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Andrea Arcangeli a425d3584e userfaultfd: shmem: avoid a lockup resulting from corrupted page->flags
Use the non atomic version of __SetPageUptodate while the page is still
private and not visible to lookup operations.  Using the non atomic
version after the page is already visible to lookups is unsafe as there
would be concurrent lock_page operation modifying the page->flags while
it runs.

This solves a lockup in find_lock_entry with the userfaultfd_shmem
selftest.

  userfaultfd_shm D14296   691      1 0x00000004
  Call Trace:
   schedule+0x3d/0x90
   schedule_timeout+0x228/0x420
   io_schedule_timeout+0xa4/0x110
   __lock_page+0x12d/0x170
   find_lock_entry+0xa4/0x190
   shmem_getpage_gfp+0xb9/0xc30
   shmem_fault+0x70/0x1c0
   __do_fault+0x21/0x150
   handle_mm_fault+0xec9/0x1490
   __do_page_fault+0x20d/0x520
   trace_do_page_fault+0x61/0x270
   do_async_page_fault+0x19/0x80
   async_page_fault+0x25/0x30

Link: http://lkml.kernel.org/r/20170116180408.12184-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-22 16:41:29 -08:00
arch parisc: use generic current.h 2017-02-22 16:41:27 -08:00
block block: use for_each_thread() in sys_ioprio_set()/sys_ioprio_get() 2017-02-22 16:41:27 -08:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto crypto: algif_aead - Fix kernel panic on list_del 2017-02-03 17:45:48 +08:00
Documentation slub: make sysfs directories for memcg sub-caches optional 2017-02-22 16:41:27 -08:00
drivers mm, dax: change pmd_fault() to take only vmf parameter 2017-02-22 16:41:26 -08:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs userfaultfd: shmem: allow registration of shared memory ranges 2017-02-22 16:41:28 -08:00
include userfaultfd: shmem: allow registration of shared memory ranges 2017-02-22 16:41:28 -08:00
init slub: make sysfs directories for memcg sub-caches optional 2017-02-22 16:41:27 -08:00
ipc ipc/sem.c: fix incorrect sem_lock pairing 2017-01-10 18:31:55 -08:00
kernel userfaultfd: non-cooperative: Add fork() event 2017-02-22 16:41:28 -08:00
lib dma-debug: add comment for failed to check map error 2017-02-22 16:41:26 -08:00
mm userfaultfd: shmem: avoid a lockup resulting from corrupted page->flags 2017-02-22 16:41:29 -08:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-02-22 10:15:09 -08:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-02-22 10:15:09 -08:00
scripts scripts/tags.sh: include arch/Kconfig* for tags generation 2017-02-22 16:41:26 -08:00
security driver core patches for 4.11-rc1 2017-02-22 11:44:32 -08:00
sound ALSA: hda - adding a new NV HDMI/DP codec ID in the driver 2017-02-09 08:57:47 +01:00
tools userfaultfd: shmem: add userfaultfd_shmem test 2017-02-22 16:41:29 -08:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt KVM/ARM updates for 4.10-rc4 2017-01-17 15:04:59 +01:00
.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 Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:48:52 -04:00
.mailmap mailmap: add codeaurora.org names for nameless email commits 2017-01-10 18:31:55 -08:00
COPYING
CREDITS MAINTAINERS: Remove old e-mail address 2017-02-13 12:24:56 -05:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig
MAINTAINERS dax: update MAINTAINERS entries for FS DAX 2017-02-22 16:41:26 -08:00
Makefile Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-02-20 12:21:13 -08:00
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.