On Thu, Jul 29, 2021 at 08:57:54PM +0800, Miaohe Lin wrote: > rtpn might be NULL in very rare case. We have better to check it before > dereferencing it. Since memcg can live with NULL rb_tree_per_node in > soft_limit_tree, warn this case and continue. > > Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx> > --- > mm/memcontrol.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 5b4592d1e0f2..70a32174e7c4 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -7109,6 +7109,8 @@ static int __init mem_cgroup_init(void) > rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, > node_online(node) ? node : NUMA_NO_NODE); > > + if (WARN_ON_ONCE(!rtpn)) > + continue; I also really doubt that it makes any sense to continue in this case. If this allocations fails (at the very beginning of the system's life, it's an __init function), something is terribly wrong and panic'ing on a NULL-pointer dereference sounds like a perfect choice. Is this a real world problem? Do I miss something?
