues with suspend-and-resume but ended up causing regressions"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  Revert "hwrng: core - Freeze khwrng thread during suspend"

This reverts commit 03a3bb7a ("hwrng: core - Freeze khwrng
thread during suspend"), ff296293 ("random: Support freezable
kthreads in add_hwgenerator_randomness()") and 59b56948 ("random:
Use wait_event_freezable() in add_hwgenerator_randomness()").

These patches introduced regressions and we need more time to
get them ready for mainline.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Pull x86 fixes from Ingo Molnar:
 "Two fixes: disable unreliable HPET on Intel Coffe Lake platforms, and
  fix a lockdep splat in the resctrl code"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/resctrl: Fix potential lockdep warning
  x86/quirks: Disable HPET on Intel Coffe Lake platforms

Pull timer fix from Ingo Molnar:
 "Fix integer truncation bug in __do_adjtimex()"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ntp/y2038: Remove incorrect time_t truncation

Pull perf fixes from Ingo Molnar:
 "Misc fixes: a handful of AUX event handling related fixes, a Sparse
  fix and two ABI fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Fix missing static inline on perf_cgroup_switch()
  perf/core: Consistently fail fork on allocation failures
  perf/aux: Disallow aux_output for kernel events
  perf/core: Reattach a misplaced comment
  perf/aux: Fix the aux_output group inheritance fix
  perf/core: Disallow uncore-cgroup events

Pull networking fixes from David Miller:

 1) Fix memory leak in xfrm_state code, from Steffen Klassert.

 2) Fix races between devlink reload operations and device
    setup/cleanup, from Jiri Pirko.

 3) Null deref in NFC code, from Stephan Gerhold.

 4) Refcount fixes in SMC, from Ursula Braun.

 5) Memory leak in slcan open error paths, from Jouni Hogander.

 6) Fix ETS bandwidth validation in hns3, from Yonglong Liu.

 7) Info leak on short USB request answers in ax88172a driver, from
    Oliver Neukum.

 8) Release mem region properly in ep93xx_eth, from Chuhong Yuan.

 9) PTP config timestamp flags validation, from Richard Cochran.

10) Dangling pointers after SKB data realloc in seg6, from Andrea Mayer.

11) Missing free_netdev() in gemini driver, from Chuhong Yuan.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (56 commits)
  ipmr: Fix skb headroom in ipmr_get_route().
  net: hns3: cleanup of stray struct hns3_link_mode_mapping
  net/smc: fix fastopen for non-blocking connect()
  rds: ib: update WR sizes when bringing up connection
  net: gemini: add missed free_netdev
  net: dsa: tag_8021q: Fix dsa_8021q_restore_pvid for an absent pvid
  seg6: fix skb transport_header after decap_and_validate()
  seg6: fix srh pointer in get_srh()
  net: stmmac: Use the correct style for SPDX License Identifier
  octeontx2-af: Use the correct style for SPDX License Identifier
  ptp: Extend the test program to check the external time stamp flags.
  mlx5: Reject requests to enable time stamping on both edges.
  igb: Reject requests that fail to enable time stamping on both edges.
  dp83640: Reject requests to enable time stamping on both edges.
  mv88e6xxx: Reject requests to enable time stamping on both edges.
  ptp: Introduce strict checking of external time stamp options.
  renesas: reject unsupported external timestamp flags
  mlx5: reject unsupported external timestamp flags
  igb: reject unsupported external timestamp flags
  dp83640: reject unsupported external timestamp flags
  ...

In route.c, inet_rtm_getroute_build_skb() creates an skb with no
headroom. This skb is then used by inet_rtm_getroute() which may pass
it to rt_fill_info() and, from there, to ipmr_get_route(). The later
might try to reuse this skb by cloning it and prepending an IPv4
header. But since the original skb has no headroom, skb_push() triggers
skb_under_panic():

