The patch titled Subject: test_maple_tree: add more testing for mas_empty_area() has been added to the -mm mm-hotfixes-unstable branch. Its filename is test_maple_tree-add-more-testing-for-mas_empty_area.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: "Liam R. Howlett" Liam.Howlett@oracle.com Subject: test_maple_tree: add more testing for mas_empty_area() Date: Tue, 7 Mar 2023 13:02:47 -0500

Test robust filling of an entire area of the tree, then test one beyond. This is to test the walking back up the tree at the end of nodes and error condition. Test inspired by the reproducer code provided by Snild Dolkow.

The last test in the function tests for the case of a corrupted maple state caused by the incorrect limits set during mas_skip_node(). There needs to be a gap in the second last child and last child, but the search must rule out the second last child's gap. This would avoid correcting the maple state to the correct max limit and return an error.

Link: https://lkml.kernel.org/r/20230307180247.2220303-3-Liam.Howlett@oracle.com Cc: Snild Dolkow snild@sony.com Link: https://lore.kernel.org/linux-mm/cb8dc31a-fef2-1d09-f133-e9f7b9f9e77a@sony.c... Fixes: e15e06a83923 ("lib/test_maple_tree: add testing for maple tree") Signed-off-by: Liam R. Howlett Liam.Howlett@oracle.com Cc: Peng Zhang zhangpeng.00@bytedance.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

lib/test_maple_tree.c | 48 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+)

--- a/lib/test_maple_tree.c~test_maple_tree-add-more-testing-for-mas_empty_area +++ a/lib/test_maple_tree.c @@ -2670,6 +2670,49 @@ static noinline void check_empty_area_wi rcu_read_unlock(); }

+static noinline void check_empty_area_fill(struct maple_tree *mt) +{ + const unsigned long max = 0x25D78000; + unsigned long size; + int loop, shift; + MA_STATE(mas, mt, 0, 0); + + mt_set_non_kernel(99999); + for (shift = 12; shift <= 16; shift++) { + loop = 5000; + size = 1 << shift; + while (loop--) { + mas_set(&mas, 0); + mas_lock(&mas); + MT_BUG_ON(mt, mas_empty_area(&mas, 0, max, size) != 0); + MT_BUG_ON(mt, mas.last != mas.index + size - 1); + mas_store_gfp(&mas, (void *)size, GFP_KERNEL); + mas_unlock(&mas); + mas_reset(&mas); + } + } + + /* No space left. */ + size = 0x1000; + rcu_read_lock(); + MT_BUG_ON(mt, mas_empty_area(&mas, 0, max, size) != -EBUSY); + rcu_read_unlock(); + + /* Fill a depth 3 node to the maximum */ + for (unsigned long i = 629440511; i <= 629440800; i += 6) + mtree_store_range(mt, i, i + 5, (void *)i, GFP_KERNEL); + /* Make space in the second-last depth 4 node */ + mtree_erase(mt, 631668735); + /* Make space in the last depth 4 node */ + mtree_erase(mt, 629506047); + mas_reset(&mas); + /* Search from just after the gap in the second-last depth 4 */ + rcu_read_lock(); + MT_BUG_ON(mt, mas_empty_area(&mas, 629506048, 690000000, 0x5000) != 0); + rcu_read_unlock(); + mt_set_non_kernel(0); +} + static DEFINE_MTREE(tree); static int maple_tree_seed(void) { @@ -2926,6 +2969,11 @@ static int maple_tree_seed(void) check_empty_area_window(&tree); mtree_destroy(&tree);

+ mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE); + check_empty_area_fill(&tree); + mtree_destroy(&tree); + + #if defined(BENCH) skip: #endif _

Patches currently in -mm which might be from Liam.Howlett@oracle.com are

maple_tree-fix-mas_skip_node-end-slot-detection.patch test_maple_tree-add-more-testing-for-mas_empty_area.patch maple_tree-be-more-cautious-about-dead-nodes.patch maple_tree-detect-dead-nodes-in-mas_start.patch maple_tree-fix-freeing-of-nodes-in-rcu-mode.patch maple_tree-remove-extra-smp_wmb-from-mas_dead_leaves.patch maple_tree-fix-write-memory-barrier-of-nodes-once-dead-for-rcu-mode.patch maple_tree-add-smp_rmb-to-dead-node-detection.patch maple_tree-add-rcu-lock-checking-to-rcu-callback-functions.patch mm-enable-maple-tree-rcu-mode-by-default.patch