linux-stable.git/include/linux/mm.h, branch v5.12.8

mm/hugetlb: fix F_SEAL_FUTURE_WRITE

2021-05-19T08:56:34+00:00

commit 22247efd822e6d263f3c8bd327f3f769aea9b1d9 upstream.

Patch series "mm/hugetlb: Fix issues on file sealing and fork", v2.

Hugh reported issue with F_SEAL_FUTURE_WRITE not applied correctly to
hugetlbfs, which I can easily verify using the memfd_test program, which
seems that the program is hardly run with hugetlbfs pages (as by default
shmem).

Meanwhile I found another probably even more severe issue on that hugetlb
fork won't wr-protect child cow pages, so child can potentially write to
parent private pages.  Patch 2 addresses that.

After this series applied, "memfd_test hugetlbfs" should start to pass.

This patch (of 2):

F_SEAL_FUTURE_WRITE is missing for hugetlb starting from the first day.
There is a test program for that and it fails constantly.

$ ./memfd_test hugetlbfs
memfd-hugetlb: CREATE
memfd-hugetlb: BASIC
memfd-hugetlb: SEAL-WRITE
memfd-hugetlb: SEAL-FUTURE-WRITE
mmap() didn't fail as expected
Aborted (core dumped)

I think it's probably because no one is really running the hugetlbfs test.

Fix it by checking FUTURE_WRITE also in hugetlbfs_file_mmap() as what we
do in shmem_mmap().  Generalize a helper for that.

Link: https://lkml.kernel.org/r/20210503234356.9097-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20210503234356.9097-2-peterx@redhat.com
Fixes: ab3948f58ff84 ("mm/memfd: add an F_SEAL_FUTURE_WRITE seal to memfd")
Signed-off-by: Peter Xu 
Reported-by: Hugh Dickins 
Reviewed-by: Mike Kravetz 
Cc: Joel Fernandes (Google) 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

kasan: fix per-page tags for non-page_alloc pages

2021-03-25T16:22:55+00:00

To allow performing tag checks on page_alloc addresses obtained via
page_address(), tag-based KASAN modes store tags for page_alloc
allocations in page->flags.

Currently, the default tag value stored in page->flags is 0x00.
Therefore, page_address() returns a 0x00ffff...  address for pages that
were not allocated via page_alloc.

This might cause problems.  A particular case we encountered is a
conflict with KFENCE.  If a KFENCE-allocated slab object is being freed
via kfree(page_address(page) + offset), the address passed to kfree()
will get tagged with 0x00 (as slab pages keep the default per-page
tags).  This leads to is_kfence_address() check failing, and a KFENCE
object ending up in normal slab freelist, which causes memory
corruptions.

This patch changes the way KASAN stores tag in page-flags: they are now
stored xor'ed with 0xff.  This way, KASAN doesn't need to initialize
per-page flags for every created page, which might be slow.

With this change, page_address() returns natively-tagged (with 0xff)
pointers for pages that didn't have tags set explicitly.

This patch fixes the encountered conflict with KFENCE and prevents more
similar issues that can occur in the future.

Link: https://lkml.kernel.org/r/1a41abb11c51b264511d9e71c303bb16d5cb367b.1615475452.git.andreyknvl@google.com
Fixes: 2813b9c02962 ("kasan, mm, arm64: tag non slab memory allocated via pagealloc")
Signed-off-by: Andrey Konovalov 
Reviewed-by: Marco Elver 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Vincenzo Frascino 
Cc: Dmitry Vyukov 
Cc: Andrey Ryabinin 
Cc: Alexander Potapenko 
Cc: Peter Collingbourne 
Cc: Evgenii Stepanov 
Cc: Branislav Rankov 
Cc: Kevin Brodsky 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: introduce page_needs_cow_for_dma() for deciding whether cow

2021-03-13T19:27:30+00:00

We've got quite a few places (pte, pmd, pud) that explicitly checked
against whether we should break the cow right now during fork().  It's
easier to provide a helper, especially before we work the same thing on
hugetlbfs.

Since we'll reference is_cow_mapping() in mm.h, move it there too.
Actually it suites mm.h more since internal.h is mm/ only, but mm.h is
exported to the whole kernel.  With that we should expect another patch to
use is_cow_mapping() whenever we can across the kernel since we do use it
quite a lot but it's always done with raw code against VM_* flags.

