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Ard Biesheuvel 5c6360ee4a ARM: 8988/1: mmu: fix crash in EFI calls due to p4d typo in create_mapping_late()
Commit

  84e6ffb2c4 ("arm: add support for folded p4d page tables")

updated create_mapping_late() to take folded P4Ds into account when
creating mappings, but inverted the p4d_alloc() failure test, resulting
in no mapping to be created at all.

When the EFI rtc driver subsequently tries to invoke the EFI GetTime()
service, the memory regions covering the EFI data structures are missing
from the page tables, resulting in a crash like

  Unable to handle kernel paging request at virtual address 5ae0cf28
  pgd = (ptrval)
  [5ae0cf28] *pgd=80000040205003, *pmd=00000000
  Internal error: Oops: 207 [#1] SMP THUMB2
  Modules linked in:
  CPU: 0 PID: 7 Comm: kworker/u32:0 Not tainted 5.7.0+ #92
  Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
  Workqueue: efi_rts_wq efi_call_rts
  PC is at efi_call_rts+0x94/0x294
  LR is at efi_call_rts+0x83/0x294
  pc : [<c0b4f098>]    lr : [<c0b4f087>]    psr: 30000033
  sp : e6219ef0  ip : 00000000  fp : ffffe000
  r10: 00000000  r9 : 00000000  r8 : 30000013
  r7 : e6201dd0  r6 : e6201ddc  r5 : 00000000  r4 : c181f264
  r3 : 5ae0cf10  r2 : 00000001  r1 : e6201dd0  r0 : e6201ddc
  Flags: nzCV  IRQs on  FIQs on  Mode SVC_32  ISA Thumb  Segment none
  Control: 70c5383d  Table: 661cc840  DAC: 00000001
  Process kworker/u32:0 (pid: 7, stack limit = 0x(ptrval))
  ...
  [<c0b4f098>] (efi_call_rts) from [<c0448219>] (process_one_work+0x16d/0x3d8)
  [<c0448219>] (process_one_work) from [<c0448581>] (worker_thread+0xfd/0x408)
  [<c0448581>] (worker_thread) from [<c044ca7b>] (kthread+0x103/0x104)
  ...

Fixes: 84e6ffb2c4 ("arm: add support for folded p4d page tables")
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2020-07-21 16:32:56 +01:00
arch ARM: 8988/1: mmu: fix crash in EFI calls due to p4d typo in create_mapping_late() 2020-07-21 16:32:56 +01:00
block block-5.8-2020-07-05 2020-07-05 10:45:31 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto crypto: af_alg - fix use-after-free in af_alg_accept() due to bh_lock_sock() 2020-06-18 17:09:54 +10:00
Documentation Kbuild fixes for v5.8 (2nd) 2020-07-05 12:14:24 -07:00
drivers A set of interrupt chip driver fixes: 2020-07-05 12:22:35 -07:00
fs io_uring-5.8-2020-07-05 2020-07-05 10:41:33 -07:00
include pci-v5.8-fixes-1 2020-07-03 12:14:51 -07:00
init kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang 2020-07-02 00:57:45 +09:00
ipc mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
kernel A single fix for a printk format warning in RCU. 2020-07-05 12:21:28 -07:00
lib Peter Zijlstra says: 2020-06-28 09:42:47 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/page_alloc: fix documentation error 2020-07-03 16:15:25 -07:00
net Fixes for a umask bug on exported filesystems lacking ACL support, a 2020-07-02 20:35:33 -07:00
samples samples/vfs: avoid warning in statx override 2020-07-03 16:15:25 -07:00
scripts Kbuild fixes for v5.8 (2nd) 2020-07-05 12:14:24 -07:00
security Two simple fixes for v5.8: 2020-06-30 12:21:53 -07:00
sound sound fixes for 5.8-rc3 2020-06-25 09:15:24 -07:00
tools A series of fixes for x86: 2020-07-05 12:23:49 -07:00
usr bpfilter: match bit size of bpfilter_umh to that of the kernel 2020-05-17 18:52:01 +09:00
virt MIPS: 2020-06-12 11:05:52 -07:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: Do not track defconfig from make savedefconfig 2020-07-05 16:15:46 +09:00
.mailmap A fair amount of stuff this time around, dominated by yet another massive 2020-06-01 15:45:27 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS mailmap: change email for Ricardo Ribalda 2020-05-25 18:59:59 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Devicetree fixes for v5.8, take 2: 2020-07-02 22:46:05 -07:00
Makefile Linux 5.8-rc4 2020-07-05 16:20:22 -07:00
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.