skbuff: skb_under_panic: text:00000000ca46ad8a len:80 put:20 head:00000000cd28494e data:000000009366fd6b tail:0x3c end:0xec0 dev:veth0
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:108!
invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 6 PID: 587 Comm: ip Not tainted 5.4.0-rc6+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
RIP: 0010:skb_panic+0xbf/0xd0
Code: 41 a2 ff 8b 4b 70 4c 8b 4d d0 48 c7 c7 20 76 f5 8b 44 8b 45 bc 48 8b 55 c0 48 8b 75 c8 41 54 41 57 41 56 41 55 e8 75 dc 7a ff <0f> 0b 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00
RSP: 0018:ffff888059ddf0b0 EFLAGS: 00010286
RAX: 0000000000000086 RBX: ffff888060a315c0 RCX: ffffffff8abe4822
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88806c9a79cc
RBP: ffff888059ddf118 R08: ffffed100d9361b1 R09: ffffed100d9361b0
R10: ffff88805c68aee3 R11: ffffed100d9361b1 R12: ffff88805d218000
R13: ffff88805c689fec R14: 000000000000003c R15: 0000000000000ec0
FS:  00007f6af184b700(0000) GS:ffff88806c980000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc8204a000 CR3: 0000000057b40006 CR4: 0000000000360ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 skb_push+0x7e/0x80
 ipmr_get_route+0x459/0x6fa
 rt_fill_info+0x692/0x9f0
 inet_rtm_getroute+0xd26/0xf20
 rtnetlink_rcv_msg+0x45d/0x630
 netlink_rcv_skb+0x1a5/0x220
 rtnetlink_rcv+0x15/0x20
 netlink_unicast+0x305/0x3a0
 netlink_sendmsg+0x575/0x730
 sock_sendmsg+0xb5/0xc0
 ___sys_sendmsg+0x497/0x4f0
 __sys_sendmsg+0xcb/0x150
 __x64_sys_sendmsg+0x48/0x50
 do_syscall_64+0xd2/0xac0
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Actually the original skb used to have enough headroom, but the
reserve_skb() call was lost with the introduction of
inet_rtm_getroute_build_skb() by commit 404eb77e ("ipv4: support
sport, dport and ip_proto in RTM_GETROUTE").

We could reserve some headroom again in inet_rtm_getroute_build_skb(),
but this function shouldn't be responsible for handling the special
case of ipmr_get_route(). Let's handle that directly in
ipmr_get_route() by calling skb_realloc_headroom() instead of
skb_clone().

Fixes: 404eb77e ("ipv4: support sport, dport and ip_proto in RTM_GETROUTE")
Signed-off-by: NGuillaume Nault <gnault@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch cleans-up the stray left over code. It has no
functionality impact.
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

FASTOPEN does not work with SMC-sockets. Since SMC allows fallback to
TCP native during connection start, the FASTOPEN setsockopts trigger
this fallback, if the SMC-socket is still in state SMC_INIT.
But if a FASTOPEN setsockopt is called after a non-blocking connect(),
this is broken, and fallback does not make sense.
This change complements
commit cd206360 ("net/smc: avoid fallback in case of non-blocking connect")
and fixes the syzbot reported problem "WARNING in smc_unhash_sk".

Reported-by: syzbot+8488cc4cf1c9e09b8b86@syzkaller.appspotmail.com
Fixes: e1bbdd57 ("net/smc: reduce sock_put() for fallback sockets")
Signed-off-by: NUrsula Braun <ubraun@linux.ibm.com>
Signed-off-by: NKarsten Graul <kgraul@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently WR sizes are updated from rds_ib_sysctl_max_send_wr and
rds_ib_sysctl_max_recv_wr when a connection is shut down. As a result,
a connection being down while rds_ib_sysctl_max_send_wr or
rds_ib_sysctl_max_recv_wr are updated, will not update the sizes when
it comes back up.

Move resizing of WRs to rds_ib_setup_qp so that connections will be setup
with the most current WR sizes.
Signed-off-by: NDag Moxnes <dag.moxnes@oracle.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This driver forgets to free allocated netdev in remove like
what is done in probe failure.
Add the free to fix it.
Signed-off-by: NChuhong Yuan <hslester96@gmail.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This sequence of operations:
ip link set dev br0 type bridge vlan_filtering 1
bridge vlan del dev swp2 vid 1
ip link set dev br0 type bridge vlan_filtering 1
ip link set dev br0 type bridge vlan_filtering 0

apparently fails with the message:

