When ext4 file systems were created intentionally with 128 byte inodes,
the rate-limited warning of eventual possible timestamp overflow are
still emitted rather frequently.  Remove the warning for now.

Discussion for whether any warning is needed,
and where it should be emitted, can be found at
https://lore.kernel.org/lkml/1567523922.5576.57.camel@lca.pw/.
I can post a separate follow-up patch after the conclusion.
Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

The series is an update and a more complete version of the
previously posted series at
https://lore.kernel.org/linux-fsdevel/20180122020426.2988-1-deepa.kernel@gmail.com/

Thanks to Arnd Bergmann for doing a few preliminary reviews.
They helped me fix a few issues I had overlooked.

The limits (sometimes granularity also) for the filesystems updated here are according to the
following table:

File system   Time type                      Start year Expiration year Granularity
cramfs        fixed                          0          0
romfs         fixed                          0          0
pstore        ascii seconds (27 digit ascii) S64_MIN    S64_MAX         1
coda          INT64                          S64_MIN    S64_MAX         1
omfs          64-bit milliseconds            0          U64_MAX/ 1000   NSEC_PER_MSEC
befs          unsigned 48-bit seconds        0          0xffffffffffff  alloc_super
bfs           unsigned 32-bit seconds        0          U32_MAX         alloc_super
efs           unsigned 32-bit seconds        0          U32_MAX         alloc_super
ext2          signed 32-bit seconds          S32_MIN    S32_MAX         alloc_super
ext3          signed 32-bit seconds          S32_MIN    S32_MAX         alloc_super
ext4 (old)    signed 32-bit seconds          S32_MIN    S32_MAX         alloc_super
ext4 (extra)  34-bit seconds, 30-bit ns      S32_MIN    0x37fffffff     1
freevxfs      u32 secs/usecs                 0          U32_MAX         alloc_super
jffs2         unsigned 32-bit seconds        0          U32_MAX         alloc_super
jfs           unsigned 32-bit seconds/ns     0          U32_MAX         1
minix         unsigned 32-bit seconds        0          U32_MAX         alloc_super
qnx4          unsigned 32-bit seconds        0          U32_MAX         alloc_super
qnx6          unsigned 32-bit seconds        0          U32_MAX         alloc_super
reiserfs      unsigned 32-bit seconds        0          U32_MAX         alloc_super
squashfs      unsigned 32-bit seconds        0          U32_MAX         alloc_super
ufs1          signed 32-bit seconds          S32_MIN    S32_MAX         NSEC_PER_SEC
ufs2          signed 64-bit seconds/u32 ns   S64_MIN    S64_MAX         1
xfs           signed 32-bit seconds/ns       S32_MIN    S32_MAX         1
ceph          unsigned 32-bit second/ns      0          U32_MAX         1000
sysv          unsigned 32-bit seconds        0          U32_MAX         alloc_super
affs          u32 day, min, ticks            1978       u32_max days    NSEC_PER_SEC
nfsv2         unsigned 32-bit seconds/ns     0          U32_MAX         1
nfsv3         unsigned 32-bit seconds/ns     0          U32_MAX         1000
nfsv4         u64 seconds/u32 ns             S64_MIN    S64_MAX         1000
isofs         u8 year since 1900 (fixable)   1900       2155            alloc_super
hpfs          unsigned 32-bit seconds        1970       2106            alloc_super
fat           7-bit years, 2s resolution     1980       2107
cifs (smb)    7-bit years                    1980       2107
cifs (modern) 64-bit 100ns since 1601        1601       30828
9p (9P2000)   unsigned 32-bit seconds        1970       2106
9p (9P2000.L) signed 64-bit seconds, ns      1970       S64_MAX

Granularity column filled in by the alloc_super() in the above table indicates that
the granularity is NSEC_PER_SEC.
Note that anything not mentioned above still has the default limits
S64_MIN..S64_MAX.

The patches in the series are as structured below:
1. Add vfs support to maintain the limits per filesystem.
2. Add a new timestamp_truncate() api for clamping timestamps
   according to the filesystem limits.
3. Add a warning for mount syscall to indicate the impending
   expiry of timestamps.
4. Modify utimes to clamp the timestamps.
5. Fill in limits for filesystems.

