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| author |   Linus Torvalds <torvalds@woody.osdl.org> | 2006-12-16 09:44:32 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.osdl.org> | 2006-12-16 09:44:32 -0800 |
| commit | 2f77d107050abc14bc393b34bdb7b91cf670c250 (patch) | |
| tree | 6651586fb1b10f60cd6acdb3222bafac9c2d7aa8 /kernel | |
| parent | Fix "delayed_work_pending()" macro expansion (diff) | |
| download | linux-dev-2f77d107050abc14bc393b34bdb7b91cf670c250.tar.xz linux-dev-2f77d107050abc14bc393b34bdb7b91cf670c250.zip | |
Fix incorrect user space access locking in mincore()
Doug Chapman noticed that mincore() will doa "copy_to_user()" of the
result while holding the mmap semaphore for reading, which is a big
no-no. While a recursive read-lock on a semaphore in the case of a page
fault happens to work, we don't actually allow them due to deadlock
schenarios with writers due to fairness issues.
Doug and Marcel sent in a patch to fix it, but I decided to just rewrite
the mess instead - not just fixing the locking problem, but making the
code smaller and (imho) much easier to understand.
Cc: Doug Chapman <dchapman@redhat.com>
Cc: Marcel Holtmann <holtmann@redhat.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
0 files changed, 0 insertions, 0 deletions