Patch series "Fixes for hugetlb mapcount at most 1 for shared PMDs".

This issue of mapcount in hugetlb pages referenced by shared PMDs was
discussed in [1].  The following two patches address user visible behavior
caused by this issue.

[1] https://lore.kernel.org/linux-mm/Y9BF+OCdWnCSilEu@monkey/


This patch (of 2):

A hugetlb page will have a mapcount of 1 if mapped by multiple processes
via a shared PMD.  This is because only the first process increases the
map count, and subsequent processes just add the shared PMD page to their
page table.

page_mapcount is being used to decide if a hugetlb page is shared or
private in /proc/PID/smaps.  Pages referenced via a shared PMD were
incorrectly being counted as private.

To fix, check for a shared PMD if mapcount is 1.  If a shared PMD is found
count the hugetlb page as shared.  A new helper to check for a shared PMD
is added.

[akpm@linux-foundation.org: simplification, per David]
[akpm@linux-foundation.org: hugetlb.h: include page_ref.h for page_count()]
Link: https://lkml.kernel.org/r/20230126222721.222195-2-mike.kravetz@oracle.com
Fixes: 25ee01a2 ("mm: hugetlb: proc: add hugetlb-related fields to /proc/PID/smaps")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

In commit 34488399 ("mm/madvise: add file and shmem support to
MADV_COLLAPSE") we make the following change to find_pmd_or_thp_or_none():

	-       if (!pmd_present(pmde))
	-               return SCAN_PMD_NULL;
	+       if (pmd_none(pmde))
	+               return SCAN_PMD_NONE;

This was for-use by MADV_COLLAPSE file/shmem codepaths, where
MADV_COLLAPSE might identify a pte-mapped hugepage, only to have
khugepaged race-in, free the pte table, and clear the pmd.  Such codepaths
include:

A) If we find a suitably-aligned compound page of order HPAGE_PMD_ORDER
   already in the pagecache.
B) In retract_page_tables(), if we fail to grab mmap_lock for the target
   mm/address.

In these cases, collapse_pte_mapped_thp() really does expect a none (not
just !present) pmd, and we want to suitably identify that case separate
from the case where no pmd is found, or it's a bad-pmd (of course, many
things could happen once we drop mmap_lock, and the pmd could plausibly
undergo multiple transitions due to intervening fault, split, etc). 
Regardless, the code is prepared install a huge-pmd only when the existing
pmd entry is either a genuine pte-table-mapping-pmd, or the none-pmd.

However, the commit introduces a logical hole; namely, that we've allowed
!none- && !huge- && !bad-pmds to be classified as genuine
pte-table-mapping-pmds.  One such example that could leak through are swap
entries.  The pmd values aren't checked again before use in
pte_offset_map_lock(), which is expecting nothing less than a genuine
pte-table-mapping-pmd.

We want to put back the !pmd_present() check (below the pmd_none() check),
but need to be careful to deal with subtleties in pmd transitions and
treatments by various arch.

The issue is that __split_huge_pmd_locked() temporarily clears the present
bit (or otherwise marks the entry as invalid), but pmd_present() and
pmd_trans_huge() still need to return true while the pmd is in this
transitory state.  For example, x86's pmd_present() also checks the
_PAGE_PSE , riscv's version also checks the _PAGE_LEAF bit, and arm64 also
checks a PMD_PRESENT_INVALID bit.

Covering all 4 cases for x86 (all checks done on the same pmd value):

1) pmd_present() && pmd_trans_huge()
   All we actually know here is that the PSE bit is set. Either:
   a) We aren't racing with __split_huge_page(), and PRESENT or PROTNONE
      is set.
      => huge-pmd
   b) We are currently racing with __split_huge_page().  The danger here
      is that we proceed as-if we have a huge-pmd, but really we are
      looking at a pte-mapping-pmd.  So, what is the risk of this
      danger?

      The only relevant path is:

	madvise_collapse() -> collapse_pte_mapped_thp()

      Where we might just incorrectly report back "success", when really
      the memory isn't pmd-backed.  This is fine, since split could
      happen immediately after (actually) successful madvise_collapse().
      So, it should be safe to just assume huge-pmd here.

2) pmd_present() && !pmd_trans_huge()
   Either:
   a) PSE not set and either PRESENT or PROTNONE is.
      => pte-table-mapping pmd (or PROT_NONE)
   b) devmap.  This routine can be called immediately after
      unlocking/locking mmap_lock -- or called with no locks held (see
      khugepaged_scan_mm_slot()), so previous VMA checks have since been
      invalidated.

3) !pmd_present() && pmd_trans_huge()
  Not possible.

4) !pmd_present() && !pmd_trans_huge()
  Neither PRESENT nor PROTNONE set
  => not present

I've checked all archs that implement pmd_trans_huge() (arm64, riscv,
powerpc, longarch, x86, mips, s390) and this logic roughly translates
(though devmap treatment is unique to x86 and powerpc, and (3) doesn't
necessarily hold in general -- but that doesn't matter since
!pmd_present() always takes failure path).