Link: https://lkml.kernel.org/r/20210217233547.93892-4-peterx@redhat.com
Signed-off-by: Peter Xu 
Reviewed-by: Jason Gunthorpe 
Cc: Alexey Dobriyan 
Cc: Andrea Arcangeli 
Cc: Christoph Hellwig 
Cc: Daniel Vetter 
Cc: David Airlie 
Cc: David Gibson 
Cc: Gal Pressman 
Cc: Jan Kara 
Cc: Jann Horn 
Cc: Kirill Shutemov 
Cc: Kirill Tkhai 
Cc: Matthew Wilcox 
Cc: Miaohe Lin 
Cc: Mike Kravetz 
Cc: Mike Rapoport 
Cc: Roland Scheidegger 
Cc: VMware Graphics 
Cc: Wei Zhang 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/hugetlb: grab head page refcount once for group of subpages

2021-02-24T21:38:32+00:00

Patch series "mm/hugetlb: follow_hugetlb_page() improvements", v2.

While looking at ZONE_DEVICE struct page reuse particularly the last
patch[0], I found two possible improvements for follow_hugetlb_page()
which is solely used for get_user_pages()/pin_user_pages().

The first patch batches page refcount updates while the second tidies up
storing the subpages/vmas.  Both together bring the cost of slow variant
of gup() cost from ~87.6k usecs to ~5.8k usecs.

libhugetlbfs tests seem to pass as well gup_test benchmarks with hugetlbfs
vmas.

This patch (of 2):

follow_hugetlb_page() once it locks the pmd/pud, checks all its N subpages
in a huge page and grabs a reference for each one.  Similar to gup-fast,
have follow_hugetlb_page() grab the head page refcount only after counting
all its subpages that are part of the just faulted huge page.

Consequently we reduce the number of atomics necessary to pin said huge
page, which improves non-fast gup() considerably:

  - 16G with 1G huge page size
  gup_test -f /mnt/huge/file -m 16384 -r 10 -L -S -n 512 -w

PIN_LONGTERM_BENCHMARK: ~87.6k us -> ~12.8k us

Link: https://lkml.kernel.org/r/20210128182632.24562-1-joao.m.martins@oracle.com
Link: https://lkml.kernel.org/r/20210128182632.24562-2-joao.m.martins@oracle.com
Signed-off-by: Joao Martins 
Reviewed-by: Mike Kravetz 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: simplify free_highmem_page() and free_reserved_page()

2021-02-24T21:38:32+00:00

adjust_managed_page_count() as called by free_reserved_page() properly
handles pages in a highmem zone, so we can reuse it for
free_highmem_page().

We can now get rid of totalhigh_pages_inc() and simplify
free_reserved_page().

Link: https://lkml.kernel.org/r/20210126182113.19892-3-david@redhat.com
Signed-off-by: David Hildenbrand 
Reviewed-by: Oscar Salvador 
Reviewed-by: Anshuman Khandual 
Cc: Thomas Gleixner 
Cc: "Peter Zijlstra (Intel)" 
Cc: Mike Rapoport 
Cc: Michal Hocko 
Cc: Wei Yang 
Cc: "Gustavo A. R. Silva" 
Cc: Sam Ravnborg 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: simplify parater of function memmap_init_zone()

2021-02-24T21:38:31+00:00

As David suggested, simply passing 'struct zone *zone' is enough.  We can
get all needed information from 'struct zone*' easily.

Link: https://lkml.kernel.org/r/20210122135956.5946-4-bhe@redhat.com
Signed-off-by: Baoquan He 
Suggested-by: David Hildenbrand 
Reviewed-by: Mike Rapoport 
Reviewed-by: David Hildenbrand 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: rename memmap_init() and memmap_init_zone()

2021-02-24T21:38:31+00:00

The current memmap_init_zone() only handles memory region inside one zone,
actually memmap_init() does the memmap init of one zone.  So rename both
of them accordingly.

Link: https://lkml.kernel.org/r/20210122135956.5946-3-bhe@redhat.com
Signed-off-by: Baoquan He 
Reviewed-by: Mike Rapoport 
Reviewed-by: David Hildenbrand 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: fix prototype warning from kernel test robot

2021-02-24T21:38:31+00:00

Patch series "mm: clean up names and parameters of memmap_init_xxxx functions", v5.

This patchset corrects inappropriate function names of memmap_init_xxx,
and simplify parameters of functions in the code flow.  And also fix a
prototype warning reported by lkp.

This patch (of 5);

Kernel test robot calling make with 'W=1' is triggering warning like
below for memmap_init_zone() function.

  mm/page_alloc.c:6259:23: warning: no previous prototype for 'memmap_init_zone' [-Wmissing-prototypes]
   6259 | void __meminit __weak memmap_init_zone(unsigned long size, int nid,
        |                       ^~~~~~~~~~~~~~~~

Fix it by adding the function declaration in include/linux/mm.h.  Since
memmap_init_zone() has a generic version with '__weak', the declaratoin in
ia64 header file can be simply removed.

