When booted through startup_64(), the kernel keeps running on the EFI
page table until the KASLR code sets up its own page table. Without
KASLR, the pre-decompression boot code never switches off the EFI page
table. Change that by unconditionally switching to a kernel-controlled
page table after relocation.

This makes sure the kernel can make changes to the mapping when
necessary, for example map pages unencrypted in SEV and SEV-ES guests.

Also, remove the debug_putstr() calls in initialize_identity_maps()
because the function now runs before console_init() is called.

 [ bp: Massage commit message. ]
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NKees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-17-joro@8bytes.org

Install a page-fault handler to add an identity mapping to addresses
not yet mapped. Also do some checking whether the error code is sane.

This makes non SEV-ES machines use the exception handling
infrastructure in the pre-decompressions boot code too, making it less
likely to break in the future.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NKees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-16-joro@8bytes.org

The file contains only code related to identity-mapped page tables.
Rename the file and compile it always in.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NKees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-15-joro@8bytes.org

Add code needed to setup an IDT in the early pre-decompression
boot-code. The IDT is loaded first in startup_64, which is after
EfiExitBootServices() has been called, and later reloaded when the
kernel image has been relocated to the end of the decompression area.

This allows to setup different IDT handlers before and after the
relocation.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-14-joro@8bytes.org

The x86-64 ABI defines a red-zone on the stack:

  The 128-byte area beyond the location pointed to by %rsp is considered
  to be reserved and shall not be modified by signal or interrupt
  handlers. Therefore, functions may use this area for temporary data
  that is not needed across function calls. In particular, leaf
  functions may use this area for their entire stack frame, rather than
  adjusting the stack pointer in the prologue and epilogue. This area is
  known as the red zone.

This is not compatible with exception handling, because the IRET frame
written by the hardware at the stack pointer and the functions to handle
the exception will overwrite the temporary variables of the interrupted
function, causing undefined behavior. So disable red-zones for the
pre-decompression boot code.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NKees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-13-joro@8bytes.org

Add a function to check whether an instruction has a REP prefix.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NMasami Hiramatsu <mhiramat@kernel.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-12-joro@8bytes.org

Add a function to the instruction decoder which returns the pt_regs
offset of the register specified in the reg field of the modrm byte.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NMasami Hiramatsu <mhiramat@kernel.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-11-joro@8bytes.org

Factor out the code used to decode an instruction with the correct
address and operand sizes to a helper function.

No functional changes.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-10-joro@8bytes.org

Factor out the code to fetch the instruction from user-space to a helper
function.

No functional changes.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-9-joro@8bytes.org

The inat-tables.c file has some arrays in it that contain pointers to
other arrays. These pointers need to be relocated when the kernel
image is moved to a different location.

The pre-decompression boot-code has no support for applying ELF
relocations, so initialize these arrays at runtime in the
pre-decompression code to make sure all pointers are correctly
initialized.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NMasami Hiramatsu <mhiramat@kernel.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-8-joro@8bytes.org

Move the definition of the x86 page-fault error code bits to a new
header file asm/trap_pf.h. This makes it easier to include them into
pre-decompression boot code. No functional changes.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-7-joro@8bytes.org

Add CPU feature detection for Secure Encrypted Virtualization with
Encrypted State. This feature enhances SEV by also encrypting the
guest register state, making it in-accessible to the hypervisor.
Signed-off-by: NTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-6-joro@8bytes.org

Use the shorthand to make it more readable.

No functional changes.
Signed-off-by: NBorislav Petkov <bp@alien8.de>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-5-joro@8bytes.org

Building a correct GHCB for the hypervisor requires setting valid bits
in the GHCB. Simplify that process by providing accessor functions to
set values and to update the valid bitmap and to check the valid bitmap
in KVM.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-4-joro@8bytes.org

Extend the vmcb_safe_area with SEV-ES fields and add a new
'struct ghcb' which will be used for guest-hypervisor communication.
Signed-off-by: NTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-3-joro@8bytes.org

Do not allocate a vmcb_control_area and a vmcb_save_area on the stack,
as these structures will become larger with future extenstions of
SVM and thus the svm_set_nested_state() function will become a too large
stack frame.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-2-joro@8bytes.org

Pick up work happening in parallel to avoid nasty merge conflicts later.
Signed-off-by: NBorislav Petkov <bp@suse.de>

Signed-off-by: NBorislav Petkov <bp@suse.de>

Pull more io_uring fixes from Jens Axboe:
 "Two followup fixes. One is fixing a regression from this merge window,
  the other is two commits fixing cancelation of deferred requests.

