diff options
author | Hugh Dickins <hugh@veritas.com> | 2005-10-29 18:16:27 -0700 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-10-29 21:40:40 -0700 |
commit | 705e87c0c3c38424f7f30556c85bc20e808d2f59 (patch) | |
tree | 7a237e6266f4801385e1226cc497b47e3a2458bd /mm/mmap.c | |
parent | 8f4e2101fd7df9031a754eedb82e2060b51f8c45 (diff) |
[PATCH] mm: pte_offset_map_lock loops
Convert those common loops using page_table_lock on the outside and
pte_offset_map within to use just pte_offset_map_lock within instead.
These all hold mmap_sem (some exclusively, some not), so at no level can a
page table be whipped away from beneath them. But whereas pte_alloc loops
tested with the "atomic" pmd_present, these loops are testing with pmd_none,
which on i386 PAE tests both lower and upper halves.
That's now unsafe, so add a cast into pmd_none to test only the vital lower
half: we lose a little sensitivity to a corrupt middle directory, but not
enough to worry about. It appears that i386 and UML were the only
architectures vulnerable in this way, and pgd and pud no problem.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/mmap.c')
0 files changed, 0 insertions, 0 deletions