RE: [PATCH net 0/3] Fix for BPF devmap percpu allocation splat

From: David Laight
Date: Tue Oct 17 2017 - 11:03:14 EST


From: Daniel Borkmann
> Sent: 17 October 2017 15:56
>
> The set fixes a splat in devmap percpu allocation when we alloc
> the flush bitmap. Patch 1 is a prerequisite for the fix in patch 2,
> patch 1 is rather small, so if this could be routed via -net, for
> example, with Tejun's Ack that would be good. Patch 3 gets rid of
> remaining PCPU_MIN_UNIT_SIZE checks, which are percpu allocator
> internals and should not be used.

Does it make sense to allow the user program to try to allocate ever
smaller very large maps until it finds one that succeeds - thus
using up all the percpu space?

Or is this a 'root only' 'shoot self in foot' job?

David