From c13af03de46ba27674dd9fb31a17c0d480081139 Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" Date: Mon, 27 Feb 2023 09:36:04 -0800 Subject: maple_tree: fix write memory barrier of nodes once dead for RCU mode During the development of the maple tree, the strategy of freeing multiple nodes changed and, in the process, the pivots were reused to store pointers to dead nodes. To ensure the readers see accurate pivots, the writers need to mark the nodes as dead and call smp_wmb() to ensure any readers can identify the node as dead before using the pivot values. There were two places where the old method of marking the node as dead without smp_wmb() were being used, which resulted in RCU readers seeing the wrong pivot value before seeing the node was dead. Fix this race condition by using mte_set_node_dead() which has the smp_wmb() call to ensure the race is closed. Add a WARN_ON() to the ma_free_rcu() call to ensure all nodes being freed are marked as dead to ensure there are no other call paths besides the two updated paths. This is necessary for the RCU mode of the maple tree. Link: https://lkml.kernel.org/r/20230227173632.3292573-6-surenb@google.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett Signed-off-by: Suren Baghdasaryan Cc: Signed-off-by: Andrew Morton --- tools/testing/radix-tree/maple.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'tools/testing/radix-tree/maple.c') diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c index 958ee9bdb316..4c89ff333f6f 100644 --- a/tools/testing/radix-tree/maple.c +++ b/tools/testing/radix-tree/maple.c @@ -108,6 +108,7 @@ static noinline void check_new_node(struct maple_tree *mt) MT_BUG_ON(mt, mn->slot[1] != NULL); MT_BUG_ON(mt, mas_allocated(&mas) != 0); + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); mas.node = MAS_START; mas_nomem(&mas, GFP_KERNEL); @@ -160,6 +161,7 @@ static noinline void check_new_node(struct maple_tree *mt) MT_BUG_ON(mt, mas_allocated(&mas) != i); MT_BUG_ON(mt, !mn); MT_BUG_ON(mt, not_empty(mn)); + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); } @@ -192,6 +194,7 @@ static noinline void check_new_node(struct maple_tree *mt) MT_BUG_ON(mt, not_empty(mn)); MT_BUG_ON(mt, mas_allocated(&mas) != i - 1); MT_BUG_ON(mt, !mn); + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); } @@ -210,6 +213,7 @@ static noinline void check_new_node(struct maple_tree *mt) mn = mas_pop_node(&mas); MT_BUG_ON(mt, not_empty(mn)); MT_BUG_ON(mt, mas_allocated(&mas) != j - 1); + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); } MT_BUG_ON(mt, mas_allocated(&mas) != 0); @@ -233,6 +237,7 @@ static noinline void check_new_node(struct maple_tree *mt) MT_BUG_ON(mt, mas_allocated(&mas) != i - j); mn = mas_pop_node(&mas); MT_BUG_ON(mt, not_empty(mn)); + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); MT_BUG_ON(mt, mas_allocated(&mas) != i - j - 1); } @@ -269,6 +274,7 @@ static noinline void check_new_node(struct maple_tree *mt) mn = mas_pop_node(&mas); /* get the next node. */ MT_BUG_ON(mt, mn == NULL); MT_BUG_ON(mt, not_empty(mn)); + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); } MT_BUG_ON(mt, mas_allocated(&mas) != 0); @@ -294,6 +300,7 @@ static noinline void check_new_node(struct maple_tree *mt) mn = mas_pop_node(&mas2); /* get the next node. */ MT_BUG_ON(mt, mn == NULL); MT_BUG_ON(mt, not_empty(mn)); + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); } MT_BUG_ON(mt, mas_allocated(&mas2) != 0); @@ -334,10 +341,12 @@ static noinline void check_new_node(struct maple_tree *mt) MT_BUG_ON(mt, mas_allocated(&mas) != MAPLE_ALLOC_SLOTS + 2); mn = mas_pop_node(&mas); MT_BUG_ON(mt, not_empty(mn)); + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); for (i = 1; i <= MAPLE_ALLOC_SLOTS + 1; i++) { mn = mas_pop_node(&mas); MT_BUG_ON(mt, not_empty(mn)); + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); } MT_BUG_ON(mt, mas_allocated(&mas) != 0); @@ -375,6 +384,7 @@ static noinline void check_new_node(struct maple_tree *mt) mas_node_count(&mas, i); /* Request */ mas_nomem(&mas, GFP_KERNEL); /* Fill request */ mn = mas_pop_node(&mas); /* get the next node. */ + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); mas_destroy(&mas); @@ -382,10 +392,13 @@ static noinline void check_new_node(struct maple_tree *mt) mas_node_count(&mas, i); /* Request */ mas_nomem(&mas, GFP_KERNEL); /* Fill request */ mn = mas_pop_node(&mas); /* get the next node. */ + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); mn = mas_pop_node(&mas); /* get the next node. */ + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); mn = mas_pop_node(&mas); /* get the next node. */ + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); mas_destroy(&mas); } @@ -35369,6 +35382,7 @@ static noinline void check_prealloc(struct maple_tree *mt) MT_BUG_ON(mt, allocated != 1 + height * 3); mn = mas_pop_node(&mas); MT_BUG_ON(mt, mas_allocated(&mas) != allocated - 1); + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); MT_BUG_ON(mt, mas_preallocate(&mas, GFP_KERNEL) != 0); mas_destroy(&mas); @@ -35386,6 +35400,7 @@ static noinline void check_prealloc(struct maple_tree *mt) mas_destroy(&mas); allocated = mas_allocated(&mas); MT_BUG_ON(mt, allocated != 0); + mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); MT_BUG_ON(mt, mas_preallocate(&mas, GFP_KERNEL) != 0); @@ -35756,6 +35771,7 @@ void farmer_tests(void) tree.ma_root = mt_mk_node(node, maple_leaf_64); mt_dump(&tree); + node->parent = ma_parent_ptr(node); ma_free_rcu(node); /* Check things that will make lockdep angry */ -- cgit From 3b7939c8e5345fb84309f2605a4b6f7ac8dd7fce Mon Sep 17 00:00:00 2001 From: Peng Zhang Date: Tue, 11 Apr 2023 12:10:05 +0800 Subject: maple_tree: add a test case to check maple_alloc Add a test case to check whether the number of maple_alloc structures is actually equal to mas->alloc->total. Link: https://lkml.kernel.org/r/20230411041005.26205-2-zhangpeng.00@bytedance.com Signed-off-by: Peng Zhang Cc: Liam R. Howlett Signed-off-by: Andrew Morton --- tools/testing/radix-tree/maple.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'tools/testing/radix-tree/maple.c') diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c index 4c89ff333f6f..9286d3baa12d 100644 --- a/tools/testing/radix-tree/maple.c +++ b/tools/testing/radix-tree/maple.c @@ -55,6 +55,28 @@ struct rcu_reader_struct { struct rcu_test_struct2 *test; }; +static int get_alloc_node_count(struct ma_state *mas) +{ + int count = 1; + struct maple_alloc *node = mas->alloc; + + if (!node || ((unsigned long)node & 0x1)) + return 0; + while (node->node_count) { + count += node->node_count; + node = node->slot[0]; + } + return count; +} + +static void check_mas_alloc_node_count(struct ma_state *mas) +{ + mas_node_count_gfp(mas, MAPLE_ALLOC_SLOTS + 1, GFP_KERNEL); + mas_node_count_gfp(mas, MAPLE_ALLOC_SLOTS + 3, GFP_KERNEL); + MT_BUG_ON(mas->tree, get_alloc_node_count(mas) != mas->alloc->total); + mas_destroy(mas); +} + /* * check_new_node() - Check the creation of new nodes and error path * verification. @@ -69,6 +91,8 @@ static noinline void check_new_node(struct maple_tree *mt) MA_STATE(mas, mt, 0, 0); + check_mas_alloc_node_count(&mas); + /* Try allocating 3 nodes */ mtree_lock(mt); mt_set_non_kernel(0); -- cgit