* Wei Yang <richard.weiyang@xxxxxxxxx> [250211 03:11]: > On Mon, Feb 10, 2025 at 09:31:28AM -0500, Liam R. Howlett wrote: > >* Wei Yang <richard.weiyang@xxxxxxxxx> [250207 20:26]: > > > >The subject of this patch set makes the issue sound much more sever than > >it is. It currently sounds like a memory leak or a UAF, which isn't the > >case. > > > > Not intend to exaggerate the impact. > > Is this one would be better? > > maple_tree: make sure each node is dead on destroy Not really, you are fixing two nodes, one isn't even to do with the destry/dead node. You are also not making sure each node is dead, but fixing an issue with the leaf node. maple_tree: Fix the replacement of a root leaf node ? > > >The root node may remain usable for the duration of the rcu window if > >it's a leaf node. The impact is pretty minor - you may see the old data > >on calls that happen in the same rcu window - which is the case anyways. > > > >You should also say maple_tree: in the subject since this is > >going to linux-mm. Not a really big deal since each patch in the series > >specifies the maple tree. > > > > Thanks, will add it in next version. > > >> Per my understanding, on destroy we should set each node dead. But current > >> code miss this when the maple tree has only the root node. > >> > >> The reason is mt_destroy_walk() leverage mte_destroy_descend() to set > >> node dead, but this is skipped since the only root node is a leaf. > >> > >> Patch 1 fixes this. > >> > >> When adding a test case, I found we always get the new value even we leave the > >> old root node not dead. It turns out we always re-walk the tree in mas_walk(). > >> It looks like a typo on the status check of mas_walk(). > >> > >> Patch 2 fixes this. > >> > >> Patch 3 add a test case to assert retrieving new value when overwriting the > >> whole range to a tree with only root node > >> > >> Wei Yang (3): > >> maple_tree: may miss to set node dead on destroy > >> maple_tree: restart walk on correct status > >> maple_tree: assert retrieving new value on a tree with only root node > >> > >> lib/maple_tree.c | 4 +++- > >> tools/testing/radix-tree/maple.c | 24 ++++++++++++++++++++++++ > >> 2 files changed, 27 insertions(+), 1 deletion(-) > >> > >> -- > >> 2.34.1 > >> > > -- > Wei Yang > Help you, Help me