Also, add a comment above find_pmd_or_thp_or_none() to help future
travelers reason about the validity of the code; namely, the possible
mutations that might happen out from under us, depending on how mmap_lock
is held (if at all).

Link: https://lkml.kernel.org/r/20230125225358.2576151-1-zokeefe@google.com
Fixes: 34488399 ("mm/madvise: add file and shmem support to MADV_COLLAPSE")
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Reported-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

This reverts commit 972fa3a7.

Kmemleak operates by periodically scanning memory regions for pointers to
allocated memory blocks to determine if they are leaked or not.  However,
reserved memory regions can be used for DMA transactions between a device
and a CPU, and thus, wouldn't contain pointers to allocated memory blocks,
making them inappropriate for kmemleak to scan.  Thus, revert this commit.

Link: https://lkml.kernel.org/r/20230124230254.295589-1-isaacmanjarres@google.com
Fixes: 972fa3a7 ("mm: kmemleak: alloc gray object for reserved region with direct map")
Signed-off-by: Isaac J. Manjarres <isaacmanjarres@google.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Calvin Zhang <calvinzhang.cool@gmail.com>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: <stable@vger.kernel.org>	[5.17+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Fix a spello in freevxfs Kconfig.
(reported by codespell)

Link: https://lkml.kernel.org/r/20230124181638.15604-1-rdunlap@infradead.orgSigned-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

We should get pivots boundary by type.  Fixes a potential overindexing of
mt_pivots[].

Link: https://lkml.kernel.org/r/20221112234308.23823-1-richard.weiyang@gmail.com
Fixes: 54a611b6 ("Maple Tree: add new data structure")
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Update e-mail address.

Link: https://lkml.kernel.org/r/20230119072229.99603-1-eugen.hristev@collabora.comSigned-off-by: Eugen Hristev <eugen.hristev@collabora.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Fabian has reported another regression in 6.1 due to ca3d76b0 ("mm:
add merging after mremap resize").  The problem is that vma_merge() can
fail when vma has a vm_ops->close() method, causing is_mergeable_vma()
test to be negative.  This was happening for vma mapping a file from
fuse-overlayfs, which does have the method.  But when we are simply
expanding the vma, we never remove it due to the "merge" with the added
area, so the test should not prevent the expansion.

As a quick fix, check for such vmas and expand them using vma_adjust()
directly as was done before commit ca3d76b0.  For a more robust long
term solution we should try to limit the check for vma_ops->close only to
cases that actually result in vma removal, so that no merge would be
prevented unnecessarily.

[akpm@linux-foundation.org: fix indenting whitespace, reflow comment]
Link: https://lkml.kernel.org/r/20230117101939.9753-1-vbabka@suse.cz
Fixes: ca3d76b0 ("mm: add merging after mremap resize")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Fabian Vogt <fvogt@suse.com>
  Link: https://bugzilla.suse.com/show_bug.cgi?id=1206359#c35Tested-by: Fabian Vogt <fvogt@suse.com>
Cc: Jakub Matěna <matenajakub@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

While mounting a corrupted filesystem, a signed integer '*xattr_ids' can
become less than zero.  This leads to the incorrect computation of 'len'
and 'indexes' values which can cause null-ptr-deref in copy_bio_to_actor()
or out-of-bounds accesses in the next sanity checks inside
squashfs_read_xattr_id_table().

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Link: https://lkml.kernel.org/r/20230117105226.329303-2-pchelkin@ispras.ru
Fixes: 506220d2 ("squashfs: add more sanity checks in xattr id lookup")
Reported-by: <syzbot+082fa4af80a5bb1a9843@syzkaller.appspotmail.com>
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: Phillip Lougher <phillip@squashfs.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Since commit aa06a9bd ("ia64: fix clock_getres(CLOCK_MONOTONIC) to
report ITC frequency"), gcc 10.1.0 fails to build ia64 with the gnomic:
| ../arch/ia64/kernel/sys_ia64.c: In function 'ia64_clock_getres':
| ../arch/ia64/kernel/sys_ia64.c:189:3: error: a label can only be part of a statement and a declaration is not a statement
|   189 |   s64 tick_ns = DIV_ROUND_UP(NSEC_PER_SEC, local_cpu_data->itc_freq);

This line appears immediately after a case label in a switch.

Move the declarations out of the case, to the top of the function.

Link: https://lkml.kernel.org/r/20230117151632.393836-1-james.morse@arm.com
Fixes: aa06a9bd ("ia64: fix clock_getres(CLOCK_MONOTONIC) to report ITC frequency")
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Sergei Trofimovich <slyich@gmail.com>
Cc: Émeric Maschino <emeric.maschino@gmail.com>
Cc: matoro <matoro_mailinglist_kernel@matoro.tk>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lru_gen_migrate_mm() assumes lru_gen_add_mm() runs prior to itself.  This
isn't true for the following scenario:

    CPU 1                         CPU 2

  clone()
    cgroup_can_fork()
                                cgroup_procs_write()
    cgroup_post_fork()
                                  task_lock()
                                  lru_gen_migrate_mm()
                                  task_unlock()
    task_lock()
    lru_gen_add_mm()
    task_unlock()

And when the above happens, kernel crashes because of linked list
corruption (mm_struct->lru_gen.list).

