The quilt patch titled
Subject: maple_tree: remove rcu_read_lock() from mt_validate()
has been removed from the -mm tree. Its filename was
maple_tree-remove-rcu_read_lock-from-mt_validate.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Subject: maple_tree: remove rcu_read_lock() from mt_validate()
Date: Tue, 20 Aug 2024 13:54:17 -0400
The write lock should be held when validating the tree to avoid updates
racing with checks. Holding the rcu read lock during a large tree
validation may also cause a prolonged rcu read window and "rcu_preempt
detected stalls" warnings.
Link: https://lore.kernel.org/all/0000000000001d12d4062005aea1@xxxxxxxxxx/
Link: https://lkml.kernel.org/r/20240820175417.2782532-1-Liam.Howlett@xxxxxxxxxx
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reported-by: syzbot+036af2f0c7338a33b0cd@xxxxxxxxxxxxxxxxxxxxxxxxx
Cc: Hillf Danton <hdanton@xxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/maple_tree.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
--- a/lib/maple_tree.c~maple_tree-remove-rcu_read_lock-from-mt_validate
+++ a/lib/maple_tree.c
@@ -7566,14 +7566,14 @@ static void mt_validate_nulls(struct map
* 2. The gap is correctly set in the parents
*/
void mt_validate(struct maple_tree *mt)
+ __must_hold(mas->tree->ma_lock)
{
unsigned char end;
MA_STATE(mas, mt, 0, 0);
- rcu_read_lock();
mas_start(&mas);
if (!mas_is_active(&mas))
- goto done;
+ return;
while (!mte_is_leaf(mas.node))
mas_descend(&mas);
@@ -7594,9 +7594,6 @@ void mt_validate(struct maple_tree *mt)
mas_dfs_postorder(&mas, ULONG_MAX);
}
mt_validate_nulls(mt);
-done:
- rcu_read_unlock();
-
}
EXPORT_SYMBOL_GPL(mt_validate);
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
mm-vma-correctly-position-vma_iterator-in-__split_vma.patch
mm-vma-introduce-abort_munmap_vmas.patch
mm-vma-introduce-vmi_complete_munmap_vmas.patch
mm-vma-extract-the-gathering-of-vmas-from-do_vmi_align_munmap.patch
mm-vma-introduce-vma_munmap_struct-for-use-in-munmap-operations.patch
mm-vma-change-munmap-to-use-vma_munmap_struct-for-accounting-and-surrounding-vmas.patch
mm-vma-extract-validate_mm-from-vma_complete.patch
mm-vma-inline-munmap-operation-in-mmap_region.patch
mm-vma-expand-mmap_region-munmap-call.patch
mm-vma-support-vma-==-null-in-init_vma_munmap.patch
mm-mmap-reposition-vma-iterator-in-mmap_region.patch
mm-vma-track-start-and-end-for-munmap-in-vma_munmap_struct.patch
mm-clean-up-unmap_region-argument-list.patch
mm-mmap-avoid-zeroing-vma-tree-in-mmap_region.patch
mm-change-failure-of-map_fixed-to-restoring-the-gap-on-failure.patch
mm-mmap-use-phys_pfn-in-mmap_region.patch
mm-mmap-use-vms-accounted-pages-in-mmap_region.patch
ipc-shm-mm-drop-do_vma_munmap.patch
mm-move-may_expand_vm-check-in-mmap_region.patch
mm-vma-drop-incorrect-comment-from-vms_gather_munmap_vmas.patch
mm-vmah-optimise-vma_munmap_struct.patch