A test for checking file system timestamp limits has been posted
at https://www.spinics.net/lists/fstests/msg12262.html

Changes since v8:
* Dropped orangefs patch because of ongoing discussion
* Dropped adfs patch because a conflict with Russell's ADFS series
Changes since v7:
* Dropped fat modifications from timespec_truncate patch
* Leverage timestamp_truncate function in utimes
* Added a fix for pstore ramoops timestamps
* Added ext4 warning for inodes without room for extended timestamps.
* Made mount warning more human readable
Changes since v6:
* No change in mount behavior because of expiry of timestamps.
* Included limits for more filesystems.
Changes since v5:
* Dropped y2038-specific changes
Changes since v4:
* Added documentation for boot param
Changes since v3:
* Remove redundant initializations in libfs.c
* Change early_param to __setup similar to other root mount options.
* Fix documentation warning
Changes since v2:
* Introduce early boot param override for checks.
* Drop afs patch for timestamp limits.
Changes since v1:
* return EROFS on mount errors
* fix mtime copy/paste error in utimes

* 'limits' of https://github.com/deepa-hub/vfs:
  isofs: Initialize filesystem timestamp ranges
  pstore: fs superblock limits
  fs: omfs: Initialize filesystem timestamp ranges
  fs: hpfs: Initialize filesystem timestamp ranges
  fs: ceph: Initialize filesystem timestamp ranges
  fs: sysv: Initialize filesystem timestamp ranges
  fs: affs: Initialize filesystem timestamp ranges
  fs: fat: Initialize filesystem timestamp ranges
  fs: cifs: Initialize filesystem timestamp ranges
  fs: nfs: Initialize filesystem timestamp ranges
  ext4: Initialize timestamps limits
  9p: Fill min and max timestamps in sb
  fs: Fill in max and min timestamps in superblock
  utimes: Clamp the timestamps before update
  mount: Add mount warning for impending timestamp expiry
  timestamp_truncate: Replace users of timespec64_trunc
  vfs: Add timestamp_truncate() api
  vfs: Add file timestamp range support

Link: https://lore.kernel.org/lkml/20190730014924.2193-1-deepa.kernel@gmail.com/
Link: https://lore.kernel.org/lkml/20190830154744.4868-1-deepa.kernel@gmail.com/Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Fill in the appropriate limits to avoid inconsistencies
in the vfs cached inode times when timestamps are
outside the permitted range.

Reference: http://www.ecma-international.org/publications/standards/Ecma-119.htmSigned-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>

Leaving granularity at 1ns because it is dependent on the specific
attached backing pstore module. ramoops has microsecond resolution.

Fix the readback of ramoops fractional timestamp microseconds,
which has incorrectly been reporting the value as nanoseconds.

Fixes: 3f8f80f0 ("pstore/ram: Read and write to the 'compressed' flag of pstore").
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: anton@enomsg.org
Cc: ccross@android.com
Cc: keescook@chromium.org
Cc: tony.luck@intel.com

Fill in the appropriate limits to avoid inconsistencies
in the vfs cached inode times when timestamps are
outside the permitted range.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Bob Copeland <me@bobcopeland.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: me@bobcopeland.com
Cc: linux-karma-devel@lists.sourceforge.net

Fill in the appropriate limits to avoid inconsistencies
in the vfs cached inode times when timestamps are
outside the permitted range.

Also change the local_to_gmt() to use time64_t instead
of time32_t.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: mikulas@artax.karlin.mff.cuni.cz

Fill in the appropriate limits to avoid inconsistencies
in the vfs cached inode times when timestamps are
outside the permitted range.

According to the disscussion in
https://patchwork.kernel.org/patch/8308691/ we agreed to use
unsigned 32 bit timestamps on ceph.
Update the limits accordingly.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: zyan@redhat.com
Cc: sage@redhat.com
Cc: idryomov@gmail.com
Cc: ceph-devel@vger.kernel.org

Fill in the appropriate limits to avoid inconsistencies
in the vfs cached inode times when timestamps are
outside the permitted range.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: hch@infradead.org

Fill in the appropriate limits to avoid inconsistencies
in the vfs cached inode times when timestamps are
outside the permitted range.

Also fix timestamp calculation to avoid overflow
while converting from days to seconds.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: David Sterba <dsterba@suse.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: dsterba@suse.com

Fill in the appropriate limits to avoid inconsistencies
in the vfs cached inode times when timestamps are
outside the permitted range.

