Revision aeb309b81c6bada783c3695528a3e10748e97285 authored by Huang Ying on 12 July 2019, 03:55:44 UTC, committed by Linus Torvalds on 12 July 2019, 18:05:43 UTC
Via commit 4b3ef9daa4fc ("mm/swap: split swap cache into 64MB trunks"), after swapoff, the address_space associated with the swap device will be freed. So swap_address_space() users which touch the address_space need some kind of mechanism to prevent the address_space from being freed during accessing. When mincore processes an unmapped range for swapped shmem pages, it doesn't hold the lock to prevent swap device from being swapped off. So the following race is possible: CPU1 CPU2 do_mincore() swapoff() walk_page_range() mincore_unmapped_range() __mincore_unmapped_range mincore_page as = swap_address_space() ... exit_swap_address_space() ... kvfree(spaces) find_get_page(as) The address space may be accessed after being freed. To fix the race, get_swap_device()/put_swap_device() is used to enclose find_get_page() to check whether the swap entry is valid and prevent the swap device from being swapoff during accessing. Link: http://lkml.kernel.org/r/20190611020510.28251-1-ying.huang@intel.com Fixes: 4b3ef9daa4fc ("mm/swap: split swap cache into 64MB trunks") Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Andrea Parri <andrea.parri@amarulasolutions.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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index.rst
.. The Linux Kernel documentation master file, created by
sphinx-quickstart on Fri Feb 12 13:51:46 2016.
You can adapt this file completely to your liking, but it should at least
contain the root `toctree` directive.
.. _linux_doc:
The Linux Kernel documentation
==============================
This is the top level of the kernel's documentation tree. Kernel
documentation, like the kernel itself, is very much a work in progress;
that is especially true as we work to integrate our many scattered
documents into a coherent whole. Please note that improvements to the
documentation are welcome; join the linux-doc list at vger.kernel.org if
you want to help out.
Licensing documentation
-----------------------
The following describes the license of the Linux kernel source code
(GPLv2), how to properly mark the license of individual files in the source
tree, as well as links to the full license text.
* :ref:`kernel_licensing`
User-oriented documentation
---------------------------
The following manuals are written for *users* of the kernel — those who are
trying to get it to work optimally on a given system.
.. toctree::
:maxdepth: 2
admin-guide/index
Firmware-related documentation
------------------------------
The following holds information on the kernel's expectations regarding the
platform firmwares.
.. toctree::
:maxdepth: 2
firmware-guide/index
Application-developer documentation
-----------------------------------
The user-space API manual gathers together documents describing aspects of
the kernel interface as seen by application developers.
.. toctree::
:maxdepth: 2
userspace-api/index
Introduction to kernel development
----------------------------------
These manuals contain overall information about how to develop the kernel.
The kernel community is quite large, with thousands of developers
contributing over the course of a year. As with any large community,
knowing how things are done will make the process of getting your changes
merged much easier.
.. toctree::
:maxdepth: 2
process/index
dev-tools/index
doc-guide/index
kernel-hacking/index
trace/index
maintainer/index
Kernel API documentation
------------------------
These books get into the details of how specific kernel subsystems work
from the point of view of a kernel developer. Much of the information here
is taken directly from the kernel source, with supplemental material added
as needed (or at least as we managed to add it — probably *not* all that is
needed).
.. toctree::
:maxdepth: 2
driver-api/index
core-api/index
media/index
networking/index
input/index
hwmon/index
gpu/index
security/index
sound/index
crypto/index
filesystems/index
vm/index
bpf/index
misc-devices/index
Architecture-specific documentation
-----------------------------------
These books provide programming details about architecture-specific
implementation.
.. toctree::
:maxdepth: 2
sh/index
x86/index
Filesystem Documentation
------------------------
The documentation in this section are provided by specific filesystem
subprojects.
.. toctree::
:maxdepth: 2
filesystems/ext4/index
Translations
------------
.. toctree::
:maxdepth: 2
translations/index
Indices and tables
==================
* :ref:`genindex`
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