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Heiko Carstens 0861b5a754 s390/smp: fix ipl from cpu with non-zero address 
Commit af51160ebd ("s390/smp: initialize cpu_present_mask in
setup_arch") initializes the cpu_present_mask much earlier than
before. However the cpu detection code relies on the fact that iff
logical cpu 0 is marked present then also the corresponding physical
cpu address within the pcpu_devices array slot is valid.

Since commit 44fd22992c ("[PATCH] Register the boot-cpu in the cpu
maps earlier") this assumption is not true anymore. The patch marks
logical cpu 0 as present in common code without that architecture code
had a chance to setup the logical to physical map.

With that change the cpu detection code assumes that the physical cpu
address of cpu 0 is also 0, which is not necessarily true.
Subsequently the physical cpu address of the ipl cpu will be mapped to
a different logical cpu. If that cpu is brought online later the ipl
cpu will send itself an initial cpu reset sigp signal. This in turn
completely resets the ipl cpu and the system stops working.

A dump of such a system looks like a "store status" has been
forgotten. But actually the kernel itself removed all traces which
would allow to easily tell what went wrong.

To fix this initialize the logical to physical cpu address already in
smp_setup_processor_id(). In addition remove the initialization of the
cpu_present_mask and cpu_online_mask for cpu 0, since that has already
been done. Also add a sanity check, just in case common code will be
changed again...

The problem can be easily reproduced within a z/VM guest:

> chcpu -d 0
> vmcp ipl

Fixes: af51160ebd ("s390/smp: initialize cpu_present_mask in setup_arch")
Reported-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-03-22 08:21:20 +01:00
arch s390/smp: fix ipl from cpu with non-zero address 2017-03-22 08:21:20 +01:00
block blk-mq-sched: don't run the queue async from blk_mq_try_issue_directly() 2017-03-14 11:51:59 -06:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto net: Work around lockdep limitation in sockets that use sockets 2017-03-09 18:23:27 -08:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-03-14 21:31:23 -07:00
drivers SCSI fixes on 20170321 2017-03-21 13:10:17 -07:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs f2fs: combine nat_bits and free_nid_bitmap cache 2017-03-20 10:00:18 -04:00
include GPIO fixes for the v4.11 series: 2017-03-21 13:01:53 -07:00
init Change get_random_{int,log} to use the CRNG used by /dev/urandom and 2017-03-11 09:08:47 -08:00
ipc Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
kernel Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-18 08:33:44 -07:00
lib mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
mm mm, swap: Remove WARN_ON_ONCE() in free_swap_slot() 2017-03-21 14:13:19 -07:00
net NFS client fixes for 4.11 2017-03-17 14:16:22 -07:00
samples Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-03 11:38:56 -08:00
scripts Merge branch 'akpm' (patches from Andrew) 2017-03-10 08:34:42 -08:00
security Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
sound scripts/spelling.txt: add "disble(d)" pattern and fix typo instances 2017-03-09 17:01:09 -08:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-17 13:59:52 -07:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt KVM: arm/arm64: VGIC: Fix command handling while ITS being disabled 2017-03-07 15:44:08 +00:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:48:52 -04:00
.mailmap mailmap: add codeaurora.org names for nameless email commits 2017-01-10 18:31:55 -08:00
COPYING
CREDITS MAINTAINERS: Remove old e-mail address 2017-02-13 12:24:56 -05:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig
MAINTAINERS MAINTAINERS: usb251xb: remove reference inexistent file 2017-03-09 10:34:16 +01:00
Makefile Linux 4.11-rc3 2017-03-19 19:09:39 -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.