Link: https://lore.kernel.org/r/20230115134651.30028-1-msizanoen@qtmlabs.xyz/
Link: https://lkml.kernel.org/r/20230116034405.2960276-1-yuzhao@google.com
Fixes: bd74fdae ("mm: multi-gen LRU: support page table walks")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reported-by: msizanoen <msizanoen@qtmlabs.xyz>
Tested-by: msizanoen <msizanoen@qtmlabs.xyz>
Cc: <stable@vger.kernel.org>	[6.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

This reverts commit 12a5d395.

Although it is recognized that a finer grained pro-active reclaim is
something we need and want the semantic of this implementation is really
ambiguous.

In a follow up discussion it became clear that there are two essential
usecases here.  One is to use memory.reclaim to pro-actively reclaim
memory and expectation is that the requested and reported amount of memory
is uncharged from the memcg.  Another usecase focuses on pro-active
demotion when the memory is merely shuffled around to demotion targets
while the overall charged memory stays unchanged.

The current implementation considers demoted pages as reclaimed and that
break both usecases.  [1] has tried to address the reporting part but
there are more issues with that summarized in [2] and follow up emails.

Let's revert the nodemask based extension of the memcg pro-active
reclaim for now until we settle with a more robust semantic.

[1] http://lkml.kernel.org/r/http://lkml.kernel.org/r/20221206023406.3182800-1-almasrymina@google.com
[2] http://lkml.kernel.org/r/Y5bsmpCyeryu3Zz1@dhcp22.suse.cz

Link: https://lkml.kernel.org/r/Y5xASNe1x8cusiTx@dhcp22.suse.cz
Fixes: 12a5d395 ("mm: add nodes= arg to memory.reclaim")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: zefan li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Currently, there is a race between zs_free() and zs_reclaim_page():
zs_reclaim_page() finds a handle to an allocated object, but before the
eviction happens, an independent zs_free() call to the same handle could
come in and overwrite the object value stored at the handle with the last
deferred handle.  When zs_reclaim_page() finally gets to call the eviction
handler, it will see an invalid object value (i.e the previous deferred
handle instead of the original object value).

This race happens quite infrequently.  We only managed to produce it with
out-of-tree developmental code that triggers zsmalloc writeback with a
much higher frequency than usual.

This patch fixes this race by storing the deferred handle in the object
header instead.  We differentiate the deferred handle from the other two
cases (handle for allocated object, and linkage for free object) with a
new tag.  If zspage reclamation succeeds, we will free these deferred
handles by walking through the zspage objects.  On the other hand, if
zspage reclamation fails, we reconstruct the zspage freelist (with the
deferred handle tag and allocated tag) before trying again with the
reclamation.

[arnd@arndb.de: avoid unused-function warning]
  Link: https://lkml.kernel.org/r/20230117170507.2651972-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20230110231701.326724-1-nphamcs@gmail.com
Fixes: 9997bc01 ("zsmalloc: implement writeback mechanism for zsmalloc")
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

If an ->anon_vma is attached to the VMA, collapse_and_free_pmd() requires
it to be locked.

Page table traversal is allowed under any one of the mmap lock, the
anon_vma lock (if the VMA is associated with an anon_vma), and the
mapping lock (if the VMA is associated with a mapping); and so to be
able to remove page tables, we must hold all three of them. 
retract_page_tables() bails out if an ->anon_vma is attached, but does
this check before holding the mmap lock (as the comment above the check
explains).

If we racily merged an existing ->anon_vma (shared with a child
process) from a neighboring VMA, subsequent rmap traversals on pages
belonging to the child will be able to see the page tables that we are
concurrently removing while assuming that nothing else can access them.

Repeat the ->anon_vma check once we hold the mmap lock to ensure that
there really is no concurrent page table access.

Hitting this bug causes a lockdep warning in collapse_and_free_pmd(),
in the line "lockdep_assert_held_write(&vma->anon_vma->root->rwsem)". 
It can also lead to use-after-free access.

Link: https://lore.kernel.org/linux-mm/CAG48ez3434wZBKFFbdx4M9j6eUwSUVPd4dxhzW_k_POneSDF+A@mail.gmail.com/
Link: https://lkml.kernel.org/r/20230111133351.807024-1-jannh@google.com
Fixes: f3f0e1d2 ("khugepaged: add support of collapse for tmpfs/shmem pages")
Signed-off-by: Jann Horn <jannh@google.com>
Reported-by: Zach O'Keefe <zokeefe@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@intel.linux.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mas_empty_area_rev() was not correctly validating the start of a gap
against the lower limit.  This could lead to the range starting lower than
the requested minimum.

Fix the issue by better validating a gap once one is found.

This commit also adds tests to the maple tree test suite for this issue
and tests the mas_empty_area() function for similar bound checking.