Some FAT variants indicate that the years after 2099 are not supported.
Since commit 7decd1cb ("fat: Fix and cleanup timestamp conversion")
we support the full range of years that can be represented, up to 2107.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: hirofumi@mail.parknet.co.jp

Fill in the appropriate limits to avoid inconsistencies
in the vfs cached inode times when timestamps are
outside the permitted range.

Also fixed cnvrtDosUnixTm calculations to avoid int overflow
while computing maximum date.

References:

http://cifs.com/

https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-cifs/d416ff7c-c536-406e-a951-4f04b2fd1d2bSigned-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: sfrench@samba.org
Cc: linux-cifs@vger.kernel.org

Fill in the appropriate limits to avoid inconsistencies
in the vfs cached inode times when timestamps are
outside the permitted range.

The time formats for various verious is detailed in the
RFCs as below:

https://tools.ietf.org/html/rfc7862(time metadata)
https://tools.ietf.org/html/rfc7530:

nfstime4

   struct nfstime4 {
           int64_t         seconds;
           uint32_t        nseconds;
   };

https://tools.ietf.org/html/rfc1094

          struct timeval {
              unsigned int seconds;
              unsigned int useconds;
          };

https://tools.ietf.org/html/rfc1813

struct nfstime3 {
         uint32   seconds;
         uint32   nseconds;
      };

Use the limits as per the RFC.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: trond.myklebust@hammerspace.com
Cc: anna.schumaker@netapp.com
Cc: linux-nfs@vger.kernel.org

ext4 has different overflow limits for max filesystem
timestamps based on the extra bytes available.

The timestamp limits are calculated according to the
encoding table in
a4dad1aei(ext4: Fix handling of extended tv_sec):

* extra  msb of                         adjust for signed
* epoch  32-bit                         32-bit tv_sec to
* bits   time    decoded 64-bit tv_sec  64-bit tv_sec      valid time range
* 0 0    1    -0x80000000..-0x00000001  0x000000000   1901-12-13..1969-12-31
* 0 0    0    0x000000000..0x07fffffff  0x000000000   1970-01-01..2038-01-19
* 0 1    1    0x080000000..0x0ffffffff  0x100000000   2038-01-19..2106-02-07
* 0 1    0    0x100000000..0x17fffffff  0x100000000   2106-02-07..2174-02-25
* 1 0    1    0x180000000..0x1ffffffff  0x200000000   2174-02-25..2242-03-16
* 1 0    0    0x200000000..0x27fffffff  0x200000000   2242-03-16..2310-04-04
* 1 1    1    0x280000000..0x2ffffffff  0x300000000   2310-04-04..2378-04-22
* 1 1    0    0x300000000..0x37fffffff  0x300000000   2378-04-22..2446-05-10

Note that the time limits are not correct for deletion times.

Added a warn when an inode cannot be extended to incorporate an
extended timestamp.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: tytso@mit.edu
Cc: adilger.kernel@dilger.ca
Cc: linux-ext4@vger.kernel.org

struct p9_wstat and struct p9_stat_dotl indicate that the
wire transport uses u32 and u64 fields for timestamps.
Fill in the appropriate limits to avoid inconsistencies in
the vfs cached inode times when timestamps are outside the
permitted range.

Note that the upper bound for V9FS_PROTO_2000L is retained as S64_MAX.
This is because that is the upper bound supported by vfs.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: ericvh@gmail.com
Cc: lucho@ionkov.net
Cc: asmadeus@codewreck.org
Cc: v9fs-developer@lists.sourceforge.net

Fill in the appropriate limits to avoid inconsistencies
in the vfs cached inode times when timestamps are
outside the permitted range.

