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Linux kernel source tree for SHARP Brain series (PW-SH1 or later)
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Hugh Dickins 61168eafe0 mm, futex: fix shared futex pgoff on shmem huge page 
[ Upstream commit fe19bd3dae3d15d2fbfdb3de8839a6ea0fe94264 ]

If more than one futex is placed on a shmem huge page, it can happen
that waking the second wakes the first instead, and leaves the second
waiting: the key's shared.pgoff is wrong.

When 3.11 commit 13d60f4b6a ("futex: Take hugepages into account when
generating futex_key"), the only shared huge pages came from hugetlbfs,
and the code added to deal with its exceptional page->index was put into
hugetlb source.  Then that was missed when 4.8 added shmem huge pages.

page_to_pgoff() is what others use for this nowadays: except that, as
currently written, it gives the right answer on hugetlbfs head, but
nonsense on hugetlbfs tails.  Fix that by calling hugetlbfs-specific
hugetlb_basepage_index() on PageHuge tails as well as on head.

Yes, it's unconventional to declare hugetlb_basepage_index() there in
pagemap.h, rather than in hugetlb.h; but I do not expect anything but
page_to_pgoff() ever to need it.

[akpm@linux-foundation.org: give hugetlb_basepage_index() prototype the correct scope]

Link: https://lkml.kernel.org/r/b17d946b-d09-326e-b42a-52884c36df32@google.com
Fixes: 800d8c63b2 ("shmem: add huge pages support")
Reported-by: Neel Natu <neelnatu@google.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Zhang Yi <wetpzy@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Note on stable backport: leave redundant #include <linux/hugetlb.h>
in kernel/futex.c, to avoid conflict over the header files included.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 		2021-06-30 08:47:55 -04:00
Documentation mm/slub: clarify verification reporting 2021-06-23 14:41:30 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch PCI: Add AMD RS690 quirk to enable 64-bit DMA 2021-06-30 08:47:49 -04:00
block blk-mq: Swap two calls in blk_mq_exit_queue() 2021-05-19 10:08:30 +02:00
certs certs: Fix blacklist flag type confusion 2021-03-04 10:26:29 +01:00
crypto crypto: rng - fix crypto_rng_reset() refcounting when !CRYPTO_STATS 2021-05-11 14:04:15 +02:00
drivers i2c: robotfuzz-osif: fix control-request directions 2021-06-30 08:47:50 -04:00
fs nilfs2: fix memory leak in nilfs_sysfs_delete_device_group 2021-06-30 08:47:50 -04:00
include mm, futex: fix shared futex pgoff on shmem huge page 2021-06-30 08:47:55 -04:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel mm, futex: fix shared futex pgoff on shmem huge page 2021-06-30 08:47:55 -04:00
lib lib/lz4: explicitly support in-place decompression 2021-06-10 13:37:16 +02:00
mm mm, futex: fix shared futex pgoff on shmem huge page 2021-06-30 08:47:55 -04:00
net net/packet: annotate accesses to po->ifindex 2021-06-30 08:47:48 -04:00
samples samples: vfio-mdev: fix error handing in mdpy_fb_probe() 2021-06-10 13:37:03 +02:00
scripts recordmcount: Correct st_shndx handling 2021-06-30 08:47:49 -04:00
security security: commoncap: fix -Wstringop-overread warning 2021-05-11 14:04:16 +02:00
sound ASoC: rt5659: Fix the lost powers for the HDA header 2021-06-23 14:41:27 +02:00
tools KVM: selftests: Fix kvm_check_cap() assertion 2021-06-30 08:47:49 -04:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: do not allow mapping valid but non-reference-counted pages 2021-06-30 08:47:50 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.128 2021-06-23 14:41:32 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -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.

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.