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Qiuxu Zhuo 2da241c5ed x86/lib: Revert to _ASM_EXTABLE_UA() for {get,put}_user() fixups 
commit 8eed4e00a3 upstream.

During memory error injection test on kernels >= v6.4, the kernel panics
like below. However, this issue couldn't be reproduced on kernels <= v6.3.

  mce: [Hardware Error]: CPU 296: Machine Check Exception: f Bank 1: bd80000000100134
  mce: [Hardware Error]: RIP 10:<ffffffff821b9776> {__get_user_nocheck_4+0x6/0x20}
  mce: [Hardware Error]: TSC 411a93533ed ADDR 346a8730040 MISC 86
  mce: [Hardware Error]: PROCESSOR 0:a06d0 TIME 1706000767 SOCKET 1 APIC 211 microcode 80001490
  mce: [Hardware Error]: Run the above through 'mcelog --ascii'
  mce: [Hardware Error]: Machine check: Data load in unrecoverable area of kernel
  Kernel panic - not syncing: Fatal local machine check

The MCA code can recover from an in-kernel #MC if the fixup type is
EX_TYPE_UACCESS, explicitly indicating that the kernel is attempting to
access userspace memory. However, if the fixup type is EX_TYPE_DEFAULT
the only thing that is raised for an in-kernel #MC is a panic.

ex_handler_uaccess() would warn if users gave a non-canonical addresses
(with bit 63 clear) to {get, put}_user(), which was unexpected.

Therefore, commit

  b19b74bc99 ("x86/mm: Rework address range check in get_user() and put_user()")

replaced _ASM_EXTABLE_UA() with _ASM_EXTABLE() for {get, put}_user()
fixups. However, the new fixup type EX_TYPE_DEFAULT results in a panic.

Commit

  6014bc2756 ("x86-64: make access_ok() independent of LAM")

added the check gp_fault_address_ok() right before the WARN_ONCE() in
ex_handler_uaccess() to not warn about non-canonical user addresses due
to LAM.

With that in place, revert back to _ASM_EXTABLE_UA() for {get,put}_user()
exception fixups in order to be able to handle in-kernel MCEs correctly
again.

  [ bp: Massage commit message. ]

Fixes: b19b74bc99 ("x86/mm: Rework address range check in get_user() and put_user()")
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20240129063842.61584-1-qiuxu.zhuo@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2024-02-16 19:14:28 +01:00
arch x86/lib: Revert to _ASM_EXTABLE_UA() for {get,put}_user() fixups 2024-02-16 19:14:28 +01:00
block blk-iocost: Fix an UBSAN shift-out-of-bounds warning 2024-02-16 19:14:27 +01:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto crypto: api - Disallow identical driver names 2024-01-31 16:20:54 -08:00
Documentation net: sysfs: Fix /sys/class/net/<iface> path 2024-02-05 20:17:10 +00:00
drivers Revert "drm/amd/pm: fix the high voltage and temperature issue" 2024-02-16 19:14:28 +01:00
fs ceph: always set initial i_blkbits to CEPH_FSCRYPT_BLOCK_SHIFT 2024-02-16 19:14:26 +01:00
include libceph: just wait for more data to be available on the socket 2024-02-16 19:14:26 +01:00
init rootfs: Fix support for rootfstype= when root= is given 2024-01-25 15:45:15 -08:00
io_uring io_uring: adjust defer tw counting 2024-01-25 15:45:30 -08:00
ipc Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
kernel perf: Fix the nr_addr_filters fix 2024-02-05 20:17:06 +00:00
lib kunit: run test suites only after module initialization completes 2024-02-05 20:17:07 +00:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: Introduce flush_cache_vmap_early() 2024-02-16 19:14:25 +01:00
net libceph: just wait for more data to be available on the socket 2024-02-16 19:14:26 +01:00
rust rust: Ignore preserve-most functions 2024-01-25 15:45:09 -08:00
samples Landlock updates for v6.7-rc1 2023-11-03 09:28:53 -10:00
scripts scripts/get_abi: fix source path leak 2024-01-31 16:21:00 -08:00
security lsm: new security_file_ioctl_compat() hook 2024-01-31 16:21:00 -08:00
sound ALSA: usb-audio: add quirk for RODE NT-USB+ 2024-02-16 19:14:27 +01:00
tools selftests: core: include linux/close_range.h for CLOSE_RANGE_* macros 2024-02-16 19:14:27 +01:00
usr arch: Remove Itanium (IA-64) architecture 2023-09-11 08:13:17 +00:00
virt KVM/arm64 fixes for 6.7, part #2 2023-12-22 18:03:54 -05:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.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: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: generate kernel.spec in rpmbuild/SPECS/ 2023-10-03 20:49:09 +09:00
.mailmap 12 hotfixes. 2 are cc:stable and the remainder either address post-6.7 2024-01-05 13:46:18 -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 12 hotfixes. 2 are cc:stable and the remainder either address post-6.7 2024-01-05 13:46:18 -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 12 hotfixes. 2 are cc:stable and the remainder either address post-6.7 2024-01-05 13:46:18 -08:00
Makefile Linux 6.7.4 2024-02-05 20:17:12 +00:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

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.