Change the parisc vmlinuz boot code to include and process the real
compressed vmlinux.gz ELF file instead of a compressed memory dump.
This brings parisc in sync on how it's done on x86_64.

The benefit of this change is that, e.g. for debugging purposes, one can
then extract the vmlinux file out of the vmlinuz which was booted which
wasn't possible before. This can be archieved with the existing
scripts/extract-vmlinux script, which just needs a small tweak to prefer
to extract a compressed file before trying the existing given binary.

The downside of this approach is that due to the extra round of
decompression/ELF processing we need more physical memory installed to
be able to boot a kernel.
Signed-off-by: Helge Deller <deller@gmx.de>

As on x86-64 and other architectures, the boot kernel on parisc (vmlinuz
and bzImage) contains a full compressed copy of the final kernel
executable (vmlinux.bin.gz), which one should be able to extract with
the extract-vmlinux script.

But on parisc extracting the kernel with extract-vmlinux fails.
Currently the script first checks if the given file is an ELF file
(which is true on parisc) and if so returns it.  Thus on parisc we
unexpectedly get back the vmlinuz boot file instead of the uncompressed
vmlinux image.

This patch fixes this issue by reverting the logic. It now first tries
to find a compression signature in the given file and if that fails it
checks the file itself as fallback.
Signed-off-by: Helge Deller <deller@gmx.de>

Helge noticed that the address of the os_hpmc handler was not being
correctly calculated in the hpmc macro.  As a result, PDCE_CHECK would
fail to call os_hpmc:

<Cpu2> e800009802e00000  0000000000000000  CC_ERR_CHECK_HPMC
<Cpu2> 37000f7302e00000  8040004000000000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu2> f600105e02e00000  fffffff0f0c00000  CC_MC_HPMC_MONARCH_SELECTED
<Cpu2> 140003b202e00000  000000000000000b  CC_ERR_HPMC_STATE_ENTRY
<Cpu2> 5600100b02e00000  00000000000001a0  CC_MC_OS_HPMC_LEN_ERR
<Cpu2> 5600106402e00000  fffffff0f0438e70  CC_MC_BR_TO_OS_HPMC_FAILED
<Cpu2> e800009802e00000  0000000000000000  CC_ERR_CHECK_HPMC
<Cpu2> 37000f7302e00000  8040004000000000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu2> 4000109f02e00000  0000000000000000  CC_MC_HPMC_INITIATED
<Cpu2> 4000101902e00000  0000000000000000  CC_MC_MULTIPLE_HPMCS
<Cpu2> 030010d502e00000  0000000000000000  CC_CPU_STOP

The address problem can be seen by dumping the fault vector:

0000000040159000 <fault_vector_20>:
    40159000:   63 6f 77 73     stb r15,-2447(dp)
    40159004:   20 63 61 6e     ldil L%b747000,r3
    40159008:   20 66 6c 79     ldil L%-1c3b3000,r3
        ...
    40159020:   08 00 02 40     nop
    40159024:   20 6e 60 02     ldil L%15d000,r3
    40159028:   34 63 00 00     ldo 0(r3),r3
    4015902c:   e8 60 c0 02     bv,n r0(r3)
    40159030:   08 00 02 40     nop
    40159034:   00 00 00 00     break 0,0
    40159038:   c0 00 70 00     bb,*< r0,sar,40159840 <fault_vector_20+0x840>
    4015903c:   00 00 00 00     break 0,0

Location 40159038 should contain the physical address of os_hpmc:

000000004015d000 <os_hpmc>:
    4015d000:   08 1a 02 43     copy r26,r3
    4015d004:   01 c0 08 a4     mfctl iva,r4
    4015d008:   48 85 00 68     ldw 34(r4),r5

This patch moves the address setup into initialize_ivt to resolve the
above problem.  I tested the change by dumping the HPMC entry after setup:

0000000040209020:  8000240
0000000040209024: 206a2004
0000000040209028: 34630ac0
000000004020902c: e860c002
0000000040209030:  8000240
0000000040209034: 1bdddce6
0000000040209038:   15d000
000000004020903c:      1a0
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Helge Deller <deller@gmx.de>

In the C-code we need to put the physical address of the hpmc handler in
the interrupt vector table (IVA) in order to get HPMCs working.  Since
on parisc64 function pointers are indirect (in fact they are function
descriptors) we instead export the address as variable and not as
function.

