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Russell King 67556d7a85 ARM: kexec: avoid allocating crashkernel region outside lowmem
Allocating the crashkernel region outside lowmem causes the kernel to
oops while trying to kexec into the new kernel:

Loading crashdump kernel...
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = edd70000
[00000000] *pgd=de19e835
Internal error: Oops: 817 [#2] SMP ARM
Modules linked in: ...
CPU: 0 PID: 689 Comm: sh Not tainted 4.12.0-rc3-next-20170601-04015-gc3a5a20
Hardware name: Generic DRA74X (Flattened Device Tree)
task: edb32f00 task.stack: edf18000
PC is at memcpy+0x50/0x330
LR is at 0xe3c34001
pc : [<c04baf30>]    lr : [<e3c34001>]    psr: 800c0193
sp : edf19c2c  ip : 0a000001  fp : c0553170
r10: c055316e  r9 : 00000001  r8 : e3130001
r7 : e4903004  r6 : 0a000014  r5 : e3500000  r4 : e59f106c
r3 : e59f0074  r2 : ffffffe8  r1 : c010fb88  r0 : 00000000
Flags: Nzcv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 10c5387d  Table: add7006a  DAC: 00000051
Process sh (pid: 689, stack limit = 0xedf18218)
Stack: (0xedf19c2c to 0xedf1a000)
...
[<c04baf30>] (memcpy) from [<c010fae0>] (machine_kexec+0xa8/0x12c)
[<c010fae0>] (machine_kexec) from [<c01e4104>] (__crash_kexec+0x5c/0x98)
[<c01e4104>] (__crash_kexec) from [<c01e419c>] (crash_kexec+0x5c/0x68)
[<c01e419c>] (crash_kexec) from [<c010c5c0>] (die+0x228/0x490)
[<c010c5c0>] (die) from [<c011e520>] (__do_kernel_fault.part.0+0x54/0x1e4)
[<c011e520>] (__do_kernel_fault.part.0) from [<c082412c>] (do_page_fault+0x1e8/0x400)
[<c082412c>] (do_page_fault) from [<c010135c>] (do_DataAbort+0x38/0xb8)
[<c010135c>] (do_DataAbort) from [<c0823584>] (__dabt_svc+0x64/0xa0)

This is caused by image->control_code_page being a highmem page, so
page_address(image->control_code_page) returns NULL.  In any case, we
don't want the control page to be a highmem page.

We already limit the crash kernel region to the top of 32-bit physical
memory space.  Also limit it to the top of lowmem in physical space.

Reported-by: Keerthy <j-keerthy@ti.com>
Tested-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2017-07-20 11:37:15 +01:00
Documentation A single GPIO patch fixing the compatible string for the 2017-06-23 17:40:41 -07:00
arch ARM: kexec: avoid allocating crashkernel region outside lowmem 2017-07-20 11:37:15 +01:00
block block: provide bio_uninit() free freeing integrity/task associations 2017-06-28 15:30:13 -06:00
certs scripts/spelling.txt: add "intialise(d)" pattern and fix typo instances 2017-05-08 17:15:13 -07:00
crypto crypto : asymmetric_keys : verify_pefile:zero memory content before freeing 2017-06-09 13:29:50 +10:00
drivers A last fix for v4.12, an IRQ problem reported early in the merge window 2017-07-01 08:39:13 -07:00
firmware firmware/Makefile: force recompilation if makefile changes 2017-05-08 17:15:10 -07:00
fs Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2017-06-30 10:22:59 -07:00
include moduleparam: fix doc: hwparam_irq configures an IRQ 2017-07-02 15:37:23 -07:00
init Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-10 10:30:46 -07:00
ipc mm: introduce kv[mz]alloc helpers 2017-05-08 17:15:12 -07:00
kernel Two fixes: 2017-06-30 17:18:57 -07:00
lib lib/cmdline.c: fix get_options() overflow while parsing ranges 2017-06-23 16:15:55 -07:00
mm slub: make sysfs file removal asynchronous 2017-06-23 16:15:55 -07:00
net net: handle NAPI_GRO_FREE_STOLEN_HEAD case also in napi_frags_finish() 2017-06-29 15:54:13 -04:00
samples samples/bpf: run cleanup routines when receiving SIGTERM 2017-05-11 21:43:30 -04:00
scripts Kbuild fixes for v4.12 (2nd) 2017-06-24 16:18:00 -07:00
security selinux: fix double free in selinux_parse_opts_str() 2017-06-13 17:34:22 +10:00
sound ALSA: hda - Fix endless loop of codec configure 2017-06-28 12:10:05 +02:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-01 08:46:52 -07:00
usr initramfs: fix disabling of initramfs (and its compression) 2017-06-02 15:07:37 -07:00
virt KVM: arm/arm64: Handle possible NULL stage2 pud when ageing pages 2017-06-06 15:28:40 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS avr32: remove support for AVR32 architecture 2017-05-01 09:27:15 +02:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS Update maintainer email 2017-06-26 12:25:59 -07:00
Makefile Linux 4.12 2017-07-02 16:07:02 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

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.