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Vasily Averin fc37a3b8b4 ipc sem: use kvmalloc for sem_undo allocation
Patch series "ipc: allocations cleanup", v2.

Some ipc objects use the wrong allocation functions: small objects can use
kmalloc(), and vice versa, potentially large objects can use kmalloc().

This patch (of 2):

Size of sem_undo can exceed one page and with the maximum possible nsems =
32000 it can grow up to 64Kb.  Let's switch its allocation to kvmalloc to
avoid user-triggered disruptive actions like OOM killer in case of
high-order memory shortage.

User triggerable high order allocations are quite a problem on heavily
fragmented systems.  They can be a DoS vector.

Link: https://lkml.kernel.org/r/ebc3ac79-3190-520d-81ce-22ad194986ec@virtuozzo.com
Link: https://lkml.kernel.org/r/a6354fd9-2d55-2e63-dd4d-fa7dc1d11134@virtuozzo.com
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:07 -07:00
arch kprobes: remove duplicated strong free_insn_page in x86 and s390 2021-07-01 11:06:06 -07:00
block block-5.13-2021-05-22 2021-05-22 07:40:34 -10:00
certs Kbuild updates for v5.13 (2nd) 2021-05-08 10:00:11 -07:00
crypto async_xor: check src_offs is not NULL before updating it 2021-06-10 19:40:14 -07:00
Documentation kernel.h: split out kstrtox() and simple_strtox() to a separate header 2021-07-01 11:06:05 -07:00
drivers kernel.h: split out panic and oops helpers 2021-07-01 11:06:04 -07:00
fs exec: remove checks in __register_bimfmt() 2021-07-01 11:06:06 -07:00
include kcov: add __no_sanitize_coverage to fix noinstr for all architectures 2021-07-01 11:06:06 -07:00
init init: print out unknown kernel parameters 2021-07-01 11:06:06 -07:00
ipc ipc sem: use kvmalloc for sem_undo allocation 2021-07-01 11:06:07 -07:00
kernel x86: signal: don't do sas_ss_reset() until we are certain that sigframe won't be abandoned 2021-07-01 11:06:06 -07:00
lib lib/decompressors: remove set but not used variabled 'level' 2021-07-01 11:06:06 -07:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm mm: device exclusive memory access 2021-07-01 11:06:03 -07:00
net net/ipv5/tcp: use vma_lookup() in tcp_zerocopy_receive() 2021-06-29 10:53:51 -07:00
samples VFIO fixes for v5.13-rc5 2021-06-03 11:52:24 -07:00
scripts checkpatch: do not complain about positive return values starting with EPOLL 2021-07-01 11:06:06 -07:00
security trusted-keys: match tpm_get_ops on all return paths 2021-05-12 22:36:37 +03:00
sound ASoC: rt5645: Avoid upgrading static warnings to errors 2021-06-24 12:22:27 +02:00
tools selftests/vm/pkeys: exercise x86 XSAVE init state 2021-07-01 11:06:06 -07:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt virt/kvm: use vma_lookup() instead of find_vma_intersection() 2021-06-29 10:53:51 -07:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.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: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Marek's other e-mail address and identity without diacritics 2021-06-24 19:40:54 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: move Murali Karicheri to credits 2021-04-29 15:47:30 -07:00
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 MAINTAINERS: add myself as designated reviewer for generic string library 2021-07-01 11:06:05 -07:00
Makefile Linux 5.13 2021-06-27 15:21:11 -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.