This reverts a small part of commit f39cce65 ("parisc: Add
cfi_startproc and cfi_endproc to assembly code").
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org>    [4.9+]

Fix a long-existing small nasty bug in the map_pages() implementation which
leads to overwriting already written pte entries with zero, *if* map_pages() is
called a second time with an end address which isn't aligned on a pmd boundry.
This happens for example if we want to remap only the text segment read/write
in order to run alternative patching on the code. Exiting the loop when we
reach the end address fixes this.

Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>

This patch may resolve some races in TLB handling.  Hopefully, TLB
inserts are accesses and protected by spin lock.

If not, we may need to IPI calls and do local purges on PA 2.0.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

This patch updates the spin unlock code to use an ordered store with
release semanatics.  All prior accesses are guaranteed to be performed
before an ordered store is performed.

Using an ordered store is significantly faster than using the sync
memory barrier.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

While playing with qemu with an emulated RT8139cp NIC, I faced lots of
the following warnings:
Dino 0x00810000: stuck interrupt 2

This patch ratelimits this warning and reports back that the IRQ was
handled.
Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

On kernel crash, this is the current output:
Kernel Fault: Code=26 (Data memory access rights trap) regs=(ptrval) (Addr=00000004)

Drop the address of regs, it's of no use for debugging, and show the
faulty address without parenthesis.
Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

This change removes the PTE load and present check from the L2_ptep
macro.  The load and check for kernel pages is now done in the tlb_lock
macro.  This avoids a double load and check for user pages.  The load
and check for user pages is now done inside the lock so the fault
handler can't be called while the entry is being updated.  This version
uses an ordered store to release the lock when the page table entry
isn't present.  It also corrects the check in the non SMP case.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

On boot (mostly reboot), my c8000 sometimes crashes after it prints the
TLB flush threshold.  The lockup is hard.  The front LED flashes red and
the box must be unplugged to reset the error.

I noticed that when the crash occurs the TLB flush threshold is about
one quarter what it is on a successful boot.  If I disabled the
calculation, the crash didn't occur.  There also seemed to be a timing
dependency affecting the crash.  I finally realized that the
flush_tlb_all() timing test runs just after the secondary CPUs are
started.  There seems to be a problem with running flush_tlb_all() too
soon after the CPUs are started.

The timing for the range test always seemed okay.  So, I reversed the
order of the two timing tests and I haven't had a crash at this point so
far.

I added a couple of information messages which I have left to help with
diagnosis if the problem should appear on another machine.

This version reduces the minimum TLB flush threshold to 16 KiB.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

This driver has never been wired up due to the life of the Linux
git tree, and has severely bitrotted.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Helge Deller <deller@gmx.de>

Commit cafa0010 ("Raise the minimum required gcc version to 4.6")
bumped the minimum GCC version to 4.6 for all architectures.

The version check in arch/parisc/Makefile is obsolete now.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Helge Deller <deller@gmx.de>

Fixes: 5b00ca0b ("parisc: Restore possibility to execute 64-bit applications")
Signed-off-by: Helge Deller <deller@gmx.de>

I wrote:
  "Char/Misc fixes for 4.19-rc7

   Here are 8 small fixes for some char/misc driver issues

   Included here are:
	- fpga driver fixes
	- thunderbolt bugfixes
	- firmware core revert/fix
	- hv core fix
	- hv tool fix

   All of these have been in linux-next with no reported issues."

* tag 'char-misc-4.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  thunderbolt: Initialize after IOMMUs
  thunderbolt: Do not handle ICM events after domain is stopped
  firmware: Always initialize the fw_priv list object
  docs: fpga: document fpga manager flags
  fpga: bridge: fix obvious function documentation error
  tools: hv: fcopy: set 'error' in case an unknown operation was requested
  fpga: do not access region struct after fpga_region_unregister
  Drivers: hv: vmbus: Use get/put_cpu() in vmbus_connect()

I wrote:
  "Serial driver fixes for 4.19-rc7

   Here are 3 small serial driver fixes for 4.19-rc7
    - 2 sh-sci bugfixes for reported issues
    - a revert of the PM handling for the 8250_dw code

   All of these have been in linux-next with no reported issues."

