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Peter Xu 49d6d7fb63 mm/uffd: fix pte marker when fork() without fork event
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: c56d1b62cc ("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>
2023-01-18 17:02:19 -08:00
arch - Make sure the poking PGD is pinned for Xen PV as it requires it this way 2023-01-15 07:17:44 -06:00
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 Sync with v6.2-rc4 2023-01-18 16:52:20 -08:00
drivers - Fix the EDAC device's confusion in the polling setting units 2023-01-15 07:12:58 -06:00
fs Sync with v6.2-rc4 2023-01-18 16:52:20 -08:00
include Sync with v6.2-rc4 2023-01-18 16:52:20 -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 modules-6.2-rc4 2023-01-14 08:17:27 -06:00
lib Sync with v6.2-rc4 2023-01-18 16:52:20 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/uffd: fix pte marker when fork() without fork event 2023-01-18 17:02:19 -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 kernel hardening fixes for v6.2-rc1 2022-12-23 12:00:24 -08:00
sound sound fixes for 6.2-rc4 2023-01-13 08:20:29 -06:00
tools Sync with v6.2-rc4 2023-01-18 16:52:20 -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 scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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.