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author | Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> | 2010-11-24 12:57:13 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-11-25 06:50:46 +0900 |
commit | ea251c1d5c481cda1cf6b0c9e4965f04a6cf2ffc (patch) | |
tree | 989753f439461fb333432761b8bf39d408572c62 /.mailmap | |
parent | 5f0af70a25593a9d53b87bc8d31902fb7cc63e40 (diff) | |
download | op-kernel-dev-ea251c1d5c481cda1cf6b0c9e4965f04a6cf2ffc.zip op-kernel-dev-ea251c1d5c481cda1cf6b0c9e4965f04a6cf2ffc.tar.gz |
pagemap: set pagemap walk limit to PMD boundary
Currently one pagemap_read() call walks in PAGEMAP_WALK_SIZE bytes (== 512
pages.) But there is a corner case where walk_pmd_range() accidentally
runs over a VMA associated with a hugetlbfs file.
For example, when a process has mappings to VMAs as shown below:
# cat /proc/<pid>/maps
...
3a58f6d000-3a58f72000 rw-p 00000000 00:00 0
7fbd51853000-7fbd51855000 rw-p 00000000 00:00 0
7fbd5186c000-7fbd5186e000 rw-p 00000000 00:00 0
7fbd51a00000-7fbd51c00000 rw-s 00000000 00:12 8614 /hugepages/test
then pagemap_read() goes into walk_pmd_range() path and walks in the range
0x7fbd51853000-0x7fbd51a53000, but the hugetlbfs VMA should be handled by
walk_hugetlb_range(). Otherwise PMD for the hugepage is considered bad
and cleared, which causes undesirable results.
This patch fixes it by separating pagemap walk range into one PMD.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '.mailmap')
0 files changed, 0 insertions, 0 deletions