Even though some filesystems are read-only, fill in the
timestamps to reflect the on-disk representation.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-By: Tigran Aivazian <aivazian.tigran@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: aivazian.tigran@gmail.com
Cc: al@alarsen.net
Cc: coda@cs.cmu.edu
Cc: darrick.wong@oracle.com
Cc: dushistov@mail.ru
Cc: dwmw2@infradead.org
Cc: hch@infradead.org
Cc: jack@suse.com
Cc: jaharkes@cs.cmu.edu
Cc: luisbg@kernel.org
Cc: nico@fluxnic.net
Cc: phillip@squashfs.org.uk
Cc: richard@nod.at
Cc: salah.triki@gmail.com
Cc: shaggy@kernel.org
Cc: linux-xfs@vger.kernel.org
Cc: codalist@coda.cs.cmu.edu
Cc: linux-ext4@vger.kernel.org
Cc: linux-mtd@lists.infradead.org
Cc: jfs-discussion@lists.sourceforge.net
Cc: reiserfs-devel@vger.kernel.org

POSIX is ambiguous on the behavior of timestamps for
futimens, utimensat and utimes. Whether to return an
error or silently clamp a timestamp beyond the range
supported by the underlying filesystems is not clear.

POSIX.1 section for futimens, utimensat and utimes says:
(http://pubs.opengroup.org/onlinepubs/9699919799/functions/futimens.html)

The file's relevant timestamp shall be set to the greatest
value supported by the file system that is not greater
than the specified time.

If the tv_nsec field of a timespec structure has the special
value UTIME_NOW, the file's relevant timestamp shall be set
to the greatest value supported by the file system that is
not greater than the current time.

[EINVAL]
    A new file timestamp would be a value whose tv_sec
    component is not a value supported by the file system.

The patch chooses to clamp the timestamps according to the
filesystem timestamp ranges and does not return an error.
This is in line with the behavior of utime syscall also
since the POSIX page(http://pubs.opengroup.org/onlinepubs/009695399/functions/utime.html)
for utime does not mention returning an error or clamping like above.

Same for utimes http://pubs.opengroup.org/onlinepubs/009695399/functions/utimes.htmlSigned-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>

The warning reuses the uptime max of 30 years used by
settimeofday().

Note that the warning is only emitted for writable filesystem mounts
through the mount syscall. Automounts do not have the same warning.

Print out the warning in human readable format using the struct tm.
After discussion with Arnd Bergmann, we chose to print only the year number.
The raw s_time_max is also displayed, and the user can easily decode
it e.g. "date -u -d @$((0x7fffffff))". We did not want to consolidate
struct rtc_tm and struct tm just to print the date using a format specifier
as part of this series.
Given that the rtc_tm is not compiled on all architectures, this is not a
trivial patch. This can be added in the future.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>

Update the inode timestamp updates to use timestamp_truncate()
instead of timespec64_trunc().

The change was mostly generated by the following coccinelle
script.

virtual context
virtual patch

@r1 depends on patch forall@
struct inode *inode;
identifier i_xtime =~ "^i_[acm]time$";
expression e;
@@

inode->i_xtime =
- timespec64_trunc(
+ timestamp_truncate(
...,
- e);
+ inode);
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: adrian.hunter@intel.com
Cc: dedekind1@gmail.com
Cc: gregkh@linuxfoundation.org
Cc: hch@lst.de
Cc: jaegeuk@kernel.org
Cc: jlbec@evilplan.org
Cc: richard@nod.at
Cc: tj@kernel.org
Cc: yuchao0@huawei.com
Cc: linux-f2fs-devel@lists.sourceforge.net
Cc: linux-ntfs-dev@lists.sourceforge.net
Cc: linux-mtd@lists.infradead.org

timespec_trunc() function is used to truncate a
filesystem timestamp to the right granularity.
But, the function does not clamp tv_sec part of the
timestamps according to the filesystem timestamp limits.

The replacement api: timestamp_truncate() also alters the
signature of the function to accommodate filesystem
timestamp clamping according to flesystem limits.

Note that the tv_nsec part is set to 0 if tv_sec is not within
the range supported for the filesystem.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>

Add fields to the superblock to track the min and max
timestamps supported by filesystems.

Initially, when a superblock is allocated, initialize
it to the max and min values the fields can hold.
Individual filesystems override these to match their
actual limits.