  Both have gone through full testing, and both spawned a few new
  regression test additions to liburing.

   - Don't play games with const, properly store the output iovec and
     assign it as needed.

   - Deferred request cancelation fix (Pavel)"

* tag 'io_uring-5.9-2020-09-06' of git://git.kernel.dk/linux-block:
  io_uring: fix linked deferred ->files cancellation
  io_uring: fix cancel of deferred reqs with ->files
  io_uring: fix explicit async read/write mapping for large segments

Pull iommu fixes from Joerg Roedel:

 - three Intel VT-d fixes to fix address handling on 32bit, fix a NULL
   pointer dereference bug and serialize a hardware register access as
   required by the VT-d spec.

 - two patches for AMD IOMMU to force AMD GPUs into translation mode
   when memory encryption is active and disallow using IOMMUv2
   functionality.  This makes the AMDGPU driver work when memory
   encryption is active.

 - two more fixes for AMD IOMMU to fix updating the Interrupt Remapping
   Table Entries.

 - MAINTAINERS file update for the Qualcom IOMMU driver.

* tag 'iommu-fixes-v5.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/vt-d: Handle 36bit addressing for x86-32
  iommu/amd: Do not use IOMMUv2 functionality when SME is active
  iommu/amd: Do not force direct mapping when SME is active
  iommu/amd: Use cmpxchg_double() when updating 128-bit IRTE
  iommu/amd: Restore IRTE.RemapEn bit after programming IRTE
  iommu/vt-d: Fix NULL pointer dereference in dev_iommu_priv_set()
  iommu/vt-d: Serialize IOMMU GCMD register modifications
  MAINTAINERS: Update QUALCOMM IOMMU after Arm SMMU drivers move

Pull x86 fixes from Ingo Molnar:

 - more generic entry code ABI fallout

 - debug register handling bugfixes

 - fix vmalloc mappings on 32-bit kernels

 - kprobes instrumentation output fix on 32-bit kernels

 - fix over-eager WARN_ON_ONCE() on !SMAP hardware

 - NUMA debugging fix

 - fix Clang related crash on !RETPOLINE kernels

* tag 'x86-urgent-2020-09-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/entry: Unbreak 32bit fast syscall
  x86/debug: Allow a single level of #DB recursion
  x86/entry: Fix AC assertion
  tracing/kprobes, x86/ptrace: Fix regs argument order for i386
  x86, fakenuma: Fix invalid starting node ID
  x86/mm/32: Bring back vmalloc faulting on x86_32
  x86/cmdline: Disable jump tables for cmdline.c

Pull xen updates from Juergen Gross:
 "A small series for fixing a problem with Xen PVH guests when running
  as backends (e.g. as dom0).

  Mapping other guests' memory is now working via ZONE_DEVICE, thus not
  requiring to abuse the memory hotplug functionality for that purpose"

* tag 'for-linus-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: add helpers to allocate unpopulated memory
  memremap: rename MEMORY_DEVICE_DEVDAX to MEMORY_DEVICE_GENERIC
  xen/balloon: add header guard

While looking for ->files in ->defer_list, consider that requests there
may actually be links.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

While trying to cancel requests with ->files, it also should look for
requests in ->defer_list, otherwise it might end up hanging a thread.

Cancel all requests in ->defer_list up to the last request there with
matching ->files, that's needed to follow drain ordering semantics.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Merge tags 'auxdisplay-for-linus-v5.9-rc4', 'clang-format-for-linus-v5.9-rc4' and 'compiler-attributes-for-linus-v5.9-rc4' of git://github.com/ojeda/linux

Pull misc fixes from Miguel Ojeda:
 "A trivial patch for auxdisplay:

   - Replace HTTP links with HTTPS ones (Alexander A. Klimov)

  The usual clang-format trivial update:

   - Update with the latest for_each macro list (Miguel Ojeda)

  And Luc requested me to pick a sparse fix on my queue, so here it goes
  along with other two trivial Compiler Attributes ones (also from Luc).

