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| author | Vitaly Wool <vitalywool@gmail.com> | 2017-04-13 14:56:14 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-04-13 18:24:20 -0700 |
| commit | 76e32a2a084ed71b48179023cd8fdb3787c8a6ad (patch) | |
| tree | d0a2cb8e6addcbdcb946192f27243eef0bb7ee3c /mm/huge_memory.c | |
| parent | 2760078203a6b46b96307f4b06030ab0b801c97e (diff) | |
| download | op-kernel-dev-76e32a2a084ed71b48179023cd8fdb3787c8a6ad.zip op-kernel-dev-76e32a2a084ed71b48179023cd8fdb3787c8a6ad.tar.gz | |
z3fold: fix page locking in z3fold_alloc()
Stress testing of the current z3fold implementation on a 8-core system
revealed it was possible that a z3fold page deleted from its unbuddied
list in z3fold_alloc() would be put on another unbuddied list by
z3fold_free() while z3fold_alloc() is still processing it. This has
been introduced with commit 5a27aa822 ("z3fold: add kref refcounting")
due to the removal of special handling of a z3fold page not on any list
in z3fold_free().
To fix this, the z3fold page lock should be taken in z3fold_alloc()
before the pool lock is released. To avoid deadlocking, we just try to
lock the page as soon as we get a hold of it, and if trylock fails, we
drop this page and take the next one.
Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: <Oleksiy.Avramchenko@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/huge_memory.c')
0 files changed, 0 insertions, 0 deletions
