SLUB: Fix memory leak by not reusing cpu_slab
Fix the memory leak that may occur when we attempt to reuse a cpu_slab that was allocated while we reenabled interrupts in order to be able to grow a slab cache. The per cpu freelist may contain objects and in that situation we may overwrite the per cpu freelist pointer loosing objects. This only occurs if we find that the concurrently allocated slab fits our allocation needs. If we simply always deactivate the slab then the freelist will be properly reintegrated and the memory leak will go away. Signed-off-by: Christoph Lameter <clameter@sgi.com> Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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aac9e28d2f
commit
05aa345034
20
mm/slub.c
20
mm/slub.c
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@ -1511,26 +1511,8 @@ new_slab:
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if (new) {
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if (new) {
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c = get_cpu_slab(s, smp_processor_id());
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c = get_cpu_slab(s, smp_processor_id());
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if (c->page) {
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if (c->page)
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/*
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* Someone else populated the cpu_slab while we
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* enabled interrupts, or we have gotten scheduled
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* on another cpu. The page may not be on the
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* requested node even if __GFP_THISNODE was
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* specified. So we need to recheck.
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*/
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if (node_match(c, node)) {
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/*
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* Current cpuslab is acceptable and we
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* want the current one since its cache hot
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*/
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discard_slab(s, new);
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slab_lock(c->page);
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goto load_freelist;
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}
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/* New slab does not fit our expectations */
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flush_slab(s, c);
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flush_slab(s, c);
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}
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slab_lock(new);
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slab_lock(new);
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SetSlabFrozen(new);
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SetSlabFrozen(new);
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c->page = new;
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c->page = new;
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