I use the btree which pickes up the latest version of kernel source 3.14-rc2 in my own module. When the btree module is removed, a warning arised:
kmem_cache_destroy btree_node: Slab cache still has objects CPU: 13 PID: 9150 Comm: rmmod Tainted: GF O 3.14.0-rc2 #1 Hardware name: Inspur NF5270M3/NF5270M3, BIOS CHEETAH_2.1.3 09/10/2013 ffff881ff8643b18 ffff881ffdc23ea8 ffffffff815a4ecc 0000000000000000 ffff881ff8643ac0 ffff881ffdc23ec8 ffffffff811610df 0000000000000880 ffffffffa057da60 ffff881ffdc23ed8 ffffffffa057d57c ffff881ffdc23f78 Call Trace: [<ffffffff815a4ecc>] dump_stack+0x49/0x5d [<ffffffff811610df>] kmem_cache_destroy+0xcf/0xe0 [<ffffffffa057d57c>] btree_module_exit+0x10/0x12 [btree] [<ffffffff810d7948>] SyS_delete_module+0x198/0x1f0 [<ffffffff815aac89>] ? retint_swapgs+0xe/0x13 [<ffffffff810a561d>] ? trace_hardirqs_on_caller+0xfd/0x1c0 [<ffffffff812addde>] ? trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff815b3652>] system_call_fastpath+0x16/0x1b The cause is that it doesn't release the last btree node, when height = 1 and fill = 1. Signed-off-by: Minfei Huang <[email protected]> CC: Joern Engel <[email protected]> CC: Johannes Berg <[email protected]> --- lib/btree.c | 12 ++++++++++++ 1 files changed, 12 insertions(+), 0 deletions(-) diff --git a/lib/btree.c b/lib/btree.c index f9a4846..fd17d26 100644 --- a/lib/btree.c +++ b/lib/btree.c @@ -444,6 +444,16 @@ static void btree_shrink(struct btree_head *head, struct btree_geo *geo) mempool_free(node, head->mempool); } +static void btree_shrink_head(struct btree_head *head) +{ + if (head->height != 1) + return; + + mempool_free(head->node, head->mempool); + head->node = NULL; + head->height--; +} + static int btree_insert_level(struct btree_head *head, struct btree_geo *geo, unsigned long *key, void *val, int level, gfp_t gfp) @@ -620,6 +630,8 @@ static void *btree_remove_level(struct btree_head *head, struct btree_geo *geo, rebalance(head, geo, key, level, node, fill - 1); else if (fill - 1 == 1) btree_shrink(head, geo); + else if (fill - 1 == 0) + btree_shrink_head(head); } return ret; -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