Link: https://lkml.kernel.org/r/20230111200136.1851322-1-Liam.Howlett@oracle.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216911
Fixes: 54a611b6 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: <amanieu@gmail.com>
  Link: https://lore.kernel.org/linux-mm/0b9f5425-08d4-8013-aa4c-e620c3b10bb2@leemhuis.info/Tested-by: Holger Hoffsttte <holger@applied-asynchrony.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

When use tools/testing/selftests/kselftest_install.sh to make the
kselftest-list.txt under tools/testing/selftests/kselftest_install.

Then use tools/testing/selftests/kselftest_install/run_kselftest.sh to run
all the kselftests in kselftest-list.txt, it will be blocked by case
"filesystems/fat: run_fat_tests.sh" with "Warning: file run_fat_tests.sh
is not executable", so grant executable permission to run_fat_tests.sh to
fix this issue.

Link: https://lkml.kernel.org/r/dfdbba6df8a1ab34bb1e81cd8bd7ca3f9ed5c369.1673424747.git.pengfei.xu@intel.com
Fixes: dd7c9be3 ("selftests/filesystems: add a vfat RENAME_EXCHANGE test")
Signed-off-by: Pengfei Xu <pengfei.xu@intel.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

__USE_GNU should be an internal macro only used inside glibc.  Either
memfd_create() or fallocate() requires _GNU_SOURCE per man page, where
__USE_GNU will further be defined by glibc headers include/features.h:

  #ifdef _GNU_SOURCE
  # define __USE_GNU	1
  #endif

This fixes:

   >> hugetlb-madvise.c:20: warning: "__USE_GNU" redefined
      20 | #define __USE_GNU
         |
   In file included from /usr/include/x86_64-linux-gnu/bits/libc-header-start.h:33,
                    from /usr/include/stdlib.h:26,
                    from hugetlb-madvise.c:16:
   /usr/include/features.h:407: note: this is the location of the previous definition
     407 | # define __USE_GNU      1
         |

Link: https://lkml.kernel.org/r/Y8V9z+z6Tk7NetI3@x1nSigned-off-by: Peter Xu <peterx@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

This patch should harden commit 15520a3f ("mm: use pte markers for
swap errors") on using pte markers for swapin errors on a few corner
cases.

1. Propagate swapin errors across fork()s: if there're swapin errors in
   the parent mm, after fork()s the child should sigbus too when an error
   page is accessed.

2. Fix a rare condition race in pte_marker_clear() where a uffd-wp pte
   marker can be quickly switched to a swapin error.

3. Explicitly ignore swapin error pte markers in change_protection().

I mostly don't worry on (2) or (3) at all, but we should still have them. 
Case (1) is special because it can potentially cause silent data corrupt
on child when parent has swapin error triggered with swapoff, but since
swapin error is rare itself already it's probably not easy to trigger
either.

Currently there is a priority difference between the uffd-wp bit and the
swapin error entry, in which the swapin error always has higher priority
(e.g.  we don't need to wr-protect a swapin error pte marker).

If there will be a 3rd bit introduced, we'll probably need to consider a
more involved approach so we may need to start operate on the bits.  Let's
leave that for later.

This patch is tested with case (1) explicitly where we'll get corrupted
data before in the child if there's existing swapin error pte markers, and
after patch applied the child can be rightfully killed.

We don't need to copy stable for this one since 15520a3f just landed
as part of v6.2-rc1, only "Fixes" applied.

Link: https://lkml.kernel.org/r/20221214200453.1772655-3-peterx@redhat.com
Fixes: 15520a3f ("mm: use pte markers for swap errors")
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Pengfei Xu <pengfei.xu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "mm: Fixes on pte markers".

Patch 1 resolves the syzkiller report from Pengfei.

Patch 2 further harden pte markers when used with the recent swapin error
markers.  The major case is we should persist a swapin error marker after
fork(), so child shouldn't read a corrupted page.


This patch (of 2):

When fork(), dst_vma is not guaranteed to have VM_UFFD_WP even if src may
have it and has pte marker installed.  The warning is improper along with
the comment.  The right thing is to inherit the pte marker when needed, or
keep the dst pte empty.

A vague guess is this happened by an accident when there's the prior patch
to introduce src/dst vma into this helper during the uffd-wp feature got
developed and I probably messed up in the rebase, since if we replace
dst_vma with src_vma the warning & comment it all makes sense too.

Hugetlb did exactly the right here (copy_hugetlb_page_range()).  Fix the
general path.

