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Peter Xu 734654ae79 mm/hugetlb: fix calculation of adjust_range_if_pmd_sharing_possible 
commit 75802ca663 upstream.

This is found by code observation only.

Firstly, the worst case scenario should assume the whole range was covered
by pmd sharing.  The old algorithm might not work as expected for ranges
like (1g-2m, 1g+2m), where the adjusted range should be (0, 1g+2m) but the
expected range should be (0, 2g).

Since at it, remove the loop since it should not be required.  With that,
the new code should be faster too when the invalidating range is huge.

Mike said:

: With range (1g-2m, 1g+2m) within a vma (0, 2g) the existing code will only
: adjust to (0, 1g+2m) which is incorrect.
:
: We should cc stable.  The original reason for adjusting the range was to
: prevent data corruption (getting wrong page).  Since the range is not
: always adjusted correctly, the potential for corruption still exists.
:
: However, I am fairly confident that adjust_range_if_pmd_sharing_possible
: is only gong to be called in two cases:
:
: 1) for a single page
: 2) for range == entire vma
:
: In those cases, the current code should produce the correct results.
:
: To be safe, let's just cc stable.

Fixes: 017b1660df ("mm: migration: fix migration of huge PMD shared pages")
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200730201636.74778-1-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-26 10:31:06 +02:00
arch powerpc/pseries: Do not initiate shutdown when system is running on UPS 2020-08-26 10:31:06 +02:00
block block: release bip in a right way in error path 2020-07-16 08:17:23 +02:00
certs
crypto
Documentation dt-bindings: iio: io-channel-mux: Fix compatible string in example code 2020-08-21 11:05:30 +02:00
drivers efi: add missed destroy_workqueue when efisubsys_init fails 2020-08-26 10:31:06 +02:00
firmware
fs do_epoll_ctl(): clean the failure exits up a bit 2020-08-26 10:31:06 +02:00
include iommu/vt-d: Enforce PASID devTLB field mask 2020-08-21 11:05:36 +02:00
init printk: queue wake_up_klogd irq_work only if per-CPU areas are ready 2020-07-22 09:32:13 +02:00
ipc
kernel kthread: Do not preempt current task if it is going to call schedule() 2020-08-26 10:31:00 +02:00
lib test_kmod: avoid potential double free in trigger_config_run_type() 2020-08-21 11:05:38 +02:00
LICENSES
mm mm/hugetlb: fix calculation of adjust_range_if_pmd_sharing_possible 2020-08-26 10:31:06 +02:00
net svcrdma: Fix another Receive buffer leak 2020-08-26 10:31:01 +02:00
samples
scripts kconfig: qconf: fix signal connection to invalid slots 2020-08-26 10:31:04 +02:00
security Smack: prevent underflow in smk_set_cipso() 2020-08-19 08:14:59 +02:00
sound ASoC: intel: Fix memleak in sst_media_open 2020-08-26 10:31:04 +02:00
tools tools/testing/selftests/cgroup/cgroup_util.c: cg_read_strcmp: fix null pointer dereference 2020-08-26 10:31:02 +02:00
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Makefile Linux 4.19.141 2020-08-21 11:05:39 +02:00
README

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.