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Peter Xu d1751118c8 mm/uffd: detect pgtable allocation failures
Before this patch, when there's any pgtable allocation issues happened
during change_protection(), the error will be ignored from the syscall. 
For shmem, there will be an error dumped into the host dmesg.  Two issues
with that:

  (1) Doing a trace dump when allocation fails is not anything close to
      grace.

  (2) The user should be notified with any kind of such error, so the user
      can trap it and decide what to do next, either by retrying, or stop
      the process properly, or anything else.

For userfault users, this will change the API of UFFDIO_WRITEPROTECT when
pgtable allocation failure happened.  It should not normally break anyone,
though.  If it breaks, then in good ways.

One man-page update will be on the way to introduce the new -ENOMEM for
UFFDIO_WRITEPROTECT.  Not marking stable so we keep the old behavior on
the 5.19-till-now kernels.

[akpm@linux-foundation.org: coding-style cleanups]
Link: https://lkml.kernel.org/r/20230104225207.1066932-4-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: James Houghton <jthoughton@google.com>
Acked-by: James Houghton <jthoughton@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-01-18 17:12:53 -08:00
arch mm/uffd: always wr-protect pte in pte|pmd_mkuffd_wp() 2023-01-18 17:12:37 -08:00
block block-6.2-2023-01-13 2023-01-13 17:41:19 -06:00
certs certs: make system keyring depend on built-in x509 parser 2022-09-24 04:31:18 +09:00
crypto This update includes the following changes: 2022-12-14 12:31:09 -08:00
Documentation mm: multi-gen LRU: rename lrugen->lists[] to lrugen->folios[] 2023-01-18 17:12:48 -08:00
drivers zram: fix typos in comments 2023-01-18 17:12:52 -08:00
fs ocfs2: use filemap_fdatawrite_wbc instead of generic_writepages 2023-01-18 17:12:51 -08:00
include mm/uffd: detect pgtable allocation failures 2023-01-18 17:12:53 -08:00
init Sync with v6.2-rc4 2023-01-18 16:52:20 -08:00
io_uring io_uring: lock overflowing for IOPOLL 2023-01-13 07:32:46 -07:00
ipc Non-MM patches for 6.2-rc1. 2022-12-12 17:28:58 -08:00
kernel mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC 2023-01-18 17:12:37 -08:00
lib maple_tree: refine mab_calc_split function 2023-01-18 17:12:47 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/uffd: detect pgtable allocation failures 2023-01-18 17:12:53 -08:00
net Including fixes from rxrpc. 2023-01-12 18:20:44 -06:00
rust rust: types: add Opaque type 2022-12-04 01:59:16 +01:00
samples Char/Misc driver changes for 6.2-rc1 2022-12-16 03:49:24 -08:00
scripts kernel hardening fixes for v6.2-rc4 2023-01-14 10:04:00 -06:00
security mm: new primitive kvmemdup() 2023-01-18 17:12:47 -08:00
sound sound fixes for 6.2-rc4 2023-01-13 08:20:29 -06:00
tools selftests/vm: ksm_functional_tests: fix a typo in comment 2023-01-18 17:12:49 -08:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Ensure lockdep knows about kvm->lock vs. vcpu->mutex ordering rule 2023-01-11 13:32:21 -05:00
.clang-format iommufd for 6.2 2022-12-14 09:15:43 -08:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore *.rpm 2022-12-30 17:22:14 +09:00
.mailmap Sync with v6.2-rc4 2023-01-18 16:52:20 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: zram: zsmalloc: Add an additional co-maintainer 2022-12-15 16:37:49 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Sync with v6.2-rc4 2023-01-18 16:52:20 -08:00
Makefile Linux 6.2-rc4 2023-01-15 09:22:43 -06:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.