Messages in this thread | | | From | Liam Howlett <> | Subject | Re: [PATCH] maple_tree: Fix mas_spanning_rebalance() on insufficient data | Date | Fri, 16 Dec 2022 20:47:27 +0000 |
| |
* Andrew Morton <akpm@linux-foundation.org> [221216 14:01]: > On Fri, 16 Dec 2022 18:53:15 +0000 Liam Howlett <liam.howlett@oracle.com> wrote: > > > 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. > > > > 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. > > > > Add a testcase to the maple tree test suite for this issue. > > Shall do. > > > Cc: Andrei Vagin <avagin@gmail.com> > > Cc: usama.anjum@collabora.com > > Reported-by: Mike Rapoport <rppt@kernel.org> > > Fixes: 54a611b60590 ("Maple Tree: add new data structure") > > Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> > > I guess we want a cc:stable there?
Yes, please. I'll be sure to do that in the future for backports.
> > > lib/test_maple_tree.c | 23 +++++++++++++++++++++++ > > Belated review: all this code runs at __init time, so every dang > function in there really should be marked __init, data marked > __initdata, etc. Like lib/test_bitmap.c. > > I wonder if there's some trick we can do external to the .c file to > have the same effect.
This can be built as a module and also runs in userspace via tools/testing/radix-tree. I'm not sure about using __init in this context but I'll look into it.
> > Also, maple_tree_seed():set[] could be static ;). So we don't have to > initialize it at runtime. Better would be static const. Nitpick.
I'll have a look. I'm sure there are more areas within my test code that could be optimised like this.
| |