Pseudo filesystems are assumed to always support the
min and max allowable values for the fields.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>

Pull auxdisplay cleanup from Miguel Ojeda:
 "Make ht16k33_fb_fix and ht16k33_fb_var constant (Nishka Dasgupta)"

* tag 'auxdisplay-for-linus-v5.3-rc7' of git://github.com/ojeda/linux:
  auxdisplay: ht16k33: Make ht16k33_fb_fix and ht16k33_fb_var constant

Pull UML fix from Richard Weinberger:
 "Fix time travel mode"

* tag 'for-linus-5.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: fix time travel mode

Pull UBIFS and JFFS2 fixes from Richard Weinberger:
 "UBIFS:
   - Don't block too long in writeback_inodes_sb()
   - Fix for a possible overrun of the log head
   - Fix double unlock in orphan_delete()

  JFFS2:
   - Remove C++ style from UAPI header and unbreak picky toolchains"

* tag 'for-linus-5.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs:
  ubifs: Limit the number of pages in shrink_liability
  ubifs: Correctly initialize c->min_log_bytes
  ubifs: Fix double unlock around orphan_delete()
  jffs2: Remove C++ style comments from uapi header

Pull x86 fixes from Thomas Gleixner:
 "A few fixes for x86:

   - Fix a boot regression caused by the recent bootparam sanitizing
     change, which escaped the attention of all people who reviewed that
     code.

   - Address a boot problem on machines with broken E820 tables caused
     by an underflow which ended up placing the trampoline start at
     physical address 0.

   - Handle machines which do not advertise a legacy timer of any form,
     but need calibration of the local APIC timer gracefully by making
     the calibration routine independent from the tick interrupt. Marked
     for stable as well as there seems to be quite some new laptops
     rolled out which expose this.

   - Clear the RDRAND CPUID bit on AMD family 15h and 16h CPUs which are
     affected by broken firmware which does not initialize RDRAND
     correctly after resume. Add a command line parameter to override
     this for machine which either do not use suspend/resume or have a
     fixed BIOS. Unfortunately there is no way to detect this on boot,
     so the only safe decision is to turn it off by default.

   - Prevent RFLAGS from being clobbers in CALL_NOSPEC on 32bit which
     caused fast KVM instruction emulation to break.

   - Explain the Intel CPU model naming convention so that the repeating
     discussions come to an end"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/retpoline: Don't clobber RFLAGS during CALL_NOSPEC on i386
  x86/boot: Fix boot regression caused by bootparam sanitizing
  x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16h
  x86/boot/compressed/64: Fix boot on machines with broken E820 table
  x86/apic: Handle missing global clockevent gracefully
  x86/cpu: Explain Intel model naming convention

Pull timekeeping fix from Thomas Gleixner:
 "A single fix for a regression caused by the generic VDSO
  implementation where a math overflow causes CLOCK_BOOTTIME to become a
  random number generator"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping/vsyscall: Prevent math overflow in BOOTTIME update

Pull scheduler fix from Thomas Gleixner:
 "Handle the worker management in situations where a task is scheduled
  out on a PI lock contention correctly and schedule a new worker if
  possible"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Schedule new worker even if PI-blocked

Pull perf fixes from Thomas Gleixner:
 "Two small fixes for kprobes and perf:

   - Prevent a deadlock in kprobe_optimizer() causes by reverse lock
     ordering

   - Fix a comment typo"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kprobes: Fix potential deadlock in kprobe_optimizer()
  perf/x86: Fix typo in comment

Pull irq fix from Thomas Gleixner:
 "A single fix for a imbalanced kobject operation in the irq decriptor
  code which was unearthed by the new warnings in the kobject code"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Properly pair kobject_del() with kobject_add()

Mergr misc fixes from Andrew Morton:
 "11 fixes"

Mostly VM fixes, one psi polling fix, and one parisc build fix.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm/kasan: fix false positive invalid-free reports with CONFIG_KASAN_SW_TAGS=y
  mm/zsmalloc.c: fix race condition in zs_destroy_pool
  mm/zsmalloc.c: migration can leave pages in ZS_EMPTY indefinitely
  mm, page_owner: handle THP splits correctly
  userfaultfd_release: always remove uffd flags and clear vm_userfaultfd_ctx
  psi: get poll_work to run when calling poll syscall next time
  mm: memcontrol: flush percpu vmevents before releasing memcg
  mm: memcontrol: flush percpu vmstats before releasing memcg
  parisc: fix compilation errrors
  mm, page_alloc: move_freepages should not examine struct page of reserved memory
  mm/z3fold.c: fix race between migration and destruction

Pull dma-mapping fixes from Christoph Hellwig:
 "Two fixes for regressions in this merge window:

