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author | Hugh Dickins <hughd@google.com> | 2014-06-23 13:22:05 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-06-23 16:47:44 -0700 |
commit | 5338a9372234f8b782c7d78f0355e1cb21d02468 (patch) | |
tree | 038ed1c19e7434f0ec4c6556b7367798348882ec /mm/ksm.c | |
parent | ed235875e2ca983197831337a986f0517074e1a0 (diff) | |
download | op-kernel-dev-5338a9372234f8b782c7d78f0355e1cb21d02468.zip op-kernel-dev-5338a9372234f8b782c7d78f0355e1cb21d02468.tar.gz |
mm: thp: fix DEBUG_PAGEALLOC oops in copy_page_rep()
Trinity has for over a year been reporting a CONFIG_DEBUG_PAGEALLOC oops
in copy_page_rep() called from copy_user_huge_page() called from
do_huge_pmd_wp_page().
I believe this is a DEBUG_PAGEALLOC false positive, due to the source
page being split, and a tail page freed, while copy is in progress; and
not a problem without DEBUG_PAGEALLOC, since the pmd_same() check will
prevent a miscopy from being made visible.
Fix by adding get_user_huge_page() and put_user_huge_page(): reducing to
the usual get_page() and put_page() on head page in the usual config;
but get and put references to all of the tail pages when
DEBUG_PAGEALLOC.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/ksm.c')
0 files changed, 0 insertions, 0 deletions