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Filename Latest commit message Latest commit date
Mike Kravetz 5dd34ee9ab hugetlb: fix update_and_free_page contig page struct assumption
commit dbfee5aee7e54f83d96ceb8e3e80717fac62ad63 upstream.

page structs are not guaranteed to be contiguous for gigantic pages.  The
routine update_and_free_page can encounter a gigantic page, yet it assumes
page structs are contiguous when setting page flags in subpages.

If update_and_free_page encounters non-contiguous page structs, we can see
“BUG: Bad page state in process …” errors.

Non-contiguous page structs are generally not an issue.  However, they can
exist with a specific kernel configuration and hotplug operations.  For
example: Configure the kernel with CONFIG_SPARSEMEM and
!CONFIG_SPARSEMEM_VMEMMAP.  Then, hotplug add memory for the area where
the gigantic page will be allocated.  Zi Yan outlined steps to reproduce
here [1].

[1] https://lore.kernel.org/linux-mm/16F7C58B-4D79-41C5-9B64-A1A1628F4AF2@nvidia.com/

Link: https://lkml.kernel.org/r/20210217184926.33567-1-mike.kravetz@oracle.com
Fixes: 944d9fec8d ("hugetlb: add support for gigantic page allocation at runtime")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-04 10:26:48 +01:00
arch x86: fix seq_file iteration for pat/memtype.c 2021-03-04 10:26:48 +01:00
block blk-settings: align max_sectors on "logical_block_size" boundary 2021-03-04 10:26:40 +01:00
certs certs: Fix blacklist flag type confusion 2021-03-04 10:26:29 +01:00
crypto crypto: ecdh_helper - Ensure 'len >= secret.len' in decode_key() 2021-03-04 10:26:25 +01:00
Documentation seq_file: document how per-entry resources are managed. 2021-03-04 10:26:48 +01:00
drivers mtd: spi-nor: hisi-sfc: Put child node np on error path 2021-03-04 10:26:48 +01:00
fs fs/affs: release old buffer head on error path 2021-03-04 10:26:48 +01:00
include rcu/nocb: Perform deferred wake up before last idle's need_resched() check 2021-03-04 10:26:47 +01:00
init fgraph: Initialize tracing_graph_pause at task creation 2021-02-10 09:25:29 +01:00
ipc
kernel rcu/nocb: Perform deferred wake up before last idle's need_resched() check 2021-03-04 10:26:47 +01:00
lib udp: fix skb_copy_and_csum_datagram with odd segment sizes 2021-02-17 10:35:19 +01:00
LICENSES
mm hugetlb: fix update_and_free_page contig page struct assumption 2021-03-04 10:26:48 +01:00
net bpf: Fix bpf_fib_lookup helper MTU check for SKB ctx 2021-03-04 10:26:17 +01:00
samples samples: bpf: Fix lwt_len_hist reusing previous BPF map 2020-12-30 11:51:12 +01:00
scripts scripts/recordmcount.pl: support big endian for ARCH sh 2021-02-26 10:10:28 +01:00
security KEYS: trusted: Fix migratable=1 failing 2021-03-04 10:26:44 +01:00
sound ALSA: hda/realtek: modify EAPD in the ALC886 2021-03-04 10:26:42 +01:00
tools perf test: Fix unaligned access in sample parsing test 2021-03-04 10:26:35 +01:00
usr
virt KVM: Use kvm_pfn_t for local PFN variable in hva_to_pfn_remapped() 2021-02-26 10:10:28 +01:00
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Makefile Linux 5.4.101 2021-02-26 10:10:28 +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.