   - sparse: use static inline for __chk_{user,io}_ptr() (Luc Van
     Oostenryck)

   - Compiler Attributes: fix comment concerning GCC 4.6 (Luc Van
     Oostenryck)

   - Compiler Attributes: remove comment about sparse not supporting
     __has_attribute (Luc Van Oostenryck)"

* tag 'auxdisplay-for-linus-v5.9-rc4' of git://github.com/ojeda/linux:
  auxdisplay: Replace HTTP links with HTTPS ones

* tag 'clang-format-for-linus-v5.9-rc4' of git://github.com/ojeda/linux:
  clang-format: Update with the latest for_each macro list

* tag 'compiler-attributes-for-linus-v5.9-rc4' of git://github.com/ojeda/linux:
  sparse: use static inline for __chk_{user,io}_ptr()
  Compiler Attributes: fix comment concerning GCC 4.6
  Compiler Attributes: remove comment about sparse not supporting __has_attribute

Pull ARC fixes from Vineet Gupta:

 - HSDK-4xd Dev system: perf driver updates for sampling interrupt

 - HSDK* Dev System: Ethernet broken [Evgeniy Didin]

 - HIGHMEM broken (2 memory banks) [Mike Rapoport]

 - show_regs() rewrite once and for all

 - Other minor fixes

* tag 'arc-5.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: [plat-hsdk]: Switch ethernet phy-mode to rgmii-id
  arc: fix memory initialization for systems with two memory banks
  irqchip/eznps: Fix build error for !ARC700 builds
  ARC: show_regs: fix r12 printing and simplify
  ARC: HSDK: wireup perf irq
  ARC: perf: don't bail setup if pct irq missing in device-tree
  ARC: pgalloc.h: delete a duplicated word + other fixes

Merge misc fixes from Andrew Morton:
 "19 patches.

  Subsystems affected by this patch series: MAINTAINERS, ipc, fork,
  checkpatch, lib, and mm (memcg, slub, pagemap, madvise, migration,
  hugetlb)"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  include/linux/log2.h: add missing () around n in roundup_pow_of_two()
  mm/khugepaged.c: fix khugepaged's request size in collapse_file
  mm/hugetlb: fix a race between hugetlb sysctl handlers
  mm/hugetlb: try preferred node first when alloc gigantic page from cma
  mm/migrate: preserve soft dirty in remove_migration_pte()
  mm/migrate: remove unnecessary is_zone_device_page() check
  mm/rmap: fixup copying of soft dirty and uffd ptes
  mm/migrate: fixup setting UFFD_WP flag
  mm: madvise: fix vma user-after-free
  checkpatch: fix the usage of capture group ( ... )
  fork: adjust sysctl_max_threads definition to match prototype
  ipc: adjust proc_ipc_sem_dointvec definition to match prototype
  mm: track page table modifications in __apply_to_page_range()
  MAINTAINERS: IA64: mark Status as Odd Fixes only
  MAINTAINERS: add LLVM maintainers
  MAINTAINERS: update Cavium/Marvell entries
  mm: slub: fix conversion of freelist_corrupted()
  mm: memcg: fix memcg reclaim soft lockup
  memcg: fix use-after-free in uncharge_batch

Otherwise gcc generates warnings if the expression is complicated.

Fixes: 312a0c17 ("[PATCH] LOG2: Alter roundup_pow_of_two() so that it can use a ilog2() on a constant")
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/0-v1-8a2697e3c003+41165-log_brackets_jgg@nvidia.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

collapse_file() in khugepaged passes PAGE_SIZE as the number of pages to
be read to page_cache_sync_readahead().  The intent was probably to read
a single page.  Fix it to use the number of pages to the end of the
window instead.