   - select the Kconfig symbols for the noncoherent dma arch helpers on
     arm if swiotlb is selected, not just for LPAE to not break then Xen
     build, that uses swiotlb indirectly through swiotlb-xen

   - fix the page allocator fallback in dma_alloc_contiguous if the CMA
     allocation fails"

* tag 'dma-mapping-5.3-5' of git://git.infradead.org/users/hch/dma-mapping:
  dma-direct: fix zone selection after an unaddressable CMA allocation
  arm: select the dma-noncoherent symbols for all swiotlb builds

The code like this:

	ptr = kmalloc(size, GFP_KERNEL);
	page = virt_to_page(ptr);
	offset = offset_in_page(ptr);
	kfree(page_address(page) + offset);

may produce false-positive invalid-free reports on the kernel with
CONFIG_KASAN_SW_TAGS=y.

In the example above we lose the original tag assigned to 'ptr', so
kfree() gets the pointer with 0xFF tag.  In kfree() we check that 0xFF
tag is different from the tag in shadow hence print false report.

Instead of just comparing tags, do the following:

1) Check that shadow doesn't contain KASAN_TAG_INVALID.  Otherwise it's
   double-free and it doesn't matter what tag the pointer have.

2) If pointer tag is different from 0xFF, make sure that tag in the
   shadow is the same as in the pointer.

Link: http://lkml.kernel.org/r/20190819172540.19581-1-aryabinin@virtuozzo.com
Fixes: 7f94ffbc ("kasan: add hooks implementation for tag-based mode")
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Walter Wu <walter-zh.wu@mediatek.com>
Reported-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In zs_destroy_pool() we call flush_work(&pool->free_work).  However, we
have no guarantee that migration isn't happening in the background at
that time.

Since migration can't directly free pages, it relies on free_work being
scheduled to free the pages.  But there's nothing preventing an
in-progress migrate from queuing the work *after*
zs_unregister_migration() has called flush_work().  Which would mean
pages still pointing at the inode when we free it.

Since we know at destroy time all objects should be free, no new
migrations can come in (since zs_page_isolate() fails for fully-free
zspages).  This means it is sufficient to track a "# isolated zspages"
count by class, and have the destroy logic ensure all such pages have
drained before proceeding.  Keeping that state under the class spinlock
keeps the logic straightforward.

In this case a memory leak could lead to an eventual crash if compaction
hits the leaked page.  This crash would only occur if people are
changing their zswap backend at runtime (which eventually starts
destruction).

Link: http://lkml.kernel.org/r/20190809181751.219326-2-henryburns@google.com
Fixes: 48b4800a ("zsmalloc: page migration support")
Signed-off-by: Henry Burns <henryburns@google.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Henry Burns <henrywolfeburns@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Jonathan Adams <jwadams@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In zs_page_migrate() we call putback_zspage() after we have finished
migrating all pages in this zspage.  However, the return value is
ignored.  If a zs_free() races in between zs_page_isolate() and
zs_page_migrate(), freeing the last object in the zspage,
putback_zspage() will leave the page in ZS_EMPTY for potentially an
unbounded amount of time.

To fix this, we need to do the same thing as zs_page_putback() does:
schedule free_work to occur.

To avoid duplicated code, move the sequence to a new
putback_zspage_deferred() function which both zs_page_migrate() and
zs_page_putback() call.

Link: http://lkml.kernel.org/r/20190809181751.219326-1-henryburns@google.com
Fixes: 48b4800a ("zsmalloc: page migration support")
Signed-off-by: Henry Burns <henryburns@google.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Henry Burns <henrywolfeburns@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Jonathan Adams <jwadams@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

THP splitting path is missing the split_page_owner() call that
split_page() has.

As a result, split THP pages are wrongly reported in the page_owner file
as order-9 pages.  Furthermore when the former head page is freed, the
remaining former tail pages are not listed in the page_owner file at
all.  This patch fixes that by adding the split_page_owner() call into
__split_huge_page().

Link: http://lkml.kernel.org/r/20190820131828.22684-2-vbabka@suse.cz
Fixes: a9627bc5 ("mm/page_owner: introduce split_page_owner and replace manual handling")
Reported-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

userfaultfd_release() should clear vm_flags/vm_userfaultfd_ctx even if
mm->core_state != NULL.

Otherwise a page fault can see userfaultfd_missing() == T and use an
already freed userfaultfd_ctx.