[   31.305716] sja1105 spi0.1: Reset switch and programmed static config. Reason: VLAN filtering
[   31.322161] sja1105 spi0.1: Couldn't determine PVID attributes (pvid 0)
[   31.328939] sja1105 spi0.1: Failed to setup VLAN tagging for port 1: -2
[   31.335599] ------------[ cut here ]------------
[   31.340215] WARNING: CPU: 1 PID: 194 at net/switchdev/switchdev.c:157 switchdev_port_attr_set_now+0x9c/0xa4
[   31.349981] br0: Commit of attribute (id=6) failed.
[   31.354890] Modules linked in:
[   31.357942] CPU: 1 PID: 194 Comm: ip Not tainted 5.4.0-rc6-01792-gf4f632e07665-dirty #2062
[   31.366167] Hardware name: Freescale LS1021A
[   31.370437] [<c03144dc>] (unwind_backtrace) from [<c030e184>] (show_stack+0x10/0x14)
[   31.378153] [<c030e184>] (show_stack) from [<c11d1c1c>] (dump_stack+0xe0/0x10c)
[   31.385437] [<c11d1c1c>] (dump_stack) from [<c034c730>] (__warn+0xf4/0x10c)
[   31.392373] [<c034c730>] (__warn) from [<c034c7bc>] (warn_slowpath_fmt+0x74/0xb8)
[   31.399827] [<c034c7bc>] (warn_slowpath_fmt) from [<c11ca204>] (switchdev_port_attr_set_now+0x9c/0xa4)
[   31.409097] [<c11ca204>] (switchdev_port_attr_set_now) from [<c117036c>] (__br_vlan_filter_toggle+0x6c/0x118)
[   31.418971] [<c117036c>] (__br_vlan_filter_toggle) from [<c115d010>] (br_changelink+0xf8/0x518)
[   31.427637] [<c115d010>] (br_changelink) from [<c0f8e9ec>] (__rtnl_newlink+0x3f4/0x76c)
[   31.435613] [<c0f8e9ec>] (__rtnl_newlink) from [<c0f8eda8>] (rtnl_newlink+0x44/0x60)
[   31.443329] [<c0f8eda8>] (rtnl_newlink) from [<c0f89f20>] (rtnetlink_rcv_msg+0x2cc/0x51c)
[   31.451477] [<c0f89f20>] (rtnetlink_rcv_msg) from [<c1008df8>] (netlink_rcv_skb+0xb8/0x110)
[   31.459796] [<c1008df8>] (netlink_rcv_skb) from [<c1008648>] (netlink_unicast+0x17c/0x1f8)
[   31.468026] [<c1008648>] (netlink_unicast) from [<c1008980>] (netlink_sendmsg+0x2bc/0x3b4)
[   31.476261] [<c1008980>] (netlink_sendmsg) from [<c0f43858>] (___sys_sendmsg+0x230/0x250)
[   31.484408] [<c0f43858>] (___sys_sendmsg) from [<c0f44c84>] (__sys_sendmsg+0x50/0x8c)
[   31.492209] [<c0f44c84>] (__sys_sendmsg) from [<c0301000>] (ret_fast_syscall+0x0/0x28)
[   31.500090] Exception stack(0xedf47fa8 to 0xedf47ff0)
[   31.505122] 7fa0:                   00000002 b6f2e060 00000003 beabd6a4 00000000 00000000
[   31.513265] 7fc0: 00000002 b6f2e060 5d6e3213 00000128 00000000 00000001 00000006 000619c4
[   31.521405] 7fe0: 00086078 beabd658 0005edbc b6e7ce68

The reason is the implementation of br_get_pvid:

static inline u16 br_get_pvid(const struct net_bridge_vlan_group *vg)
{
	if (!vg)
		return 0;

	smp_rmb();
	return vg->pvid;
}

Since VID 0 is an invalid pvid from the bridge's point of view, let's
add this check in dsa_8021q_restore_pvid to avoid restoring a pvid that
doesn't really exist.

Fixes: 5f33183b ("net: dsa: tag_8021q: Restore bridge VLANs when enabling vlan_filtering")
Signed-off-by: NVladimir Oltean <olteanv@gmail.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Andrea Mayer says:

====================
seg6: fixes to Segment Routing in IPv6

This patchset is divided in 2 patches and it introduces some fixes
to Segment Routing in IPv6, which are:

- in function get_srh() fix the srh pointer after calling
  pskb_may_pull();

- fix the skb->transport_header after calling decap_and_validate()
  function;