Fixes: 99cb0dbd ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NMatthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: NSong Liu <songliubraving@fb.com>
Acked-by: NYang Shi <shy828301@gmail.com>
Acked-by: NPankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Eric Biggers <ebiggers@google.com>
Link: https://lkml.kernel.org/r/20200903140844.14194-2-willy@infradead.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is a race between the assignment of `table->data` and write value
to the pointer of `table->data` in the __do_proc_doulongvec_minmax() on
the other thread.

  CPU0:                                 CPU1:
                                        proc_sys_write
  hugetlb_sysctl_handler                  proc_sys_call_handler
  hugetlb_sysctl_handler_common             hugetlb_sysctl_handler
    table->data = &tmp;                       hugetlb_sysctl_handler_common
                                                table->data = &tmp;
      proc_doulongvec_minmax
        do_proc_doulongvec_minmax           sysctl_head_finish
          __do_proc_doulongvec_minmax         unuse_table
            i = table->data;
            *i = val;  // corrupt CPU1's stack

Fix this by duplicating the `table`, and only update the duplicate of
it.  And introduce a helper of proc_hugetlb_doulongvec_minmax() to
simplify the code.

The following oops was seen:

    BUG: kernel NULL pointer dereference, address: 0000000000000000
    #PF: supervisor instruction fetch in kernel mode
    #PF: error_code(0x0010) - not-present page
    Code: Bad RIP value.
    ...
    Call Trace:
     ? set_max_huge_pages+0x3da/0x4f0
     ? alloc_pool_huge_page+0x150/0x150
     ? proc_doulongvec_minmax+0x46/0x60
     ? hugetlb_sysctl_handler_common+0x1c7/0x200
     ? nr_hugepages_store+0x20/0x20
     ? copy_fd_bitmaps+0x170/0x170
     ? hugetlb_sysctl_handler+0x1e/0x20
     ? proc_sys_call_handler+0x2f1/0x300
     ? unregister_sysctl_table+0xb0/0xb0
     ? __fd_install+0x78/0x100
     ? proc_sys_write+0x14/0x20
     ? __vfs_write+0x4d/0x90
     ? vfs_write+0xef/0x240
     ? ksys_write+0xc0/0x160
     ? __ia32_sys_read+0x50/0x50
     ? __close_fd+0x129/0x150
     ? __x64_sys_write+0x43/0x50
     ? do_syscall_64+0x6c/0x200
     ? entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: e5ff2159 ("hugetlb: multiple hstates for multiple page sizes")
Signed-off-by: NMuchun Song <songmuchun@bytedance.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20200828031146.43035-1-songmuchun@bytedance.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since commit cf11e85f ("mm: hugetlb: optionally allocate gigantic
hugepages using cma"), the gigantic page would be allocated from node
which is not the preferred node, although there are pages available from
that node.  The reason is that the nid parameter has been ignored in
alloc_gigantic_page().

Besides, the __GFP_THISNODE also need be checked if user required to
alloc only from the preferred node.

After this patch, the preferred node is tried first before other allowed
nodes, and don't try to allocate from other nodes if __GFP_THISNODE is
specified.  If user don't specify the preferred node, the current node
will be used as preferred node, which makes sure consistent behavior of
allocating gigantic and non-gigantic hugetlb page.

Fixes: cf11e85f ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: NLi Xinhai <lixinhai.lxh@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Link: https://lkml.kernel.org/r/20200902025016.697260-1-lixinhai.lxh@gmail.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The code to remove a migration PTE and replace it with a device private
PTE was not copying the soft dirty bit from the migration entry.  This
could lead to page contents not being marked dirty when faulting the page
back from device private memory.
Signed-off-by: NRalph Campbell <rcampbell@nvidia.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Link: https://lkml.kernel.org/r/20200831212222.22409-3-rcampbell@nvidia.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "mm/migrate: preserve soft dirty in remove_migration_pte()".

I happened to notice this from code inspection after seeing Alistair
Popple's patch ("mm/rmap: Fixup copying of soft dirty and uffd ptes").

