On Thu, Dec 02, 2021 at 05:23:42PM +0200, Leon Romanovsky wrote: > The problem is that this WARN_ON() is triggered by the users. ... or the problem is that you don't do a sanity check between the user and the MM system. I mean, that's what this conversation is about -- is it a bug to be asking for this much memory in the first place? > At least in the RDMA world, users can provide huge sizes and they expect > to get plain -ENOMEM and not dump stack, because it happens indirectly > to them. > > In our case, these two kvcalloc() generates WARN_ON(). > > umem_odp->pfn_list = kvcalloc( > npfns, sizeof(*umem_odp->pfn_list), GFP_KERNEL); Does it really make sense for the user to specify 2^31 PFNs in a single call? I mean, that's 8TB of memory. Should RDMA put its own limit in here, or should it rely on kvmalloc returning -ENOMEM?