* tag 'tty-4.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  Revert "serial: sh-sci: Allow for compressed SCIF address"
  Revert "serial: sh-sci: Remove SCIx_RZ_SCIFA_REGTYPE"
  Revert "serial: 8250_dw: Fix runtime PM handling"

I wrote:
  "USB fixes for 4.19-rc7

   Here are some small USB fixes for 4.19-rc7

   These include:
     - the usual xhci bugfixes for reported issues
     - some new serial driver device ids
     - bugfix for the option serial driver for some devices
     - bugfix for the cdc_acm driver that has been there for a long time.

   All of these have been in linux-next for a while with no reported
   issues."

* tag 'usb-4.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: xhci-mtk: resume USB3 roothub first
  xhci: Add missing CAS workaround for Intel Sunrise Point xHCI
  usb: cdc_acm: Do not leak URB buffers
  USB: serial: simple: add Motorola Tetra MTP6550 id
  USB: serial: option: add two-endpoints device-id flag
  USB: serial: option: improve Quectel EP06 detection

Wolfram writes:
  "i2c for 4.19

   I2C has three driver bugfixes and a fix for a typo for you."

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: designware: Call i2c_dw_clk_rate() only when calculating timings
  i2c: i2c-scmi: fix for i2c_smbus_write_block_data
  i2c: i2c-isch: fix spelling mistake "unitialized" -> "uninitialized"
  i2c: i2c-qcom-geni: Properly handle DMA safe buffers

James writes:
  "SCSI fixes on 20181006

   Small fix for an unititialized mutex in the qedi driver."

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: qedi: Initialize the stats mutex lock

Michael writes:
  "powerpc fixes for 4.19 #4

   Four regression fixes.

   A fix for a change to lib/xz which broke our zImage loader when
   building with XZ compression. OK'ed by Herbert who merged the
   original patch.

   The recent fix we did to avoid patching __init text broke some 32-bit
   machines, fix that.

   Our show_user_instructions() could be tricked into printing kernel
   memory, add a check to avoid that.

   And a fix for a change to our NUMA initialisation logic, which causes
   crashes in some kdump configurations.

   Thanks to:
     Christophe Leroy, Hari Bathini, Jann Horn, Joel Stanley, Meelis
     Roos, Murilo Opsfelder Araujo, Srikar Dronamraju."

* tag 'powerpc-4.19-4' of https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/numa: Skip onlining a offline node in kdump path
  powerpc: Don't print kernel instructions in show_user_instructions()
  powerpc/lib: fix book3s/32 boot failure due to code patching
  lib/xz: Put CRC32_POLY_LE in xz_private.h

Dave writes:
  "Networking fixes:

  1) Fix truncation of 32-bit right shift in bpf, from Jann Horn.

  2) Fix memory leak in wireless wext compat, from Stefan Seyfried.

  3) Use after free in cfg80211's reg_process_hint(), from Yu Zhao.

  4) Need to cancel pending work when unbinding in smsc75xx otherwise
     we oops, also from Yu Zhao.

  5) Don't allow enslaving a team device to itself, from Ido Schimmel.

  6) Fix backwards compat with older userspace for rtnetlink FDB dumps.
     From Mauricio Faria.

  7) Add validation of tc policy netlink attributes, from David Ahern.

  8) Fix RCU locking in rawv6_send_hdrinc(), from Wei Wang."

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (26 commits)
  net: mvpp2: Extract the correct ethtype from the skb for tx csum offload
  ipv6: take rcu lock in rawv6_send_hdrinc()
  net: sched: Add policy validation for tc attributes
  rtnetlink: fix rtnl_fdb_dump() for ndmsg header
  yam: fix a missing-check bug
  net: bpfilter: Fix type cast and pointer warnings
  net: cxgb3_main: fix a missing-check bug
  bpf: 32-bit RSH verification must truncate input before the ALU op
  net: phy: phylink: fix SFP interface autodetection
  be2net: don't flip hw_features when VXLANs are added/deleted
  net/packet: fix packet drop as of virtio gso
  net: dsa: b53: Keep CPU port as tagged in all VLANs
  openvswitch: load NAT helper
  bnxt_en: get the reduced max_irqs by the ones used by RDMA
  bnxt_en: free hwrm resources, if driver probe fails.
  bnxt_en: Fix enables field in HWRM_QUEUE_COS2BW_CFG request
  bnxt_en: Fix VNIC reservations on the PF.
  team: Forbid enslaving team device to itself
  net/usb: cancel pending work when unbinding smsc75xx
  mlxsw: spectrum: Delete RIF when VLAN device is removed
  ...

