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| author |   Hugh Dickins <hughd@google.com> | 2018-07-20 17:53:45 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2018-07-21 12:50:46 -0700 |
| commit | e1f1b1572e8db87a56609fd05bef76f98f0e456a (patch) | |
| tree | 97c419c35f7bea38037c6ffa77017fa6ddf1232c /.get_maintainer.ignore | |
| parent | fat: fix memory allocation failure handling of match_strdup() (diff) | |
| download | linux-dev-e1f1b1572e8db87a56609fd05bef76f98f0e456a.tar.xz linux-dev-e1f1b1572e8db87a56609fd05bef76f98f0e456a.zip | |
mm/huge_memory.c: fix data loss when splitting a file pmd
__split_huge_pmd_locked() must check if the cleared huge pmd was dirty,
and propagate that to PageDirty: otherwise, data may be lost when a huge
tmpfs page is modified then split then reclaimed.
How has this taken so long to be noticed? Because there was no problem
when the huge page is written by a write system call (shmem_write_end()
calls set_page_dirty()), nor when the page is allocated for a write fault
(fault_dirty_shared_page() calls set_page_dirty()); but when allocated for
a read fault (which MAP_POPULATE simulates), no set_page_dirty().
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1807111741430.1106@eggly.anvils
Fixes: d21b9e57c74c ("thp: handle file pages in split_huge_pmd()")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Ashwin Chaugule <ashwinch@google.com>
Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: <stable@vger.kernel.org> [4.8+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '.get_maintainer.ignore')
0 files changed, 0 insertions, 0 deletions