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Kirill A. Shutemov 591a3d7c09 mm: Fix false-positive VM_BUG_ON() in page_cache_{get,add}_speculative()
0day testing by Fengguang Wu triggered this crash while running Trinity:

  kernel BUG at include/linux/pagemap.h:151!
  ...
  CPU: 0 PID: 458 Comm: trinity-c0 Not tainted 4.11.0-rc2-00251-g2947ba0 #1
  ...
  Call Trace:
   __get_user_pages_fast()
   get_user_pages_fast()
   get_futex_key()
   futex_requeue()
   do_futex()
   SyS_futex()
   do_syscall_64()
   entry_SYSCALL64_slow_path()

It' VM_BUG_ON() due to false-negative in_atomic(). We call
page_cache_get_speculative() with disabled local interrupts.
It should be atomic enough.

So let's check for disabled interrupts in the VM_BUG_ON() condition
too, to resolve this.

( This got triggered by the conversion of the x86 GUP code to the
  generic GUP code. )

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: LKP <lkp@01.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170324114709.pcytvyb3d6ajux33@black.fi.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-28 08:23:27 +02:00
Documentation Merge branch 'linus' into x86/mm, to pick up a bugfix 2017-03-17 08:55:01 +01:00
arch x86: Convert the rest of the code to support p4d_t 2017-03-27 08:56:58 +02:00
block blk-mq-sched: don't run the queue async from blk_mq_try_issue_directly() 2017-03-14 11:51:59 -06:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto net: Work around lockdep limitation in sockets that use sockets 2017-03-09 18:23:27 -08:00
drivers Merge branch 'linus' into x86/mm, to pick up a bugfix 2017-03-17 08:55:01 +01:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs Merge branch 'x86/process' into x86/mm, to create new base for further patches 2017-03-23 08:28:19 +01:00
include mm: Fix false-positive VM_BUG_ON() in page_cache_{get,add}_speculative() 2017-03-28 08:23:27 +02:00
init Change get_random_{int,log} to use the CRNG used by /dev/urandom and 2017-03-11 09:08:47 -08:00
ipc Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-03-14 21:31:23 -07:00
lib mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
mm x86/mm/gup: Switch GUP to the generic get_user_page_fast() implementation 2017-03-18 09:48:03 +01:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-03-14 21:31:23 -07:00
samples Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-03 11:38:56 -08:00
scripts Merge branch 'akpm' (patches from Andrew) 2017-03-10 08:34:42 -08:00
security Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
sound scripts/spelling.txt: add "disble(d)" pattern and fix typo instances 2017-03-09 17:01:09 -08:00
tools selftests/x86/ldt_gdt_32: Work around a glibc sigaction() bug 2017-03-23 08:25:07 +01:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt KVM: arm/arm64: VGIC: Fix command handling while ITS being disabled 2017-03-07 15:44:08 +00:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.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 MAINTAINERS: usb251xb: remove reference inexistent file 2017-03-09 10:34:16 +01:00
Makefile Linux 4.11-rc2 2017-03-12 14:47:08 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README

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.