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Dave Young af16489848 x86/efi: Update e820 with reserved EFI boot services data to fix kexec breakage
Michael Weiser reported that he got this error during a kexec rebooting:

  esrt: Unsupported ESRT version 2904149718861218184.

The ESRT memory stays in EFI boot services data, and it was reserved
in kernel via efi_mem_reserve().  The initial purpose of the reservation
is to reuse the EFI boot services data across kexec reboot. For example
the BGRT image data and some ESRT memory like Michael reported.

But although the memory is reserved it is not updated in the X86 E820 table,
and kexec_file_load() iterates system RAM in the IO resource list to find places
for kernel, initramfs and other stuff. In Michael's case the kexec loaded
initramfs overwrote the ESRT memory and then the failure happened.

Since kexec_file_load() depends on the E820 table being updated, just fix this
by updating the reserved EFI boot services memory as reserved type in E820.

Originally any memory descriptors with EFI_MEMORY_RUNTIME attribute are
bypassed in the reservation code path because they are assumed as reserved.

But the reservation is still needed for multiple kexec reboots,
and it is the only possible case we come here thus just drop the code
chunk, then everything works without side effects.

On my machine the ESRT memory sits in an EFI runtime data range, it does
not trigger the problem, but I successfully tested with BGRT instead.
both kexec_load() and kexec_file_load() work and kdump works as well.

[ mingo: Edited the changelog. ]

Reported-by: Michael Weiser <michael@weiser.dinsnail.net>
Tested-by: Michael Weiser <michael@weiser.dinsnail.net>
Signed-off-by: Dave Young <dyoung@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kexec@lists.infradead.org
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191204075233.GA10520@dhcp-128-65.nay.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-04 11:15:30 +01:00
Documentation chrome platform changes for v5.5 2019-12-03 14:37:12 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch x86/efi: Update e820 with reserved EFI boot services data to fix kexec breakage 2019-12-04 11:15:30 +01:00
block compat_ioctl: remove most of fs/compat_ioctl.c 2019-12-01 13:46:15 -08:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2019-11-25 19:49:58 -08:00
drivers chrome platform changes for v5.5 2019-12-03 14:37:12 -08:00
fs New code for 5.5: 2019-12-03 13:18:34 -08:00
include chrome platform changes for v5.5 2019-12-03 14:37:12 -08:00
init Kbuild updates for v5.5 2019-12-02 17:35:04 -08:00
ipc y2038: remove CONFIG_64BIT_TIME 2019-11-15 14:38:27 +01:00
kernel Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-12-03 12:20:25 -08:00
lib pci-v5.5-changes 2019-12-03 13:58:22 -08:00
mm mm/page_io.c: annotate refault stalls from swap_readpage 2019-12-01 12:59:11 -08:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-12-01 20:35:03 -08:00
samples New tracing features: 2019-11-27 11:42:01 -08:00
scripts Kbuild updates for v5.5 2019-12-02 17:35:04 -08:00
security + Features 2019-12-03 12:51:35 -08:00
sound compat_ioctl: remove most of fs/compat_ioctl.c 2019-12-01 13:46:15 -08:00
tools pci-v5.5-changes 2019-12-03 13:58:22 -08:00
usr kbuild: move headers_check rule to usr/include/Makefile 2019-11-15 00:23:10 +09:00
virt KVM: Fix jump label out_free_* in kvm_init() 2019-11-23 11:29:17 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore modpost: dump missing namespaces into a single modules.nsdeps file 2019-11-11 20:10:01 +09:00
.mailmap Here's the main documentation changes for 5.5: 2019-12-02 11:51:02 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Linux 5.4-rc4 2019-10-29 04:43:29 -06:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS pci-v5.5-changes 2019-12-03 13:58:22 -08:00
Makefile Kbuild updates for v5.5 2019-12-02 17:35:04 -08:00
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.