This patch (of 2):

The check for is_zone_device_page() and is_device_private_page() is
unnecessary since the latter is sufficient to determine if the page is a
device private page.  Simplify the code for easier reading.
Signed-off-by: NRalph Campbell <rcampbell@nvidia.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Link: https://lkml.kernel.org/r/20200831212222.22409-1-rcampbell@nvidia.com
Link: https://lkml.kernel.org/r/20200831212222.22409-2-rcampbell@nvidia.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

During memory migration a pte is temporarily replaced with a migration
swap pte.  Some pte bits from the existing mapping such as the soft-dirty
and uffd write-protect bits are preserved by copying these to the
temporary migration swap pte.

However these bits are not stored at the same location for swap and
non-swap ptes.  Therefore testing these bits requires using the
appropriate helper function for the given pte type.

Unfortunately several code locations were found where the wrong helper
function is being used to test soft_dirty and uffd_wp bits which leads to
them getting incorrectly set or cleared during page-migration.

Fix these by using the correct tests based on pte type.

Fixes: a5430dda ("mm/migrate: support un-addressable ZONE_DEVICE page in migration")
Fixes: 8c3328f1 ("mm/migrate: migrate_vma() unmap page from vma while collecting pages")
Fixes: f45ec5ff ("userfaultfd: wp: support swap and page migration")
Signed-off-by: NAlistair Popple <alistair@popple.id.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NPeter Xu <peterx@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Alistair Popple <alistair@popple.id.au>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200825064232.10023-2-alistair@popple.id.auSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit f45ec5ff ("userfaultfd: wp: support swap and page migration")
introduced support for tracking the uffd wp bit during page migration.
However the non-swap PTE variant was used to set the flag for zone device
private pages which are a type of swap page.

This leads to corruption of the swap offset if the original PTE has the
uffd_wp flag set.

Fixes: f45ec5ff ("userfaultfd: wp: support swap and page migration")
Signed-off-by: NAlistair Popple <alistair@popple.id.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NPeter Xu <peterx@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Link: https://lkml.kernel.org/r/20200825064232.10023-1-alistair@popple.id.auSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The syzbot reported the below use-after-free:

  BUG: KASAN: use-after-free in madvise_willneed mm/madvise.c:293 [inline]
  BUG: KASAN: use-after-free in madvise_vma mm/madvise.c:942 [inline]
  BUG: KASAN: use-after-free in do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145
  Read of size 8 at addr ffff8880a6163eb0 by task syz-executor.0/9996

  CPU: 0 PID: 9996 Comm: syz-executor.0 Not tainted 5.9.0-rc1-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Call Trace:
    __dump_stack lib/dump_stack.c:77 [inline]
    dump_stack+0x18f/0x20d lib/dump_stack.c:118
    print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
    __kasan_report mm/kasan/report.c:513 [inline]
    kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
    madvise_willneed mm/madvise.c:293 [inline]
    madvise_vma mm/madvise.c:942 [inline]
    do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145
    do_madvise mm/madvise.c:1169 [inline]
    __do_sys_madvise mm/madvise.c:1171 [inline]
    __se_sys_madvise mm/madvise.c:1169 [inline]
    __x64_sys_madvise+0xd9/0x110 mm/madvise.c:1169
    do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

  Allocated by task 9992:
    kmem_cache_alloc+0x138/0x3a0 mm/slab.c:3482
    vm_area_alloc+0x1c/0x110 kernel/fork.c:347
    mmap_region+0x8e5/0x1780 mm/mmap.c:1743
    do_mmap+0xcf9/0x11d0 mm/mmap.c:1545
    vm_mmap_pgoff+0x195/0x200 mm/util.c:506
    ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596
    do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

  Freed by task 9992:
    kmem_cache_free.part.0+0x67/0x1f0 mm/slab.c:3693
    remove_vma+0x132/0x170 mm/mmap.c:184
    remove_vma_list mm/mmap.c:2613 [inline]
    __do_munmap+0x743/0x1170 mm/mmap.c:2869
    do_munmap mm/mmap.c:2877 [inline]
    mmap_region+0x257/0x1780 mm/mmap.c:1716
    do_mmap+0xcf9/0x11d0 mm/mmap.c:1545
    vm_mmap_pgoff+0x195/0x200 mm/util.c:506
    ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596
    do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

It is because vma is accessed after releasing mmap_lock, but someone
else acquired the mmap_lock and the vma is gone.