Reproducer:

https://github.com/xupengfe/syzkaller_logs/blob/main/221208_115556_copy_page_range/repro.c

Bugzilla report: https://bugzilla.kernel.org/show_bug.cgi?id=216808

Link: https://lkml.kernel.org/r/20221214200453.1772655-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20221214200453.1772655-2-peterx@redhat.com
Fixes: c56d1b62 ("mm/shmem: handle uffd-wp during fork()")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: <stable@vger.kernel.org> # 5.19+
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Merge branch 'master' into mm-hotfixes-stable

Pull x86 fixes from Borislav Petkov:

 - Make sure the poking PGD is pinned for Xen PV as it requires it this
   way

 - Fixes for two resctrl races when moving a task or creating a new
   monitoring group

 - Fix SEV-SNP guests running under HyperV where MTRRs are disabled to
   not return a UC- type mapping type on memremap() and thus cause a
   serious slowdown

 - Fix insn mnemonics in bioscall.S now that binutils is starting to fix
   confusing insn suffixes

* tag 'x86_urgent_for_v6.2_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: fix poking_init() for Xen PV guests
  x86/resctrl: Fix event counts regression in reused RMIDs
  x86/resctrl: Fix task CLOSID/RMID update race
  x86/pat: Fix pat_x_mtrr_type() for MTRR disabled case
  x86/boot: Avoid using Intel mnemonics in AT&T syntax asm

Pull EDAC fixes from Borislav Petkov:

 - Fix the EDAC device's confusion in the polling setting units

 - Fix a memory leak in highbank's probing function

* tag 'edac_urgent_for_v6.2_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras:
  EDAC/highbank: Fix memory leak in highbank_mc_probe()
  EDAC/device: Fix period calculation in edac_device_reset_delay_period()

Pull powerpc fixes from Michael Ellerman:

 - Fix a build failure with some versions of ld that have an odd version
   string

 - Fix incorrect use of mutex in the IMC PMU driver

Thanks to Kajol Jain, Michael Petlan, Ojaswin Mujoo, Peter Zijlstra, and
Yang Yingliang.

* tag 'powerpc-6.2-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64s/hash: Make stress_hpt_timer_fn() static
  powerpc/imc-pmu: Fix use of mutex in IRQs disabled section
  powerpc/boot: Fix incorrect version calculation issue in ld_version

Pull iommu fixes from Joerg Roedel:

 - Core: Fix an iommu-group refcount leak

 - Fix overflow issue in IOVA alloc path

 - ARM-SMMU fixes from Will:
    - Fix VFIO regression on NXP SoCs by reporting IOMMU_CAP_CACHE_COHERENCY
    - Fix SMMU shutdown paths to avoid device unregistration race

 - Error handling fix for Mediatek IOMMU driver

* tag 'iommu-fixes-v6.2-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/mediatek-v1: Fix an error handling path in mtk_iommu_v1_probe()
  iommu/iova: Fix alloc iova overflows issue
  iommu: Fix refcount leak in iommu_device_claim_dma_owner
  iommu/arm-smmu-v3: Don't unregister on shutdown
  iommu/arm-smmu: Don't unregister on shutdown
  iommu/arm-smmu: Report IOMMU_CAP_CACHE_COHERENCY even betterer

Pull memblock fix from Mike Rapoport:
 "memblock: always release pages to the buddy allocator in
  memblock_free_late()

  If CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled, memblock_free_pages()
  only releases pages to the buddy allocator if they are not in the
  deferred range. This is correct for free pages (as defined by
  for_each_free_mem_pfn_range_in_zone()) because free pages in the
  deferred range will be initialized and released as part of the
  deferred init process.

  memblock_free_pages() is called by memblock_free_late(), which is used
  to free reserved ranges after memblock_free_all() has run. All pages
  in reserved ranges have been initialized at that point, and
  accordingly, those pages are not touched by the deferred init process.

  This means that currently, if the pages that memblock_free_late()
  intends to release are in the deferred range, they will never be
  released to the buddy allocator. They will forever be reserved.

  In addition, memblock_free_pages() calls kmsan_memblock_free_pages(),
  which is also correct for free pages but is not correct for reserved
  pages. KMSAN metadata for reserved pages is initialized by
  kmsan_init_shadow(), which runs shortly before memblock_free_all().

  For both of these reasons, memblock_free_pages() should only be called
  for free pages, and memblock_free_late() should call
  __free_pages_core() directly instead.

  One case where this issue can occur in the wild is EFI boot on x86_64.
  The x86 EFI code reserves all EFI boot services memory ranges via
  memblock_reserve() and frees them later via memblock_free_late()
  (efi_reserve_boot_services() and efi_free_boot_services(),
  respectively).

  If any of those ranges happens to fall within the deferred init range,
  the pages will not be released and that memory will be unavailable.

  For example, on an Amazon EC2 t3.micro VM (1 GB) booting via EFI:

    v6.2-rc2:
    Node 0, zone      DMA
          spanned  4095
          present  3999
          managed  3840
    Node 0, zone    DMA32
          spanned  246652
          present  245868
          managed  178867

    v6.2-rc2 + patch:
    Node 0, zone      DMA
          spanned  4095
          present  3999
          managed  3840
    Node 0, zone    DMA32
          spanned  246652
          present  245868
          managed  222816   # +43,949 pages"

* tag 'fixes-2023-01-14' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
  mm: Always release pages to the buddy allocator in memblock_free_late().