Any comments on the patchset are welcome.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

in the receive path (more precisely in ip6_rcv_core()) the
skb->transport_header is set to skb->network_header + sizeof(*hdr). As a
consequence, after routing operations, destination input expects to find
skb->transport_header correctly set to the next protocol (or extension
header) that follows the network protocol. However, decap behaviors (DX*,
DT*) remove the outer IPv6 and SRH extension and do not set again the
skb->transport_header pointer correctly. For this reason, the patch sets
the skb->transport_header to the skb->network_header + sizeof(hdr) in each
DX* and DT* behavior.
Signed-off-by: NAndrea Mayer <andrea.mayer@uniroma2.it>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

pskb_may_pull may change pointers in header. For this reason, it is
mandatory to reload any pointer that points into skb header.
Signed-off-by: NAndrea Mayer <andrea.mayer@uniroma2.it>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch corrects the SPDX License Identifier style in
header files related to STMicroelectronics based Multi-Gigabit
Ethernet driver. For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used).

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.
Suggested-by: NJoe Perches <joe@perches.com>
Signed-off-by: NNishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch corrects the SPDX License Identifier style in
header files related to Marvell OcteonTX2 network devices.
It uses an expilict block comment for the SPDX License
Identifier.

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.
Suggested-by: NJoe Perches <joe@perches.com>
Signed-off-by: NNishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Merge misc fixes from Andrew Morton:
 "11 fixes"

MM fixes and one xz decompressor fix.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm/debug.c: PageAnon() is true for PageKsm() pages
  mm/debug.c: __dump_page() prints an extra line
  mm/page_io.c: do not free shared swap slots
  mm/memory_hotplug: fix try_offline_node()
  mm,thp: recheck each page before collapsing file THP
  mm: slub: really fix slab walking for init_on_free
  mm: hugetlb: switch to css_tryget() in hugetlb_cgroup_charge_cgroup()
  mm: memcg: switch to css_tryget() in get_mem_cgroup_from_mm()
  lib/xz: fix XZ_DYNALLOC to avoid useless memory reallocations
  mm: fix trying to reclaim unevictable lru page when calling madvise_pageout
  mm: mempolicy: fix the wrong return value and potential pages leak of mbind

Pull more input fixes from Dmitry Torokhov:
 "A couple of fixes in driver teardown paths and another ID for
  Synaptics RMI mode"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: synaptics - enable RMI mode for X1 Extreme 2nd Generation
  Input: synaptics-rmi4 - destroy F54 poller workqueue when removing
  Input: ff-memless - kill timer in destroy()

PageAnon() and PageKsm() use the low two bits of the page->mapping
pointer to indicate the page type.  PageAnon() only checks the LSB while
PageKsm() checks the least significant 2 bits are equal to 3.

Therefore, PageAnon() is true for KSM pages.  __dump_page() incorrectly
will never print "ksm" because it checks PageAnon() first.  Fix this by
checking PageKsm() first.

Link: http://lkml.kernel.org/r/20191113000651.20677-1-rcampbell@nvidia.com
Fixes: 1c6fb1d8 ("mm: print more information about mapping in __dump_page")
Signed-off-by: NRalph Campbell <rcampbell@nvidia.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When dumping struct page information, __dump_page() prints the page type
with a trailing blank followed by the page flags on a separate line:

  anon
  flags: 0x100000000090034(uptodate|lru|active|head|swapbacked)

It looks like the intent was to use pr_cont() for printing "flags:" but
pr_cont() usage is discouraged so fix this by extending the format to
include the flags into a single line:

  anon flags: 0x100000000090034(uptodate|lru|active|head|swapbacked)

If the page is file backed, the name might be long so use two lines:

  shmem_aops name:"dev/zero"
  flags: 0x10000000008000c(uptodate|dirty|swapbacked)

Eliminate pr_conf() usage as well for appending compound_mapcount.

Link: http://lkml.kernel.org/r/20191112012608.16926-1-rcampbell@nvidia.comSigned-off-by: NRalph Campbell <rcampbell@nvidia.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The following race is observed due to which a processes faulting on a
swap entry, finds the page neither in swapcache nor swap.  This causes
zram to give a zero filled page that gets mapped to the process,
resulting in a user space crash later.

Consider parent and child processes Pa and Pb sharing the same swap slot
with swap_count 2.  Swap is on zram with SWP_SYNCHRONOUS_IO set.
Virtual address 'VA' of Pa and Pb points to the shared swap entry.

