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Linux kernel for uConsole
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Henry Burns ed11e60033 mm/zsmalloc.c: fix race condition in zs_destroy_pool 
commit 701d678599 upstream.

In zs_destroy_pool() we call flush_work(&pool->free_work).  However, we
have no guarantee that migration isn't happening in the background at
that time.

Since migration can't directly free pages, it relies on free_work being
scheduled to free the pages.  But there's nothing preventing an
in-progress migrate from queuing the work *after*
zs_unregister_migration() has called flush_work().  Which would mean
pages still pointing at the inode when we free it.

Since we know at destroy time all objects should be free, no new
migrations can come in (since zs_page_isolate() fails for fully-free
zspages).  This means it is sufficient to track a "# isolated zspages"
count by class, and have the destroy logic ensure all such pages have
drained before proceeding.  Keeping that state under the class spinlock
keeps the logic straightforward.

In this case a memory leak could lead to an eventual crash if compaction
hits the leaked page.  This crash would only occur if people are
changing their zswap backend at runtime (which eventually starts
destruction).

Link: http://lkml.kernel.org/r/20190809181751.219326-2-henryburns@google.com
Fixes: 48b4800a1c ("zsmalloc: page migration support")
Signed-off-by: Henry Burns <henryburns@google.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Henry Burns <henrywolfeburns@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Jonathan Adams <jwadams@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-29 08:28:57 +02:00
arch x86/boot: Fix boot regression caused by bootparam sanitizing 2019-08-29 08:28:54 +02:00
block block, bfq: handle NULL return value by bfq_init_rq() 2019-08-29 08:28:46 +02:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: chacha20poly1305 - fix atomic sleep when using async algorithm 2019-07-26 09:14:19 +02:00
Documentation x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16h 2019-08-29 08:28:53 +02:00
drivers dm zoned: properly handle backing device failure 2019-08-29 08:28:56 +02:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs userfaultfd_release: always remove uffd flags and clear vm_userfaultfd_ctx 2019-08-29 08:28:52 +02:00
include drm/i915/cfl: Add a new CFL PCI ID. 2019-08-25 10:48:01 +02:00
init initramfs: free initrd memory if opening /initrd.image fails 2019-06-15 11:54:01 +02:00
ipc ipc/mqueue.c: only perform resource calculation if user valid 2019-08-06 19:06:52 +02:00
kernel genirq: Properly pair kobject_del() with kobject_add() 2019-08-29 08:28:57 +02:00
lib test_firmware: fix a memory leak bug 2019-08-16 10:12:49 +02:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm/zsmalloc.c: fix race condition in zs_destroy_pool 2019-08-29 08:28:57 +02:00
net libceph: fix PG split vs OSD (re)connect race 2019-08-29 08:28:50 +02:00
samples samples, bpf: suppress compiler warning 2019-07-14 08:11:04 +02:00
scripts kbuild: Check for unknown options with cc-option usage in Kconfig and clang 2019-08-25 10:47:56 +02:00
security selinux: fix memory leak in policydb_init() 2019-08-06 19:06:54 +02:00
sound ASoC: ti: davinci-mcasp: Correct slot_width posed constraint 2019-08-29 08:28:32 +02:00
tools selftests: kvm: Adding config fragments 2019-08-29 08:28:48 +02:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt KVM: arm/arm64: Sync ICH_VMCR_EL2 back when about to block 2019-08-25 10:47:59 +02:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS platform/x86: Add Intel AtomISP2 dummy / power-management driver 2019-04-20 09:16:02 +02:00
Makefile Linux 4.19.68 2019-08-25 10:48:06 +02:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

README 

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.
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.