This is a note to let you know that I've just added the patch titled
maple_tree: fix mas_spanning_rebalance() on insufficient data
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
maple_tree-fix-mas_spanning_rebalance-on-insufficient-data.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0abb964aae3da746ea2fd4301599a6fa26da58db Mon Sep 17 00:00:00 2001
From: Liam Howlett <liam.howlett@xxxxxxxxxx>
Date: Mon, 19 Dec 2022 16:20:15 +0000
Subject: maple_tree: fix mas_spanning_rebalance() on insufficient data
From: Liam Howlett <liam.howlett@xxxxxxxxxx>
commit 0abb964aae3da746ea2fd4301599a6fa26da58db upstream.
Mike Rapoport contacted me off-list with a regression in running criu.
Periodic tests fail with an RCU stall during execution. Although rare, it
is possible to hit this with other uses so this patch should be backported
to fix the regression.
This patchset adds the fix and a test case to the maple tree test
suite.
This patch (of 2):
An insufficient node was causing an out-of-bounds access on the node in
mas_leaf_max_gap(). The cause was the faulty detection of the new node
being a root node when overwriting many entries at the end of the tree.
Fix the detection of a new root and ensure there is sufficient data prior
to entering the spanning rebalance loop.
Link: https://lkml.kernel.org/r/20221219161922.2708732-1-Liam.Howlett@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20221219161922.2708732-2-Liam.Howlett@xxxxxxxxxx
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reported-by: Mike Rapoport <rppt@xxxxxxxxxx>
Tested-by: Mike Rapoport <rppt@xxxxxxxxxx>
Cc: Andrei Vagin <avagin@xxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxx>
Cc: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
lib/maple_tree.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -2989,7 +2989,9 @@ static int mas_spanning_rebalance(struct
mast->free = &free;
mast->destroy = &destroy;
l_mas.node = r_mas.node = m_mas.node = MAS_NONE;
- if (!(mast->orig_l->min && mast->orig_r->max == ULONG_MAX) &&
+
+ /* Check if this is not root and has sufficient data. */
+ if (((mast->orig_l->min != 0) || (mast->orig_r->max != ULONG_MAX)) &&
unlikely(mast->bn->b_end <= mt_min_slots[mast->bn->type]))
mast_spanning_rebalance(mast);
Patches currently in stable-queue which might be from liam.howlett@xxxxxxxxxx are
queue-6.1/test_maple_tree-add-test-for-mas_spanning_rebalance-on-insufficient-data.patch
queue-6.1/maple_tree-fix-mas_spanning_rebalance-on-insufficient-data.patch