* akpm:
  mm: madvise(MADV_DODUMP): allow hugetlbfs pages
  ocfs2: fix locking for res->tracking and dlm->tracking_list
  mm/vmscan.c: fix int overflow in callers of do_shrink_slab()
  mm/vmstat.c: skip NR_TLB_REMOTE_FLUSH* properly
  mm/vmstat.c: fix outdated vmstat_text
  proc: restrict kernel stack dumps to root
  mm/hugetlb: add mmap() encodings for 32MB and 512MB page sizes
  mm/migrate.c: split only transparent huge pages when allocation fails
  ipc/shm.c: use ERR_CAST() for shm_lock() error return
  mm/gup_benchmark: fix unsigned comparison to zero in __gup_benchmark_ioctl
  mm, thp: fix mlocking THP page with migration enabled
  ocfs2: fix crash in ocfs2_duplicate_clusters_by_page()
  hugetlb: take PMD sharing into account when flushing tlb/caches
  mm: migration: fix migration of huge PMD shared pages

Reproducer, assuming 2M of hugetlbfs available:

Hugetlbfs mounted, size=2M and option user=testuser

  # mount | grep ^hugetlbfs
  hugetlbfs on /dev/hugepages type hugetlbfs (rw,pagesize=2M,user=dan)
  # sysctl vm.nr_hugepages=1
  vm.nr_hugepages = 1
  # grep Huge /proc/meminfo
  AnonHugePages:         0 kB
  ShmemHugePages:        0 kB
  HugePages_Total:       1
  HugePages_Free:        1
  HugePages_Rsvd:        0
  HugePages_Surp:        0
  Hugepagesize:       2048 kB
  Hugetlb:            2048 kB

Code:

  #include <sys/mman.h>
  #include <stddef.h>
  #define SIZE 2*1024*1024
  int main()
  {
    void *ptr;
    ptr = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_HUGETLB | MAP_ANONYMOUS, -1, 0);
    madvise(ptr, SIZE, MADV_DONTDUMP);
    madvise(ptr, SIZE, MADV_DODUMP);
  }

Compile and strace:

  mmap(NULL, 2097152, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, -1, 0) = 0x7ff7c9200000
  madvise(0x7ff7c9200000, 2097152, MADV_DONTDUMP) = 0
  madvise(0x7ff7c9200000, 2097152, MADV_DODUMP) = -1 EINVAL (Invalid argument)

hugetlbfs pages have VM_DONTEXPAND in the VmFlags driver pages based on
author testing with analysis from Florian Weimer[1].

The inclusion of VM_DONTEXPAND into the VM_SPECIAL defination was a
consequence of the large useage of VM_DONTEXPAND in device drivers.

A consequence of [2] is that VM_DONTEXPAND marked pages are unable to be
marked DODUMP.

A user could quite legitimately madvise(MADV_DONTDUMP) their hugetlbfs
memory for a while and later request that madvise(MADV_DODUMP) on the same
memory.  We correct this omission by allowing madvice(MADV_DODUMP) on
hugetlbfs pages.

[1] https://stackoverflow.com/questions/52548260/madvisedodump-on-the-same-ptr-size-as-a-successful-madvisedontdump-fails-wit
[2] commit 0103bd16 ("mm: prepare VM_DONTDUMP for using in drivers")

Link: http://lkml.kernel.org/r/20180930054629.29150-1-daniel@linux.ibm.com
Link: https://lists.launchpad.net/maria-discuss/msg05245.html
Fixes: 0103bd16 ("mm: prepare VM_DONTDUMP for using in drivers")
Reported-by: Kenneth Penza <kpenza@gmail.com>
Signed-off-by: Daniel Black <daniel@linux.ibm.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In dlm_init_lockres() we access and modify res->tracking and
dlm->tracking_list without holding dlm->track_lock.  This can cause list
corruptions and can end up in kernel panic.

Fix this by locking res->tracking and dlm->tracking_list with
dlm->track_lock instead of dlm->spinlock.

