The patch titled Subject: maple_tree: fix mas_empty_area_rev() lower bound validation has been added to the -mm mm-hotfixes-unstable branch. Its filename is maple_tree-fix-mas_empty_area_rev-lower-bound-validation.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 Howlett liam.howlett@oracle.com Subject: maple_tree: fix mas_empty_area_rev() lower bound validation Date: Wed, 11 Jan 2023 20:02:07 +0000
mas_empty_area_rev() was not correctly validating the start of a gap against the lower limit. This could lead to the range starting lower than the requested minimum.
Fix the issue by better validating a gap once one is found.
This commit also adds tests to the maple tree test suite for this issue and tests the mas_empty_area() function for similar bound checking.
Link: https://lkml.kernel.org/r/20230111200136.1851322-1-Liam.Howlett@oracle.com Link: https://bugzilla.kernel.org/show_bug.cgi?id=216911 Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett Liam.Howlett@oracle.com Reported-by: amanieu@gmail.com Link: https://lore.kernel.org/linux-mm/0b9f5425-08d4-8013-aa4c-e620c3b10bb2@leemhu... Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
lib/maple_tree.c | 17 +++---- lib/test_maple_tree.c | 89 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 97 insertions(+), 9 deletions(-)
--- a/lib/maple_tree.c~maple_tree-fix-mas_empty_area_rev-lower-bound-validation +++ a/lib/maple_tree.c @@ -4887,7 +4887,7 @@ static bool mas_rev_awalk(struct ma_stat unsigned long *pivots, *gaps; void __rcu **slots; unsigned long gap = 0; - unsigned long max, min, index; + unsigned long max, min; unsigned char offset;
if (unlikely(mas_is_err(mas))) @@ -4909,8 +4909,7 @@ static bool mas_rev_awalk(struct ma_stat min = mas_safe_min(mas, pivots, --offset);
max = mas_safe_pivot(mas, pivots, offset, type); - index = mas->index; - while (index <= max) { + while (mas->index <= max) { gap = 0; if (gaps) gap = gaps[offset]; @@ -4941,10 +4940,8 @@ static bool mas_rev_awalk(struct ma_stat min = mas_safe_min(mas, pivots, offset); }
- if (unlikely(index > max)) { - mas_set_err(mas, -EBUSY); - return false; - } + if (unlikely((mas->index > max) || (size - 1 > max - mas->index))) + goto no_space;
if (unlikely(ma_is_leaf(type))) { mas->offset = offset; @@ -4961,9 +4958,11 @@ static bool mas_rev_awalk(struct ma_stat return false;
ascend: - if (mte_is_root(mas->node)) - mas_set_err(mas, -EBUSY); + if (!mte_is_root(mas->node)) + return false;
+no_space: + mas_set_err(mas, -EBUSY); return false; }
--- a/lib/test_maple_tree.c~maple_tree-fix-mas_empty_area_rev-lower-bound-validation +++ a/lib/test_maple_tree.c @@ -2517,6 +2517,91 @@ static noinline void check_bnode_min_spa mt_set_non_kernel(0); }
+static noinline void check_empty_area_window(struct maple_tree *mt) +{ + unsigned long i, nr_entries = 20; + MA_STATE(mas, mt, 0, 0); + + for (i = 1; i <= nr_entries; i++) + mtree_store_range(mt, i*10, i*10 + 9, + xa_mk_value(i), GFP_KERNEL); + + /* Create another hole besides the one at 0 */ + mtree_store_range(mt, 160, 169, NULL, GFP_KERNEL); + + /* Check lower bounds that don't fit */ + rcu_read_lock(); + MT_BUG_ON(mt, mas_empty_area_rev(&mas, 5, 90, 10) != -EBUSY); + + mas_reset(&mas); + MT_BUG_ON(mt, mas_empty_area_rev(&mas, 6, 90, 5) != -EBUSY); + + /* Check lower bound that does fit */ + mas_reset(&mas); + MT_BUG_ON(mt, mas_empty_area_rev(&mas, 5, 90, 5) != 0); + MT_BUG_ON(mt, mas.index != 5); + MT_BUG_ON(mt, mas.last != 9); + rcu_read_unlock(); + + /* Check one gap that doesn't fit and one that does */ + rcu_read_lock(); + mas_reset(&mas); + MT_BUG_ON(mt, mas_empty_area_rev(&mas, 5, 217, 9) != 0); + MT_BUG_ON(mt, mas.index != 161); + MT_BUG_ON(mt, mas.last != 169); + + /* Check one gap that does fit above the min */ + mas_reset(&mas); + MT_BUG_ON(mt, mas_empty_area_rev(&mas, 100, 218, 3) != 0); + MT_BUG_ON(mt, mas.index != 216); + MT_BUG_ON(mt, mas.last != 218); + + /* Check size that doesn't fit any gap */ + mas_reset(&mas); + MT_BUG_ON(mt, mas_empty_area_rev(&mas, 100, 218, 16) != -EBUSY); + + /* + * Check size that doesn't fit the lower end of the window but + * does fit the gap + */ + mas_reset(&mas); + MT_BUG_ON(mt, mas_empty_area_rev(&mas, 167, 200, 4) != -EBUSY); + + /* + * Check size that doesn't fit the upper end of the window but + * does fit the gap + */ + mas_reset(&mas); + MT_BUG_ON(mt, mas_empty_area_rev(&mas, 100, 162, 4) != -EBUSY); + + /* Check mas_empty_area forward */ + mas_reset(&mas); + MT_BUG_ON(mt, mas_empty_area(&mas, 0, 100, 9) != 0); + MT_BUG_ON(mt, mas.index != 0); + MT_BUG_ON(mt, mas.last != 8); + + mas_reset(&mas); + MT_BUG_ON(mt, mas_empty_area(&mas, 0, 100, 4) != 0); + MT_BUG_ON(mt, mas.index != 0); + MT_BUG_ON(mt, mas.last != 3); + + mas_reset(&mas); + MT_BUG_ON(mt, mas_empty_area(&mas, 0, 100, 11) != -EBUSY); + + mas_reset(&mas); + MT_BUG_ON(mt, mas_empty_area(&mas, 5, 100, 6) != -EBUSY); + + mas_reset(&mas); + MT_BUG_ON(mt, mas_empty_area(&mas, 0, 8, 10) != -EBUSY); + + mas_reset(&mas); + mas_empty_area(&mas, 100, 165, 3); + + mas_reset(&mas); + MT_BUG_ON(mt, mas_empty_area(&mas, 100, 163, 6) != -EBUSY); + rcu_read_unlock(); +} + static DEFINE_MTREE(tree); static int maple_tree_seed(void) { @@ -2765,6 +2850,10 @@ static int maple_tree_seed(void) check_bnode_min_spanning(&tree); mtree_destroy(&tree);
+ mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE); + check_empty_area_window(&tree); + mtree_destroy(&tree); + #if defined(BENCH) skip: #endif _
Patches currently in -mm which might be from liam.howlett@oracle.com are
nommu-fix-memory-leak-in-do_mmap-error-path.patch nommu-fix-do_munmap-error-path.patch nommu-fix-split_vma-map_count-error.patch maple_tree-fix-mas_empty_area_rev-lower-bound-validation.patch maple_tree-remove-gfp_zero-from-kmem_cache_alloc-and-kmem_cache_alloc_bulk.patch