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Michal Hocko 561b5e0709 mm/mmap.c: do not blow on PROT_NONE MAP_FIXED holes in the stack
Commit 1be7107fbe ("mm: larger stack guard gap, between vmas") has
introduced a regression in some rust and Java environments which are
trying to implement their own stack guard page.  They are punching a new
MAP_FIXED mapping inside the existing stack Vma.

This will confuse expand_{downwards,upwards} into thinking that the
stack expansion would in fact get us too close to an existing non-stack
vma which is a correct behavior wrt safety.  It is a real regression on
the other hand.

Let's work around the problem by considering PROT_NONE mapping as a part
of the stack.  This is a gros hack but overflowing to such a mapping
would trap anyway an we only can hope that usespace knows what it is
doing and handle it propely.

Fixes: 1be7107fbe ("mm: larger stack guard gap, between vmas")
Link: http://lkml.kernel.org/r/20170705182849.GA18027@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Debugged-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:33 -07:00
arch Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-09 11:21:31 -07:00
block Merge branch 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-07-06 20:57:13 -07:00
certs scripts/spelling.txt: add "intialise(d)" pattern and fix typo instances 2017-05-08 17:15:13 -07:00
crypto dmaengine updates for 4.13-rc1 2017-07-08 12:36:50 -07:00
Documentation mm: document highmem_is_dirtyable sysctl 2017-07-10 16:32:32 -07:00
drivers mm: drop useless local parameters of __register_one_node() 2017-07-10 16:32:32 -07:00
firmware firmware/Makefile: force recompilation if makefile changes 2017-05-08 17:15:10 -07:00
fs fs/proc/task_mmu.c: remove obsolete comment in show_map_vma() 2017-07-10 16:32:32 -07:00
include include/linux/backing-dev.h: simplify wb_stat_sum 2017-07-10 16:32:32 -07:00
init mm: allow slab_nomerge to be set at build time 2017-07-06 16:24:31 -07:00
ipc mqueue: fix a use-after-free in sys_mq_notify() 2017-07-09 14:37:19 -07:00
kernel mm: make PR_SET_THP_DISABLE immediately active 2017-07-10 16:32:31 -07:00
lib dmaengine updates for 4.13-rc1 2017-07-08 12:36:50 -07:00
mm mm/mmap.c: do not blow on PROT_NONE MAP_FIXED holes in the stack 2017-07-10 16:32:33 -07:00
net mpls: fix uninitialized in_label var warning in mpls_getroute 2017-07-08 11:26:41 +01:00
samples bpf: fix return in load_bpf_file 2017-07-05 09:05:28 +01:00
scripts Kbuild thin archives updates for v4.13 2017-07-07 15:11:12 -07:00
security Merge branch 'work.memdup_user' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-07-05 16:05:24 -07:00
sound main drm pull for v4.13 2017-07-09 18:48:37 -07:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-09 10:49:47 -07:00
usr ramfs: clarify help text that compression applies to ramfs as well as legacy ramdisk. 2017-07-06 16:24:30 -07:00
virt PPC: 2017-07-06 18:38:31 -07:00
.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 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 main drm pull for v4.13 2017-07-09 18:48:37 -07:00
Makefile Kbuild thin archives updates for v4.13 2017-07-07 15:11:12 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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.