Link: http://lkml.kernel.org/r/1529951192-4686-1-git-send-email-ashish.samant@oracle.comSigned-off-by: Ashish Samant <ashish.samant@oracle.com>
Reviewed-by: Changwei Ge <ge.changwei@h3c.com>
Acked-by: Joseph Qi <jiangqi903@gmail.com>
Acked-by: Jun Piao <piaojun@huawei.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <ge.changwei@h3c.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

do_shrink_slab() returns unsigned long value, and the placing into int
variable cuts high bytes off.  Then we compare ret and 0xfffffffe (since
SHRINK_EMPTY is converted to ret type).

Thus a large number of objects returned by do_shrink_slab() may be
interpreted as SHRINK_EMPTY, if low bytes of their value are equal to
0xfffffffe.  Fix that by declaration ret as unsigned long in these
functions.

Link: http://lkml.kernel.org/r/153813407177.17544.14888305435570723973.stgit@localhost.localdomainSigned-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reported-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

5dd0b16c ("mm/vmstat: Make NR_TLB_REMOTE_FLUSH_RECEIVED available even
on UP") made the availability of the NR_TLB_REMOTE_FLUSH* counters inside
the kernel unconditional to reduce #ifdef soup, but (either to avoid
showing dummy zero counters to userspace, or because that code was missed)
didn't update the vmstat_array, meaning that all following counters would
be shown with incorrect values.

This only affects kernel builds with
CONFIG_VM_EVENT_COUNTERS=y && CONFIG_DEBUG_TLBFLUSH=y && CONFIG_SMP=n.

Link: http://lkml.kernel.org/r/20181001143138.95119-2-jannh@google.com
Fixes: 5dd0b16c ("mm/vmstat: Make NR_TLB_REMOTE_FLUSH_RECEIVED available even on UP")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Kemi Wang <kemi.wang@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

7a9cdebd ("mm: get rid of vmacache_flush_all() entirely") removed the
VMACACHE_FULL_FLUSHES statistics, but didn't remove the corresponding
entry in vmstat_text.  This causes an out-of-bounds access in
vmstat_show().

Luckily this only affects kernels with CONFIG_DEBUG_VM_VMACACHE=y, which
is probably very rare.

Link: http://lkml.kernel.org/r/20181001143138.95119-1-jannh@google.com
Fixes: 7a9cdebd ("mm: get rid of vmacache_flush_all() entirely")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Kemi Wang <kemi.wang@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently, you can use /proc/self/task/*/stack to cause a stack walk on
a task you control while it is running on another CPU.  That means that
the stack can change under the stack walker.  The stack walker does
have guards against going completely off the rails and into random
kernel memory, but it can interpret random data from your kernel stack
as instruction pointers and stack pointers.  This can cause exposure of
kernel stack contents to userspace.

Restrict the ability to inspect kernel stacks of arbitrary tasks to root
in order to prevent a local attacker from exploiting racy stack unwinding
to leak kernel task stack contents.  See the added comment for a longer
rationale.

There don't seem to be any users of this userspace API that can't
gracefully bail out if reading from the file fails.  Therefore, I believe
that this change is unlikely to break things.  In the case that this patch
does end up needing a revert, the next-best solution might be to fake a
single-entry stack based on wchan.

Link: http://lkml.kernel.org/r/20180927153316.200286-1-jannh@google.com
Fixes: 2ec220e2 ("proc: add /proc/*/stack")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ken Chen <kenchen@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ARM64 architecture also supports 32MB and 512MB HugeTLB page sizes.  This
just adds mmap() system call argument encoding for them.

Link: http://lkml.kernel.org/r/1537841300-6979-1-git-send-email-anshuman.khandual@arm.comSigned-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

split_huge_page_to_list() fails on HugeTLB pages.  I was experimenting
with moving 32MB contig HugeTLB pages on arm64 (with a debug patch
applied) and hit the following stack trace when the kernel crashed.

