[PATCH] maple_tree: exchange entry1/entry2 to make seen_entry2 do see new value
Liam R. Howlett
Liam.Howlett at oracle.com
Mon Apr 7 19:32:51 PDT 2025
* Wei Yang <richard.weiyang at gmail.com> [250407 22:10]:
> During run_check_rcu() and run_check_rcu_slowread(), we would write
> entry2/entry3 to specified range and eval_rcu_entry() would test whether
> these value is seen by reader.
>
> So we have three entries in struct rcu_test_struct:
>
> * entry1: the original value during tree initialization
> * entry2/entry3: value to be written
>
> Currently we set entry2 to the original value, this would fool
> eval_rcu_entry() to see entry2 even there is no writer.
>
> Exchange entry1/entry2 to make seen_entry2 do see new value.
>
> Signed-off-by: Wei Yang <richard.weiyang at gmail.com>
> CC: Liam R. Howlett <Liam.Howlett at Oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett at Oracle.com>
> ---
> tools/testing/radix-tree/maple.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c
> index 1e293e4d856d..fc6578f81cb0 100644
> --- a/tools/testing/radix-tree/maple.c
> +++ b/tools/testing/radix-tree/maple.c
> @@ -35323,8 +35323,8 @@ static noinline void __init check_rcu_threaded(struct maple_tree *mt)
> vals.mt = mt;
> vals.index = 4390;
> vals.last = 4398;
> - vals.entry1 = xa_mk_value(4390);
> - vals.entry2 = xa_mk_value(439);
> + vals.entry1 = xa_mk_value(439);
> + vals.entry2 = xa_mk_value(4390);
> vals.entry3 = xa_mk_value(439);
> vals.seen_entry2 = 0;
> vals.range_start = 4316;
> @@ -35360,8 +35360,8 @@ static noinline void __init check_rcu_threaded(struct maple_tree *mt)
> vals.mt = mt;
> vals.index = 4390;
> vals.last = 4398;
> - vals.entry1 = xa_mk_value(4390);
> - vals.entry2 = xa_mk_value(439);
> + vals.entry1 = xa_mk_value(439);
> + vals.entry2 = xa_mk_value(4390);
> vals.entry3 = xa_mk_value(4391);
> vals.seen_toggle = 0;
> vals.seen_added = 0;
> --
> 2.34.1
>
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