Pa                                       Pb

fault on VA                              fault on VA
do_swap_page                             do_swap_page
lookup_swap_cache fails                  lookup_swap_cache fails
                                         Pb scheduled out
swapin_readahead (deletes zram entry)
swap_free (makes swap_count 1)
                                         Pb scheduled in
                                         swap_readpage (swap_count == 1)
                                         Takes SWP_SYNCHRONOUS_IO path
                                         zram enrty absent
                                         zram gives a zero filled page

Fix this by making sure that swap slot is freed only when swap count
drops down to one.

Link: http://lkml.kernel.org/r/1571743294-14285-1-git-send-email-vinmenon@codeaurora.org
Fixes: aa8d22a1 ("mm: swap: SWP_SYNCHRONOUS_IO: skip swapcache only if swapped page has no other reference")
Signed-off-by: NVinayak Menon <vinmenon@codeaurora.org>
Suggested-by: NMinchan Kim <minchan@google.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

try_offline_node() is pretty much broken right now:

 - The node span is updated when onlining memory, not when adding it. We
   ignore memory that was mever onlined. Bad.

 - We touch possible garbage memmaps. The pfn_to_nid(pfn) can easily
   trigger a kernel panic. Bad for memory that is offline but also bad
   for subsection hotadd with ZONE_DEVICE, whereby the memmap of the
   first PFN of a section might contain garbage.

 - Sections belonging to mixed nodes are not properly considered.

As memory blocks might belong to multiple nodes, we would have to walk
all pageblocks (or at least subsections) within present sections.
However, we don't have a way to identify whether a memmap that is not
online was initialized (relevant for ZONE_DEVICE).  This makes things
more complicated.

Luckily, we can piggy pack on the node span and the nid stored in memory
blocks.  Currently, the node span is grown when calling
move_pfn_range_to_zone() - e.g., when onlining memory, and shrunk when
removing memory, before calling try_offline_node().  Sysfs links are
created via link_mem_sections(), e.g., during boot or when adding
memory.

If the node still spans memory or if any memory block belongs to the
nid, we don't set the node offline.  As memory blocks that span multiple
nodes cannot get offlined, the nid stored in memory blocks is reliable
enough (for such online memory blocks, the node still spans the memory).

Introduce for_each_memory_block() to efficiently walk all memory blocks.

Note: We will soon stop shrinking the ZONE_DEVICE zone and the node span
when removing ZONE_DEVICE memory to fix similar issues (access of
garbage memmaps) - until we have a reliable way to identify whether
these memmaps were properly initialized.  This implies later, that once
a node had ZONE_DEVICE memory, we won't be able to set a node offline -
which should be acceptable.

Since commit f1dd2cd1 ("mm, memory_hotplug: do not associate
hotadded memory to zones until online") memory that is added is not
assoziated with a zone/node (memmap not initialized).  The introducing
commit 60a5a19e ("memory-hotplug: remove sysfs file of node")
already missed that we could have multiple nodes for a section and that
the zone/node span is updated when onlining pages, not when adding them.

I tested this by hotplugging two DIMMs to a memory-less and cpu-less
NUMA node.  The node is properly onlined when adding the DIMMs.  When
removing the DIMMs, the node is properly offlined.

Masayoshi Mizuma reported:

: Without this patch, memory hotplug fails as panic:
:
:  BUG: kernel NULL pointer dereference, address: 0000000000000000
:  ...
:  Call Trace:
:   remove_memory_block_devices+0x81/0xc0
:   try_remove_memory+0xb4/0x130
:   __remove_memory+0xa/0x20
:   acpi_memory_device_remove+0x84/0x100
:   acpi_bus_trim+0x57/0x90
:   acpi_bus_trim+0x2e/0x90
:   acpi_device_hotplug+0x2b2/0x4d0
:   acpi_hotplug_work_fn+0x1a/0x30
:   process_one_work+0x171/0x380
:   worker_thread+0x49/0x3f0
:   kthread+0xf8/0x130
:   ret_from_fork+0x35/0x40

[david@redhat.com: v3]
  Link: http://lkml.kernel.org/r/20191102120221.7553-1-david@redhat.com
Link: http://lkml.kernel.org/r/20191028105458.28320-1-david@redhat.com
Fixes: 60a5a19e ("memory-hotplug: remove sysfs file of node")
Fixes: f1dd2cd1 ("mm, memory_hotplug: do not associate hotadded memory to zones until online") # visiable after d0dc12e8Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Tested-by: NMasayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Nayna Jain <nayna@linux.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>