Link: https://lkml.kernel.org/r/20210122135956.5946-1-bhe@redhat.com
Link: https://lkml.kernel.org/r/20210122135956.5946-2-bhe@redhat.com
Signed-off-by: Baoquan He 
Reported-by: kernel test robot 
Reviewed-by: Mike Rapoport 
Reviewed-by: David Hildenbrand 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'topic/iomem-mmap-vs-gup-2021-02-22' of git://anongit.freedesktop.org/drm/drm

2021-02-23T01:45:02+00:00

Pull follow_pfn() updates from Daniel Vetter:
 "Fixes around VM_FPNMAP and follow_pfn:

   - replace mm/frame_vector.c by get_user_pages in misc/habana and
     drm/exynos drivers, then move that into media as it's sole user

   - close race in generic_access_phys

   - s390 pci ioctl fix of this series landed in 5.11 already

   - properly revoke iomem mappings (/dev/mem, pci files)"

* tag 'topic/iomem-mmap-vs-gup-2021-02-22' of git://anongit.freedesktop.org/drm/drm:
  PCI: Revoke mappings like devmem
  PCI: Also set up legacy files only after sysfs init
  sysfs: Support zapping of binary attr mmaps
  resource: Move devmem revoke code to resource framework
  /dev/mem: Only set filp->f_mapping
  PCI: Obey iomem restrictions for procfs mmap
  mm: Close race in generic_access_phys
  media: videobuf2: Move frame_vector into media subsystem
  mm/frame-vector: Use FOLL_LONGTERM
  misc/habana: Use FOLL_LONGTERM for userptr
  misc/habana: Stop using frame_vector helpers
  drm/exynos: Use FOLL_LONGTERM for g2d cmdlists
  drm/exynos: Stop using frame_vector helpers

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2021-02-21T21:31:43+00:00

Pull KVM updates from Paolo Bonzini:
 "x86:

   - Support for userspace to emulate Xen hypercalls

   - Raise the maximum number of user memslots

   - Scalability improvements for the new MMU.

     Instead of the complex "fast page fault" logic that is used in
     mmu.c, tdp_mmu.c uses an rwlock so that page faults are concurrent,
     but the code that can run against page faults is limited. Right now
     only page faults take the lock for reading; in the future this will
     be extended to some cases of page table destruction. I hope to
     switch the default MMU around 5.12-rc3 (some testing was delayed
     due to Chinese New Year).

   - Cleanups for MAXPHYADDR checks

   - Use static calls for vendor-specific callbacks

   - On AMD, use VMLOAD/VMSAVE to save and restore host state

   - Stop using deprecated jump label APIs

   - Workaround for AMD erratum that made nested virtualization
     unreliable

   - Support for LBR emulation in the guest

   - Support for communicating bus lock vmexits to userspace

   - Add support for SEV attestation command

   - Miscellaneous cleanups

  PPC:

   - Support for second data watchpoint on POWER10

   - Remove some complex workarounds for buggy early versions of POWER9

   - Guest entry/exit fixes

  ARM64:

   - Make the nVHE EL2 object relocatable

   - Cleanups for concurrent translation faults hitting the same page

   - Support for the standard TRNG hypervisor call

   - A bunch of small PMU/Debug fixes

   - Simplification of the early init hypercall handling

  Non-KVM changes (with acks):

   - Detection of contended rwlocks (implemented only for qrwlocks,
     because KVM only needs it for x86)

   - Allow __DISABLE_EXPORTS from assembly code

   - Provide a saner follow_pfn replacements for modules"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (192 commits)
  KVM: x86/xen: Explicitly pad struct compat_vcpu_info to 64 bytes
  KVM: selftests: Don't bother mapping GVA for Xen shinfo test
  KVM: selftests: Fix hex vs. decimal snafu in Xen test
  KVM: selftests: Fix size of memslots created by Xen tests
  KVM: selftests: Ignore recently added Xen tests' build output
  KVM: selftests: Add missing header file needed by xAPIC IPI tests
  KVM: selftests: Add operand to vmsave/vmload/vmrun in svm.c
  KVM: SVM: Make symbol 'svm_gp_erratum_intercept' static
  locking/arch: Move qrwlock.h include after qspinlock.h
  KVM: PPC: Book3S HV: Fix host radix SLB optimisation with hash guests
  KVM: PPC: Book3S HV: Ensure radix guest has no SLB entries
  KVM: PPC: Don't always report hash MMU capability for P9 < DD2.2
  KVM: PPC: Book3S HV: Save and restore FSCR in the P9 path
  KVM: PPC: remove unneeded semicolon
  KVM: PPC: Book3S HV: Use POWER9 SLBIA IH=6 variant to clear SLB
  KVM: PPC: Book3S HV: No need to clear radix host SLB before loading HPT guest
  KVM: PPC: Book3S HV: Fix radix guest SLB side channel
  KVM: PPC: Book3S HV: Remove support for running HPT guest on RPT host without mixed mode support
  KVM: PPC: Book3S HV: Introduce new capability for 2nd DAWR
  KVM: PPC: Book3S HV: Add infrastructure to support 2nd DAWR
  ...