[ 3732.462797] Call trace:
[ 3732.462835]  split_huge_page_to_list+0x3b0/0x858
[ 3732.462913]  migrate_pages+0x728/0xc20
[ 3732.462999]  soft_offline_page+0x448/0x8b0
[ 3732.463097]  __arm64_sys_madvise+0x724/0x850
[ 3732.463197]  el0_svc_handler+0x74/0x110
[ 3732.463297]  el0_svc+0x8/0xc
[ 3732.463347] Code: d1000400 f90b0e60 f2fbd5a2 a94982a1 (f9000420)

When unmap_and_move[_huge_page]() fails due to lack of memory, the
splitting should happen only for transparent huge pages not for HugeTLB
pages.  PageTransHuge() returns true for both THP and HugeTLB pages.
Hence the conditonal check should test PagesHuge() flag to make sure that
given pages is not a HugeTLB one.

Link: http://lkml.kernel.org/r/1537798495-4996-1-git-send-email-anshuman.khandual@arm.com
Fixes: 94723aaf ("mm: unclutter THP migration")
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This uses ERR_CAST() instead of an open-coded cast, as it is casting
across structure pointers, which upsets __randomize_layout:

ipc/shm.c: In function `shm_lock':
ipc/shm.c:209:9: note: randstruct: casting between randomized structure pointer types (ssa): `struct shmid_kernel' and `struct kern_ipc_perm'

  return (void *)ipcp;
         ^~~~~~~~~~~~

Link: http://lkml.kernel.org/r/20180919180722.GA15073@beast
Fixes: 82061c57 ("ipc: drop ipc_lock()")
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

get_user_pages_fast() will return negative value if no pages were pinned,
then be converted to a unsigned, which is compared to zero, giving the
wrong result.

Link: http://lkml.kernel.org/r/20180921095015.26088-1-yuehaibing@huawei.com
Fixes: 09e35a4a ("mm/gup_benchmark: handle gup failures")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

A transparent huge page is represented by a single entry on an LRU list.
Therefore, we can only make unevictable an entire compound page, not
individual subpages.

If a user tries to mlock() part of a huge page, we want the rest of the
page to be reclaimable.

We handle this by keeping PTE-mapped huge pages on normal LRU lists: the
PMD on border of VM_LOCKED VMA will be split into PTE table.

Introduction of THP migration breaks[1] the rules around mlocking THP
pages.  If we had a single PMD mapping of the page in mlocked VMA, the
page will get mlocked, regardless of PTE mappings of the page.

For tmpfs/shmem it's easy to fix by checking PageDoubleMap() in
remove_migration_pmd().

Anon THP pages can only be shared between processes via fork().  Mlocked
page can only be shared if parent mlocked it before forking, otherwise CoW
will be triggered on mlock().

For Anon-THP, we can fix the issue by munlocking the page on removing PTE
migration entry for the page.  PTEs for the page will always come after
mlocked PMD: rmap walks VMAs from oldest to newest.

Test-case:

	#include <unistd.h>
	#include <sys/mman.h>
	#include <sys/wait.h>
	#include <linux/mempolicy.h>
	#include <numaif.h>

	int main(void)
	{
	        unsigned long nodemask = 4;
	        void *addr;

		addr = mmap((void *)0x20000000UL, 2UL << 20, PROT_READ | PROT_WRITE,
			MAP_PRIVATE | MAP_ANONYMOUS | MAP_LOCKED, -1, 0);

	        if (fork()) {
			wait(NULL);
			return 0;
	        }

	        mlock(addr, 4UL << 10);
	        mbind(addr, 2UL << 20, MPOL_PREFERRED | MPOL_F_RELATIVE_NODES,
	                &nodemask, 4, MPOL_MF_MOVE);

	        return 0;
	}

[1] https://lkml.kernel.org/r/CAOMGZ=G52R-30rZvhGxEbkTw7rLLwBGadVYeo--iizcD3upL3A@mail.gmail.com

Link: http://lkml.kernel.org/r/20180917133816.43995-1-kirill.shutemov@linux.intel.com
Fixes: 616b8371 ("mm: thp: enable thp migration in generic path")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Reviewed-by: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>	[4.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ocfs2_duplicate_clusters_by_page() may crash if one of the extent's pages
is dirty.  When a page has not been written back, it is still in dirty
state.  If ocfs2_duplicate_clusters_by_page() is called against the dirty
page, the crash happens.

To fix this bug, we can just unlock the page and wait until the page until
its not dirty.

