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Filename Latest commit message Latest commit date
Baolin Wang 176ba4c19d mm/hugetlb: fix races when looking up a CONT-PTE/PMD size hugetlb page
commit fac35ba763ed07ba93154c95ffc0c4a55023707f upstream.

On some architectures (like ARM64), it can support CONT-PTE/PMD size
hugetlb, which means it can support not only PMD/PUD size hugetlb (2M and
1G), but also CONT-PTE/PMD size(64K and 32M) if a 4K page size specified.

So when looking up a CONT-PTE size hugetlb page by follow_page(), it will
use pte_offset_map_lock() to get the pte entry lock for the CONT-PTE size
hugetlb in follow_page_pte().  However this pte entry lock is incorrect
for the CONT-PTE size hugetlb, since we should use huge_pte_lock() to get
the correct lock, which is mm->page_table_lock.

That means the pte entry of the CONT-PTE size hugetlb under current pte
lock is unstable in follow_page_pte(), we can continue to migrate or
poison the pte entry of the CONT-PTE size hugetlb, which can cause some
potential race issues, even though they are under the 'pte lock'.

For example, suppose thread A is trying to look up a CONT-PTE size hugetlb
page by move_pages() syscall under the lock, however antoher thread B can
migrate the CONT-PTE hugetlb page at the same time, which will cause
thread A to get an incorrect page, if thread A also wants to do page
migration, then data inconsistency error occurs.

Moreover we have the same issue for CONT-PMD size hugetlb in
follow_huge_pmd().

To fix above issues, rename the follow_huge_pmd() as follow_huge_pmd_pte()
to handle PMD and PTE level size hugetlb, which uses huge_pte_lock() to
get the correct pte entry lock to make the pte entry stable.

Mike said:

Support for CONT_PMD/_PTE was added with bb9dd3df8e ("arm64: hugetlb:
refactor find_num_contig()").  Patch series "Support for contiguous pte
hugepages", v4.  However, I do not believe these code paths were
executed until migration support was added with 5480280d3f ("arm64/mm:
enable HugeTLB migration for contiguous bit HugeTLB pages") I would go
with 5480280d3f for the Fixes: targe.

Link: https://lkml.kernel.org/r/635f43bdd85ac2615a58405da82b4d33c6e5eb05.1662017562.git.baolin.wang@linux.alibaba.com
Fixes: 5480280d3f ("arm64/mm: enable HugeTLB migration for contiguous bit HugeTLB pages")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[5.4: Fixup contextual diffs before pin_user_pages()]
Signed-off-by: Samuel Mendoza-Jonas <samjonas@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-12-19 12:24:15 +01:00
arch x86/smpboot: Move rcu_cpu_starting() earlier 2022-12-19 12:24:15 +01:00
block block, bfq: fix null pointer dereference in bfq_bio_bfqg() 2022-12-08 11:22:57 +01:00
certs
crypto
Documentation docs: update mediator contact information in CoC doc 2022-11-25 17:42:20 +01:00
drivers can: esd_usb: Allow REC and TEC to return to zero 2022-12-14 11:30:48 +01:00
fs btrfs: send: avoid unaligned encoded writes when attempting to clone range 2022-12-14 11:30:41 +01:00
include mm/hugetlb: fix races when looking up a CONT-PTE/PMD size hugetlb page 2022-12-19 12:24:15 +01:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-12-08 11:22:59 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel memcg: fix possible use-after-free in memcg_write_event_control() 2022-12-14 11:30:43 +01:00
lib Kconfig.debug: provide a little extra FRAME_WARN leeway when KASAN is enabled 2022-12-08 11:23:05 +01:00
LICENSES
mm mm/hugetlb: fix races when looking up a CONT-PTE/PMD size hugetlb page 2022-12-19 12:24:15 +01:00
net net: bpf: Allow TC programs to call BPF_FUNC_skb_change_head 2022-12-19 12:24:15 +01:00
samples
scripts scripts/faddr2line: Fix regression in name resolution on ppc64le 2022-12-08 11:23:02 +01:00
security
sound ASoC: soc-pcm: Add NULL check in BE reparenting 2022-12-14 11:30:41 +01:00
tools ipv4: Fix incorrect route flushing when source address is deleted 2022-12-14 11:30:47 +01:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.227 2022-12-14 11:30:48 +01:00
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.