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authorChristoph Lameter <clameter@sgi.com>2007-11-05 14:31:58 -0500
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-11-05 14:37:12 -0500
commit05aa345034de6ae9c77fb93f6a796013641d57d5 (patch)
tree3522f909f91e14b86e8dc0cedcb8e17bc0901bbe /mm
parentaac9e28d2f3d3c1eacc4114d685864a2a6423b80 (diff)
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>
Diffstat (limited to 'mm')
-rw-r--r--mm/slub.c20
1 files changed, 1 insertions, 19 deletions
diff --git a/mm/slub.c b/mm/slub.c
index bcdb2c8941a5..84f59fde1a10 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1511,26 +1511,8 @@ new_slab:
1511 1511
1512 if (new) { 1512 if (new) {
1513 c = get_cpu_slab(s, smp_processor_id()); 1513 c = get_cpu_slab(s, smp_processor_id());
1514 if (c->page) { 1514 if (c->page)
1515 /*
1516 * Someone else populated the cpu_slab while we
1517 * enabled interrupts, or we have gotten scheduled
1518 * on another cpu. The page may not be on the
1519 * requested node even if __GFP_THISNODE was
1520 * specified. So we need to recheck.
1521 */
1522 if (node_match(c, node)) {
1523 /*
1524 * Current cpuslab is acceptable and we
1525 * want the current one since its cache hot
1526 */
1527 discard_slab(s, new);
1528 slab_lock(c->page);
1529 goto load_freelist;
1530 }
1531 /* New slab does not fit our expectations */
1532 flush_slab(s, c); 1515 flush_slab(s, c);
1533 }
1534 slab_lock(new); 1516 slab_lock(new);
1535 SetSlabFrozen(new); 1517 SetSlabFrozen(new);
1536 c->page = new; 1518 c->page = new;