Pull kernel hardening fixes from Kees Cook:

 - Fix CFI hash randomization with KASAN (Sami Tolvanen)

 - Check size of coreboot table entry and use flex-array

* tag 'hardening-v6.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  kbuild: Fix CFI hash randomization with KASAN
  firmware: coreboot: Check size of table entry and use flex-array

Pull module fix from Luis Chamberlain:
 "Just one fix for modules by Nick"

* tag 'modules-6.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
  kallsyms: Fix scheduling with interrupts disabled in self-test

Pull cifs fixes from Steve French:

 - memory leak and double free fix

 - two symlink fixes

 - minor cleanup fix

 - two smb1 fixes

* tag '6.2-rc3-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: Fix uninitialized memory read for smb311 posix symlink create
  cifs: fix potential memory leaks in session setup
  cifs: do not query ifaces on smb1 mounts
  cifs: fix double free on failed kerberos auth
  cifs: remove redundant assignment to the variable match
  cifs: fix file info setting in cifs_open_file()
  cifs: fix file info setting in cifs_query_path_info()

Pull SCSI fixes from James Bottomley:
 "Two minor fixes in the hisi_sas driver which only impact enterprise
  style multi-expander and shared disk situations and no core changes"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: hisi_sas: Set a port invalid only if there are no devices attached when refreshing port id
  scsi: hisi_sas: Use abort task set to reset SAS disks when discovered

Pull ATA fix from Damien Le Moal:
 "A single fix to prevent building the pata_cs5535 driver with user mode
  linux as it uses msr operations that are not defined with UML"

* tag 'ata-6.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/libata:
  ata: pata_cs5535: Don't build on UML

Pull block fixes from Jens Axboe:
 "Nothing major in here, just a collection of NVMe fixes and dropping a
  wrong might_sleep() that static checkers tripped over but which isn't
  valid"

* tag 'block-6.2-2023-01-13' of git://git.kernel.dk/linux:
  MAINTAINERS: stop nvme matching for nvmem files
  nvme: don't allow unprivileged passthrough on partitions
  nvme: replace the "bool vec" arguments with flags in the ioctl path
  nvme: remove __nvme_ioctl
  nvme-pci: fix error handling in nvme_pci_enable()
  nvme-pci: add NVME_QUIRK_IDENTIFY_CNS quirk to Apple T2 controllers
  nvme-apple: add NVME_QUIRK_IDENTIFY_CNS quirk to fix regression
  block: Drop spurious might_sleep() from blk_put_queue()

Pull io_uring fixes from Jens Axboe:
 "A fix for a regression that happened last week, rest is fixes that
  will be headed to stable as well. In detail:

   - Fix for a regression added with the leak fix from last week (me)

   - In writing a test case for that leak, inadvertently discovered a
     case where we a poll request can race. So fix that up and mark it
     for stable, and also ensure that fdinfo covers both the poll tables
     that we have. The latter was an oversight when the split poll table
     were added (me)

   - Fix for a lockdep reported issue with IOPOLL (Pavel)"

* tag 'io_uring-6.2-2023-01-13' of git://git.kernel.dk/linux:
  io_uring: lock overflowing for IOPOLL
  io_uring/poll: attempt request issue after racy poll wakeup
  io_uring/fdinfo: include locked hash table in fdinfo output
  io_uring/poll: add hash if ready poll request can't complete inline
  io_uring/io-wq: only free worker if it was allocated for creation

Pull pci fixes from Bjorn Helgaas:

 - Work around apparent firmware issue that made Linux reject MMCONFIG
   space, which broke PCI extended config space (Bjorn Helgaas)

 - Fix CONFIG_PCIE_BT1 dependency due to mid-air collision between a
   PCI_MSI_IRQ_DOMAIN -> PCI_MSI change and addition of PCIE_BT1 (Lukas
   Bulwahn)

* tag 'pci-v6.2-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  x86/pci: Treat EfiMemoryMappedIO as reservation of ECAM space
  x86/pci: Simplify is_mmconf_reserved() messages
  PCI: dwc: Adjust to recent removal of PCI_MSI_IRQ_DOMAIN

Clang emits a asan.module_ctor constructor to each object file
when KASAN is enabled, and these functions are indirectly called
in do_ctors. With CONFIG_CFI_CLANG, the compiler also emits a CFI
type hash before each address-taken global function so they can
pass indirect call checks.

However, in commit 0c3e806e ("x86/cfi: Add boot time hash
randomization"), x86 implemented boot time hash randomization,
which relies on the .cfi_sites section generated by objtool. As
objtool is run against vmlinux.o instead of individual object
files with X86_KERNEL_IBT (enabled by default), CFI types in
object files that are not part of vmlinux.o end up not being
included in .cfi_sites, and thus won't get randomized and trip
CFI when called.

Only .vmlinux.export.o and init/version-timestamp.o are linked
into vmlinux separately from vmlinux.o. As these files don't
contain any functions, disable KASAN for both of them to avoid
breaking hash randomization.

