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Borislav Petkov 1f74c8a647 x86/mce: Do not overwrite MCi_STATUS in mce_no_way_out()
mce_no_way_out() does a quick check during #MC to see whether some of
the MCEs logged would require the kernel to panic immediately. And it
passes a struct mce where MCi_STATUS gets written.

However, after having saved a valid status value, the next iteration
of the loop which goes over the MCA banks on the CPU, overwrites the
valid status value because we're using struct mce as storage instead of
a temporary variable.

Which leads to MCE records with an empty status value:

  mce: [Hardware Error]: CPU 0: Machine Check Exception: 6 Bank 0: 0000000000000000
  mce: [Hardware Error]: RIP 10:<ffffffffbd42fbd7> {trigger_mce+0x7/0x10}

In order to prevent the loss of the status register value, return
immediately when severity is a panic one so that we can panic
immediately with the first fatal MCE logged. This is also the intention
of this function and not to noodle over the banks while a fatal MCE is
already logged.

Tony: read the rest of the MCA bank to populate the struct mce fully.

Suggested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20180622095428.626-8-bp@alien8.de
2018-06-22 14:35:50 +02:00
arch x86/mce: Do not overwrite MCi_STATUS in mce_no_way_out() 2018-06-22 14:35:50 +02:00
block Merge branch 'hch.procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-06-04 10:00:01 -07:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto Merge branch 'work.aio-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-06-04 13:57:43 -07:00
Documentation Merge branch 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 21:34:39 -07:00
drivers Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 20:27:54 -07:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-06-04 15:23:48 -07:00
include Merge branch 'timers-2038-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 21:02:18 -07:00
init init/main.c: include <linux/mem_encrypt.h> 2018-05-25 18:12:11 -07:00
ipc Merge branch 'timers-2038-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 21:02:18 -07:00
kernel Merge branch 'timers-2038-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 21:02:18 -07:00
lib Merge branch 'x86-dax-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 19:23:13 -07:00
LICENSES LICENSES: Add Linux-OpenIB license text 2018-04-27 16:41:53 -06:00
mm Merge branch 'work.aio-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-06-04 13:57:43 -07:00
net Merge branch 'work.aio-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-06-04 13:57:43 -07:00
samples x86/cpufeature: Guard asm_volatile_goto usage for BPF compilation 2018-05-13 21:49:14 +02:00
scripts There's been a fair amount of work in the docs tree this time around, 2018-06-04 12:34:27 -07:00
security Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-06-04 15:21:19 -07:00
sound ALSA: hda - Fix runtime PM 2018-05-24 20:16:47 +02:00
tools Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 17:14:22 -07:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-06-04 15:23:48 -07:00
.clang-format clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap Merge candidates for 4.17 merge window 2018-04-06 17:35:43 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 16:40:11 -07:00
Makefile Linux 4.17 2018-06-03 14:15:21 -07:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.