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Vasily Averin 831246570d kernel/notifier.c: double register detection
By design notifiers can be registerd once only, 2nd register attempt
called by mistake silently corrupts notifiers list.

A few years ago I investigated described problem, the host was power
cycled because of notifier list corruption.  I've prepared this patch
and applied it to the OpenVZ kernel and sent this patch but nobody
commented on it.  Later it helped us to detect a similar problem in the
OpenVz kernel.

Mistakes with notifier registration can happen for example during
subsystem initialization from different namespaces, or because of a lost
unregister in the roll-back path on initialization failures.

The proposed check cannot prevent the described problem, however it
allows us to detect its reason quickly without coredump analysis.

Link: http://lkml.kernel.org/r/04127e71-4782-9bbb-fe5a-7c01e93a99b0@virtuozzo.com
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:49 -07:00
arch compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING 2019-05-14 19:52:48 -07:00
block for-5.2/block-20190507 2019-05-07 18:14:36 -07:00
certs kexec, KEYS: Make use of platform keyring for signature verify 2019-02-04 17:34:07 -05:00
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2019-05-07 22:03:58 -07:00
Documentation mm: shuffle initial free memory to improve memory-side-cache utilization 2019-05-14 19:52:48 -07:00
drivers mtd: rawnand: vf610_nfc: add initializer to avoid -Wmaybe-uninitialized 2019-05-14 19:52:48 -07:00
fs Merge branch 'akpm' (patches from Andrew) 2019-05-14 10:10:55 -07:00
include compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING 2019-05-14 19:52:48 -07:00
init mm: shuffle initial free memory to improve memory-side-cache utilization 2019-05-14 19:52:48 -07:00
ipc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2019-05-07 22:03:58 -07:00
kernel kernel/notifier.c: double register detection 2019-05-14 19:52:49 -07:00
lib compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING 2019-05-14 19:52:48 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/mincore.c: make mincore() more conservative 2019-05-14 19:52:48 -07:00
net Merge branch 'akpm' (patches from Andrew) 2019-05-14 10:10:55 -07:00
samples samples: add .gitignore for pidfd-metadata 2019-05-10 11:50:52 +02:00
scripts gcc-plugin fix: 2019-05-13 16:01:52 -07:00
security Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-05-13 15:15:00 -07:00
sound sound updates for 5.2-rc1 2019-05-09 08:26:55 -07:00
tools pci-v5.2-changes 2019-05-14 10:30:10 -07:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt mm/mmu_notifier: convert user range->blockable to helper function 2019-05-14 09:47:49 -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 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 .gitignore: add more all*.config patterns 2019-05-08 09:47:46 +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 Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
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 - Core Frameworks 2019-05-14 10:39:08 -07:00
Makefile Kbuild updates for v5.2 2019-05-08 12:25:12 -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.