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Heiko Carstens 4f18d869ff s390: fix stfle zero padding
The stfle inline assembly returns the number of double words written
(condition code 0) or the double words it would have written
(condition code 3), if the memory array it got as parameter would have
been large enough.

The current stfle implementation assumes that the array is always
large enough and clears those parts of the array that have not been
written to with a subsequent memset call.

If however the array is not large enough memset will get a negative
length parameter, which means that memset clears memory until it gets
an exception and the kernel crashes.

To fix this simply limit the maximum length. Move also the inline
assembly to an extra function to avoid clobbering of register 0, which
might happen because of the added min_t invocation together with code
instrumentation.

The bug was introduced with commit 14375bc4eb ("[S390] cleanup
facility list handling") but was rather harmless, since it would only
write to a rather large array. It became a potential problem with
commit 3ab121ab18 ("[S390] kernel: Add z/VM LGR detection"). Since
then it writes to an array with only four double words, while some
machines already deliver three double words. As soon as machines have
a facility bit within the fifth double a crash on IPL would happen.

Fixes: 14375bc4eb ("[S390] cleanup facility list handling")
Cc: <stable@vger.kernel.org> # v2.6.37+
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-06-19 17:54:27 +02:00
arch s390: fix stfle zero padding 2019-06-19 17:54:27 +02:00
block block: print offending values when cloned rq limits are exceeded 2019-05-31 15:12:34 -06:00
certs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
crypto treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
Documentation s390/sclp: remove call home support 2019-06-19 17:54:27 +02:00
drivers s390/sclp: remove call home support 2019-06-19 17:54:27 +02:00
fs for-linus-20190601 2019-06-02 09:27:44 -07:00
include processor: get rid of cpu_relax_yield 2019-06-15 12:25:55 +02:00
init treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 167 2019-05-30 11:26:39 -07:00
ipc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 52 2019-05-24 17:36:42 +02:00
kernel processor: get rid of cpu_relax_yield 2019-06-15 12:25:55 +02:00
lib RAID/s390: remove invalid 'r' inline asm operand modifier 2019-06-11 09:48:25 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm, compaction: make sure we isolate a valid PFN 2019-06-01 15:51:32 -07:00
net SPDX update for 5.2-rc3, round 1 2019-05-31 08:34:32 -07:00
samples treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 206 2019-05-30 11:29:53 -07:00
scripts Merge branch 'akpm' (patches from Andrew) 2019-06-02 08:51:30 -07:00
security Merge branch 'next-fixes-for-5.2-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2019-05-31 11:08:44 -07:00
sound treewide: fix typos of SPDX-License-Identifier 2019-06-01 18:29:58 +02:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-06-02 11:08:12 -07:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt Fixes for PPC and s390. 2019-06-02 10:19:39 -07:00
.clang-format Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-17 11:26:25 -07:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes
.gitignore .gitignore: exclude .get_maintainer.ignore and .gitattributes 2019-05-18 11:49:54 +09:00
.mailmap A reasonably busy cycle for docs, including: 2019-05-08 12:42:50 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Farewell Martin Schwidefsky 2019-05-31 10:14:11 +02:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS docs: s390: convert docs to ReST and rename to *.rst 2019-06-11 09:48:14 +02:00
Makefile Linux 5.2-rc3 2019-06-02 13:55:33 -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.