Link: https://github.com/ClangBuiltLinux/linux/issues/1742
Fixes: 0c3e806e ("x86/cfi: Add boot time hash randomization")
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230112224948.1479453-2-samitolvanen@google.com

The memcpy() of the data following a coreboot_table_entry couldn't
be evaluated by the compiler under CONFIG_FORTIFY_SOURCE. To make it
easier to reason about, add an explicit flexible array member to struct
coreboot_device so the entire entry can be copied at once. Additionally,
validate the sizes before copying. Avoids this run-time false positive
warning:

  memcpy: detected field-spanning write (size 168) of single field "&device->entry" at drivers/firmware/google/coreboot_table.c:103 (size 8)
Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Link: https://lore.kernel.org/all/03ae2704-8c30-f9f0-215b-7cdf4ad35a9a@molgen.mpg.de/
Cc: Jack Rosenthal <jrosenth@chromium.org>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Julius Werner <jwerner@chromium.org>
Cc: Brian Norris <briannorris@chromium.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/20230107031406.gonna.761-kees@kernel.orgReviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Link: https://lore.kernel.org/r/20230112230312.give.446-kees@kernel.org

kallsyms_on_each* may schedule so must not be called with interrupts
disabled. The iteration function could disable interrupts, but this
also changes lookup_symbol() to match the change to the other timing
code.
Reported-by: Erhard F. <erhard_f@mailbox.org>
Link: https://lore.kernel.org/all/bug-216902-206035@https.bugzilla.kernel.org%2F/Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/oe-lkp/202212251728.8d0872ff-oliver.sang@intel.com
Fixes: 30f3bb09 ("kallsyms: Add self-test facility")
Tested-by: "Erhard F." <erhard_f@mailbox.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

This driver uses MSR functions that aren't implemented under UML.
Avoid building it to prevent tripping up allyesconfig.

e.g.
/usr/lib/gcc/x86_64-pc-linux-gnu/12/../../../../x86_64-pc-linux-gnu/bin/ld: pata_cs5535.c:(.text+0x3a3): undefined reference to `__tracepoint_read_msr'
/usr/lib/gcc/x86_64-pc-linux-gnu/12/../../../../x86_64-pc-linux-gnu/bin/ld: pata_cs5535.c:(.text+0x3d2): undefined reference to `__tracepoint_write_msr'
/usr/lib/gcc/x86_64-pc-linux-gnu/12/../../../../x86_64-pc-linux-gnu/bin/ld: pata_cs5535.c:(.text+0x457): undefined reference to `__tracepoint_write_msr'
/usr/lib/gcc/x86_64-pc-linux-gnu/12/../../../../x86_64-pc-linux-gnu/bin/ld: pata_cs5535.c:(.text+0x481): undefined reference to `do_trace_write_msr'
/usr/lib/gcc/x86_64-pc-linux-gnu/12/../../../../x86_64-pc-linux-gnu/bin/ld: pata_cs5535.c:(.text+0x4d5): undefined reference to `do_trace_write_msr'
/usr/lib/gcc/x86_64-pc-linux-gnu/12/../../../../x86_64-pc-linux-gnu/bin/ld: pata_cs5535.c:(.text+0x4f5): undefined reference to `do_trace_read_msr'
/usr/lib/gcc/x86_64-pc-linux-gnu/12/../../../../x86_64-pc-linux-gnu/bin/ld: pata_cs5535.c:(.text+0x51c): undefined reference to `do_trace_write_msr'
Signed-off-by: Peter Foley <pefoley2@pefoley.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>

Pull kvm fixes from Paolo Bonzini:
 "ARM:

   - Fix the PMCR_EL0 reset value after the PMU rework

   - Correctly handle S2 fault triggered by a S1 page table walk by not
     always classifying it as a write, as this breaks on R/O memslots

   - Document why we cannot exit with KVM_EXIT_MMIO when taking a write
     fault from a S1 PTW on a R/O memslot

   - Put the Apple M2 on the naughty list for not being able to
     correctly implement the vgic SEIS feature, just like the M1 before
     it

   - Reviewer updates: Alex is stepping down, replaced by Zenghui

  x86:

   - Fix various rare locking issues in Xen emulation and teach lockdep
     to detect them

   - Documentation improvements

   - Do not return host topology information from KVM_GET_SUPPORTED_CPUID"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86/xen: Avoid deadlock by adding kvm->arch.xen.xen_lock leaf node lock
  KVM: Ensure lockdep knows about kvm->lock vs. vcpu->mutex ordering rule
  KVM: x86/xen: Fix potential deadlock in kvm_xen_update_runstate_guest()
  KVM: x86/xen: Fix lockdep warning on "recursive" gpc locking
  Documentation: kvm: fix SRCU locking order docs
  KVM: x86: Do not return host topology information from KVM_GET_SUPPORTED_CPUID
  KVM: nSVM: clarify recalc_intercepts() wrt CR8
  MAINTAINERS: Remove myself as a KVM/arm64 reviewer
  MAINTAINERS: Add Zenghui Yu as a KVM/arm64 reviewer
  KVM: arm64: vgic: Add Apple M2 cpus to the list of broken SEIS implementations
  KVM: arm64: Convert FSC_* over to ESR_ELx_FSC_*
  KVM: arm64: Document the behaviour of S1PTW faults on RO memslots
  KVM: arm64: Fix S1PTW handling on RO memslots
  KVM: arm64: PMU: Fix PMCR_EL0 reset value

On the x86-64 architecture even a failing cmpxchg grants exclusive
access to the cacheline, making it preferable to retry the failed op
immediately instead of stalling with the pause instruction.

