Original code may get a stall value when overwriting the whole range on a maple tree with only root node. The reason is we didn't set the only root node dead during destroy. Add a test case to verify this is not recreated. Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx> CC: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> --- tools/testing/radix-tree/maple.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c index bc30050227fd..1e293e4d856d 100644 --- a/tools/testing/radix-tree/maple.c +++ b/tools/testing/radix-tree/maple.c @@ -35256,6 +35256,30 @@ static noinline void __init check_rcu_simulated(struct maple_tree *mt) MT_BUG_ON(mt, mas_prev(&mas_reader, 0) != xa_mk_value(val)); rcu_read_unlock(); + /* Clear out tree & create one with only root node */ + mas_lock(&mas_writer); + mas_set_range(&mas_writer, 0, ULONG_MAX); + mas_store_gfp(&mas_writer, NULL, GFP_KERNEL); + mas_set_range(&mas_writer, 0, 0); + for (i = 0; i <= 5; i++) { + mas_writer.index = i * 10; + mas_writer.last = i * 10 + 5; + mas_store_gfp(&mas_writer, xa_mk_value(i), GFP_KERNEL); + } + mas_unlock(&mas_writer); + target = 10; + mas_set_range(&mas_reader, target, target); + rcu_read_lock(); + MT_BUG_ON(mt, mas_walk(&mas_reader) != xa_mk_value(target/10)); + + /* Overwrite the whole range */ + mas_lock(&mas_writer); + mas_set_range(&mas_writer, 0, ULONG_MAX); + mas_store_gfp(&mas_writer, xa_mk_value(val), GFP_KERNEL); + mas_unlock(&mas_writer); + MT_BUG_ON(mt, mas_walk(&mas_reader) != xa_mk_value(val)); + rcu_read_unlock(); + rcu_unregister_thread(); } -- 2.34.1