Link: http://lkml.kernel.org/r/20190820160237.GB4983@redhat.com
Fixes: 04f5866e ("coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping")
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Only when calling the poll syscall the first time can user receive
POLLPRI correctly.  After that, user always fails to acquire the event
signal.

Reproduce case:
 1. Get the monitor code in Documentation/accounting/psi.txt
 2. Run it, and wait for the event triggered.
 3. Kill and restart the process.

The question is why we can end up with poll_scheduled = 1 but the work
not running (which would reset it to 0).  And the answer is because the
scheduling side sees group->poll_kworker under RCU protection and then
schedules it, but here we cancel the work and destroy the worker.  The
cancel needs to pair with resetting the poll_scheduled flag.

Link: http://lkml.kernel.org/r/1566357985-97781-1-git-send-email-joseph.qi@linux.alibaba.comSigned-off-by: Jason Xing <kerneljasonxing@linux.alibaba.com>
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Caspar Zhang <caspar@linux.alibaba.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Similar to vmstats, percpu caching of local vmevents leads to an
accumulation of errors on non-leaf levels.  This happens because some
leftovers may remain in percpu caches, so that they are never propagated
up by the cgroup tree and just disappear into nonexistence with on
releasing of the memory cgroup.

To fix this issue let's accumulate and propagate percpu vmevents values
before releasing the memory cgroup similar to what we're doing with
vmstats.

Since on cpu hotplug we do flush percpu vmstats anyway, we can iterate
only over online cpus.

Link: http://lkml.kernel.org/r/20190819202338.363363-4-guro@fb.com
Fixes: 42a30035 ("mm: memcontrol: fix recursive statistics correctness & scalabilty")
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Percpu caching of local vmstats with the conditional propagation by the
cgroup tree leads to an accumulation of errors on non-leaf levels.

Let's imagine two nested memory cgroups A and A/B.  Say, a process
belonging to A/B allocates 100 pagecache pages on the CPU 0.  The percpu
cache will spill 3 times, so that 32*3=96 pages will be accounted to A/B
and A atomic vmstat counters, 4 pages will remain in the percpu cache.

Imagine A/B is nearby memory.max, so that every following allocation
triggers a direct reclaim on the local CPU.  Say, each such attempt will
free 16 pages on a new cpu.  That means every percpu cache will have -16
pages, except the first one, which will have 4 - 16 = -12.  A/B and A
atomic counters will not be touched at all.

Now a user removes A/B.  All percpu caches are freed and corresponding
vmstat numbers are forgotten.  A has 96 pages more than expected.

As memory cgroups are created and destroyed, errors do accumulate.  Even
1-2 pages differences can accumulate into large numbers.

To fix this issue let's accumulate and propagate percpu vmstat values
before releasing the memory cgroup.  At this point these numbers are
stable and cannot be changed.

Since on cpu hotplug we do flush percpu vmstats anyway, we can iterate
only over online cpus.

Link: http://lkml.kernel.org/r/20190819202338.363363-2-guro@fb.com
Fixes: 42a30035 ("mm: memcontrol: fix recursive statistics correctness & scalabilty")
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 0cfaee2a ("include/asm-generic/5level-fixup.h: fix variable
'p4d' set but not used") converted a few functions from macros to static
inline, which causes parisc to complain,

  In file included from include/asm-generic/4level-fixup.h:38:0,
                   from arch/parisc/include/asm/pgtable.h:5,
                   from arch/parisc/include/asm/io.h:6,
                   from include/linux/io.h:13,
                   from sound/core/memory.c:9:
  include/asm-generic/5level-fixup.h:14:18: error: unknown type name 'pgd_t'; did you mean 'pid_t'?
   #define p4d_t    pgd_t
                    ^
  include/asm-generic/5level-fixup.h:24:28: note: in expansion of macro 'p4d_t'
   static inline int p4d_none(p4d_t p4d)
                              ^~~~~

It is because "4level-fixup.h" is included before "asm/page.h" where
"pgd_t" is defined.

Link: http://lkml.kernel.org/r/20190815205305.1382-1-cai@lca.pw
Fixes: 0cfaee2a ("include/asm-generic/5level-fixup.h: fix variable 'p4d' set but not used")
Signed-off-by: Qian Cai <cai@lca.pw>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>