To illustrate the impact, below are benchmark results obtained by
running various will-it-scale tests on top of the 6.2-rc3 kernel and
Cascade Lake (2 sockets * 24 cores * 2 threads) CPU.

All results in ops/s.  Note there is some variance in re-runs, but the
code is consistently faster when contention is present.

  open3 ("Same file open/close"):
  proc          stock       no-pause
     1         805603         814942       (+%1)
     2        1054980        1054781       (-0%)
     8        1544802        1822858      (+18%)
    24        1191064        2199665      (+84%)
    48         851582        1469860      (+72%)
    96         609481        1427170     (+134%)

  fstat2 ("Same file fstat"):
  proc          stock       no-pause
     1        3013872        3047636       (+1%)
     2        4284687        4400421       (+2%)
     8        3257721        5530156      (+69%)
    24        2239819        5466127     (+144%)
    48        1701072        5256609     (+209%)
    96        1269157        6649326     (+423%)

Additionally, a kernel with a private patch to help access() scalability:
access2 ("Same file access"):

  proc          stock        patched      patched
                                         +nopause
    24        2378041        2005501      5370335  (-15% / +125%)

That is, fixing the problems in access itself *reduces* scalability
after the cacheline ping-pong only happens in lockref with the pause
instruction.

Note that fstat and access benchmarks are not currently integrated into
will-it-scale, but interested parties can find them in pull requests to
said project.

Code at hand has a rather tortured history.  First modification showed
up in commit d472d9d9 ("lockref: Relax in cmpxchg loop"), written
with Itanium in mind.  Later it got patched up to use an arch-dependent
macro to stop doing it on s390 where it caused a significant regression.
Said macro had undergone revisions and was ultimately eliminated later,
going back to cpu_relax.

While I intended to only remove cpu_relax for x86-64, I got the
following comment from Linus:

    I would actually prefer just removing it entirely and see if
    somebody else hollers. You have the numbers to prove it hurts on
    real hardware, and I don't think we have any numbers to the
    contrary.

    So I think it's better to trust the numbers and remove it as a
    failure, than say "let's just remove it on x86-64 and leave
    everybody else with the potentially broken code"

Additionally, Will Deacon (maintainer of the arm64 port, one of the
architectures previously benchmarked):

    So, from the arm64 side of the fence, I'm perfectly happy just
    removing the cpu_relax() calls from lockref.

As such, come back full circle in history and whack it altogether.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/all/CAGudoHHx0Nqg6DE70zAVA75eV-HXfWyhVMWZ-aSeOofkA_=WdA@mail.gmail.com/
Acked-by: Tony Luck <tony.luck@intel.com> # ia64
Acked-by: Nicholas Piggin <npiggin@gmail.com> # powerpc
Acked-by: Will Deacon <will@kernel.org> # arm64
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Normally we reject ECAM space unless it is reported as reserved in the E820
table or via a PNP0C02 _CRS method (PCI Firmware, r3.3, sec 4.1.2).

07eab090 ("efi/x86: Remove EfiMemoryMappedIO from E820 map"), removes
E820 entries that correspond to EfiMemoryMappedIO regions because some
other firmware uses EfiMemoryMappedIO for PCI host bridge windows, and the
E820 entries prevent Linux from allocating BAR space for hot-added devices.

Some firmware doesn't report ECAM space via PNP0C02 _CRS methods, but does
mention it as an EfiMemoryMappedIO region via EFI GetMemoryMap(), which is
normally converted to an E820 entry by a bootloader or EFI stub.  After
07eab090, that E820 entry is removed, so we reject this ECAM space,
which makes PCI extended config space (offsets 0x100-0xfff) inaccessible.

The lack of extended config space breaks anything that relies on it,
including perf, VSEC telemetry, EDAC, QAT, SR-IOV, etc.

Allow use of ECAM for extended config space when the region is covered by
an EfiMemoryMappedIO region, even if it's not included in E820 or PNP0C02
_CRS.

Link: https://lore.kernel.org/r/ac2693d8-8ba3-72e0-5b66-b3ae008d539d@linux.intel.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216891
Fixes: 07eab090 ("efi/x86: Remove EfiMemoryMappedIO from E820 map")
Link: https://lore.kernel.org/r/20230110180243.1590045-3-helgaas@kernel.orgReported-by: Kan Liang <kan.liang@linux.intel.com>
Reported-by: Tony Luck <tony.luck@intel.com>
Reported-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reported-by: Yunying Sun <yunying.sun@intel.com>
Reported-by: Baowen Zheng <baowen.zheng@corigine.com>
Reported-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reported-by: Yang Lixiao <lixiao.yang@intel.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Tested-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Tested-by: Yunying Sun <yunying.sun@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>