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Filename Latest commit message Latest commit date
Hugh Dickins 2d077d4b59 mm/huge_memory.c: __split_huge_page() use atomic ClearPageDirty()
Swapping load on huge=always tmpfs (with khugepaged tuned up to be very
eager, but I'm not sure that is relevant) soon hung uninterruptibly,
waiting for page lock in shmem_getpage_gfp()'s find_lock_entry(), most
often when "cp -a" was trying to write to a smallish file.  Debug showed
that the page in question was not locked, and page->mapping NULL by now,
but page->index consistent with having been in a huge page before.

Reproduced in minutes on a 4.15 kernel, even with 4.17's 605ca5ede7
("mm/huge_memory.c: reorder operations in __split_huge_page_tail()") added
in; but took hours to reproduce on a 4.17 kernel (no idea why).

The culprit proved to be the __ClearPageDirty() on tails beyond i_size in
__split_huge_page(): the non-atomic __bitoperation may have been safe when
4.8's baa355fd33 ("thp: file pages support for split_huge_page()")
introduced it, but liable to erase PageWaiters after 4.10's 6290602709
("mm: add PageWaiters indicating tasks are waiting for a page bit").

Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1805291841070.3197@eggly.anvils
Fixes: 6290602709 ("mm: add PageWaiters indicating tasks are waiting for a page bit")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-02 09:33:47 -07:00
arch Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2018-05-30 10:30:30 -05:00
block
certs
crypto
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-05-25 19:54:42 -07:00
drivers platform-drivers-x86 for v4.17-4 2018-05-31 09:39:57 -05:00
firmware
fs Merge tag 'afs-fixes-20180529' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs 2018-05-29 15:30:16 -05:00
include Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-05-26 13:10:16 -07:00
init init/main.c: include <linux/mem_encrypt.h> 2018-05-25 18:12:11 -07:00
ipc ipc/shm: fix shmat() nil address after round-down when remapping 2018-05-25 18:12:11 -07:00
kernel While writing selftests for a new feature, I triggered two existing 2018-05-29 07:28:48 -05:00
lib idr: fix invalid ptr dereference on item delete 2018-05-25 18:12:10 -07:00
LICENSES
mm mm/huge_memory.c: __split_huge_page() use atomic ClearPageDirty() 2018-06-02 09:33:47 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-05-25 19:54:42 -07:00
samples x86/cpufeature: Guard asm_volatile_goto usage for BPF compilation 2018-05-13 21:49:14 +02:00
scripts checkpatch: fix macro argument precedence test 2018-05-25 18:12:11 -07:00
security selinux/stable-4.17 PR 20180530 2018-05-30 16:35:07 -05:00
sound ALSA: hda - Fix runtime PM 2018-05-24 20:16:47 +02:00
tools Merge branch 'akpm' (patches from Andrew) 2018-05-25 20:24:28 -07:00
usr
virt KVM: arm/arm64: VGIC/ITS save/restore: protect kvm_read_guest() calls 2018-05-15 13:36:53 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Merge branch 'akpm' (patches from Andrew) 2018-05-25 20:24:28 -07:00
Makefile Linux 4.17-rc7 2018-05-27 13:01:47 -07:00
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.