Releasing mmap_lock after accessing vma should fix the problem.

Fixes: 692fe624 ("mm: Handle MADV_WILLNEED through vfs_fadvise()")
Reported-by: syzbot+b90df26038d1d5d85c97@syzkaller.appspotmail.com
Signed-off-by: NYang Shi <shy828301@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NJan Kara <jack@suse.cz>
Cc: <stable@vger.kernel.org>	[5.4+]
Link: https://lkml.kernel.org/r/20200816141204.162624-1-shy828301@gmail.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The usage of "capture group (...)" in the immediate condition after `&&`
results in `$1` being uninitialized.  This issues a warning "Use of
uninitialized value $1 in regexp compilation at ./scripts/checkpatch.pl
line 2638".

I noticed this bug while running checkpatch on the set of commits from
v5.7 to v5.8-rc1 of the kernel on the commits with a diff content in
their commit message.

This bug was introduced in the script by commit e518e9a5
("checkpatch: emit an error when there's a diff in a changelog").  It
has been in the script since then.

The author intended to store the match made by capture group in variable
`$1`.  This should have contained the name of the file as `[\w/]+`
matched.  However, this couldn't be accomplished due to usage of capture
group and `$1` in the same regular expression.

Fix this by placing the capture group in the condition before `&&`.
Thus, `$1` can be initialized to the text that capture group matches
thereby setting it to the desired and required value.

Fixes: e518e9a5 ("checkpatch: emit an error when there's a diff in a changelog")
Signed-off-by: NMrinal Pandey <mrinalmni@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Tested-by: NLukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: NLukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Joe Perches <joe@perches.com>
Link: https://lkml.kernel.org/r/20200714032352.f476hanaj2dlmiot@mrinalpandeySigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 32927393 ("sysctl: pass kernel pointers to ->proc_handler")
changed ctl_table.proc_handler to take a kernel pointer.  Adjust the
definition of sysctl_max_threads to match its prototype in
linux/sysctl.h which fixes the following sparse error/warning:

  kernel/fork.c:3050:47: warning: incorrect type in argument 3 (different address spaces)
  kernel/fork.c:3050:47:    expected void *
  kernel/fork.c:3050:47:    got void [noderef] __user *buffer
  kernel/fork.c:3036:5: error: symbol 'sysctl_max_threads' redeclared with different type (incompatible argument 3 (different address spaces)):
  kernel/fork.c:3036:5:    int extern [addressable] [signed] [toplevel] sysctl_max_threads( ... )
  kernel/fork.c: note: in included file (through include/linux/key.h, include/linux/cred.h, include/linux/sched/signal.h, include/linux/sched/cputime.h):
  include/linux/sysctl.h:242:5: note: previously declared as:
  include/linux/sysctl.h:242:5:    int extern [addressable] [signed] [toplevel] sysctl_max_threads( ... )

Fixes: 32927393 ("sysctl: pass kernel pointers to ->proc_handler")
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lkml.kernel.org/r/20200825093647.24263-1-tklauser@distanz.chSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 32927393 ("sysctl: pass kernel pointers to ->proc_handler")
changed ctl_table.proc_handler to take a kernel pointer.  Adjust the
signature of proc_ipc_sem_dointvec to match ctl_table.proc_handler which
fixes the following sparse error/warning:

  ipc/ipc_sysctl.c:94:47: warning: incorrect type in argument 3 (different address spaces)
  ipc/ipc_sysctl.c:94:47:    expected void *buffer
  ipc/ipc_sysctl.c:94:47:    got void [noderef] __user *buffer
  ipc/ipc_sysctl.c:194:35: warning: incorrect type in initializer (incompatible argument 3 (different address spaces))
  ipc/ipc_sysctl.c:194:35:    expected int ( [usertype] *proc_handler )( ... )
  ipc/ipc_sysctl.c:194:35:    got int ( * )( ... )

Fixes: 32927393 ("sysctl: pass kernel pointers to ->proc_handler")
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Link: https://lkml.kernel.org/r/20200825105846.5193-1-tklauser@distanz.chSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>