The following is the backtrace:

kernel BUG at /root/code/ocfs2/refcounttree.c:2961!
[exception RIP: ocfs2_duplicate_clusters_by_page+822]
__ocfs2_move_extent+0x80/0x450 [ocfs2]
? __ocfs2_claim_clusters+0x130/0x250 [ocfs2]
ocfs2_defrag_extent+0x5b8/0x5e0 [ocfs2]
__ocfs2_move_extents_range+0x2a4/0x470 [ocfs2]
ocfs2_move_extents+0x180/0x3b0 [ocfs2]
? ocfs2_wait_for_recovery+0x13/0x70 [ocfs2]
ocfs2_ioctl_move_extents+0x133/0x2d0 [ocfs2]
ocfs2_ioctl+0x253/0x640 [ocfs2]
do_vfs_ioctl+0x90/0x5f0
SyS_ioctl+0x74/0x80
do_syscall_64+0x74/0x140
entry_SYSCALL_64_after_hwframe+0x3d/0xa2

Once we find the page is dirty, we do not wait until it's clean, rather we
use write_one_page() to write it back

Link: http://lkml.kernel.org/r/20180829074740.9438-1-lchen@suse.com
[lchen@suse.com: update comments]
  Link: http://lkml.kernel.org/r/20180830075041.14879-1-lchen@suse.com
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Larry Chen <lchen@suse.com>
Acked-by: Changwei Ge <ge.changwei@h3c.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When fixing an issue with PMD sharing and migration, it was discovered via
code inspection that other callers of huge_pmd_unshare potentially have an
issue with cache and tlb flushing.

Use the routine adjust_range_if_pmd_sharing_possible() to calculate worst
case ranges for mmu notifiers.  Ensure that this range is flushed if
huge_pmd_unshare succeeds and unmaps a PUD_SUZE area.

Link: http://lkml.kernel.org/r/20180823205917.16297-3-mike.kravetz@oracle.comSigned-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The page migration code employs try_to_unmap() to try and unmap the source
page.  This is accomplished by using rmap_walk to find all vmas where the
page is mapped.  This search stops when page mapcount is zero.  For shared
PMD huge pages, the page map count is always 1 no matter the number of
mappings.  Shared mappings are tracked via the reference count of the PMD
page.  Therefore, try_to_unmap stops prematurely and does not completely
unmap all mappings of the source page.

This problem can result is data corruption as writes to the original
source page can happen after contents of the page are copied to the target
page.  Hence, data is lost.

This problem was originally seen as DB corruption of shared global areas
after a huge page was soft offlined due to ECC memory errors.  DB
developers noticed they could reproduce the issue by (hotplug) offlining
memory used to back huge pages.  A simple testcase can reproduce the
problem by creating a shared PMD mapping (note that this must be at least
PUD_SIZE in size and PUD_SIZE aligned (1GB on x86)), and using
migrate_pages() to migrate process pages between nodes while continually
writing to the huge pages being migrated.

To fix, have the try_to_unmap_one routine check for huge PMD sharing by
calling huge_pmd_unshare for hugetlbfs huge pages.  If it is a shared
mapping it will be 'unshared' which removes the page table entry and drops
the reference on the PMD page.  After this, flush caches and TLB.

mmu notifiers are called before locking page tables, but we can not be
sure of PMD sharing until page tables are locked.  Therefore, check for
the possibility of PMD sharing before locking so that notifiers can
prepare for the worst possible case.

Link: http://lkml.kernel.org/r/20180823205917.16297-2-mike.kravetz@oracle.com
[mike.kravetz@oracle.com: make _range_in_vma() a static inline]
  Link: http://lkml.kernel.org/r/6063f215-a5c8-2f0c-465a-2c515ddc952d@oracle.com
Fixes: 39dde65c ("shared page table for hugetlb page")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Bjorn writes:
  "PCI fixes for v4.19:

   - Reprogram bridge prefetch registers to fix NVIDIA and Radeon issues
     after suspend/resume (Daniel Drake)

   - Fix mvebu I/O mapping creation sequence (Thomas Petazzoni)

   - Fix minor MAINTAINERS file match issue (Bjorn Helgaas)"

* tag 'pci-v4.19-fixes-3' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: mvebu: Fix PCI I/O mapping creation sequence
  MAINTAINERS: Remove obsolete drivers/pci pattern from ACPI section
  PCI: Reprogram bridge prefetch registers on resume