Re: WARNING in kvmalloc_node

[Jason Wang]

On 2018å02æ14æ 17:28, Daniel Borkmann wrote:
> [ +Jason, +Jesper ]
>
> On 02/14/2018 09:43 AM, Michal Hocko wrote:
> > On Tue 13-02-18 18:55:33, Matthew Wilcox wrote:
> > > On Tue, Feb 13, 2018 at 03:59:01PM -0800, syzbot wrote:
> > [...]
> > > >   kvmalloc include/linux/mm.h:541 [inline]
> > > >   kvmalloc_array include/linux/mm.h:557 [inline]
> > > >   __ptr_ring_init_queue_alloc include/linux/ptr_ring.h:474 [inline]
> > > >   ptr_ring_init include/linux/ptr_ring.h:492 [inline]
> > > >   __cpu_map_entry_alloc kernel/bpf/cpumap.c:359 [inline]
> > > >   cpu_map_update_elem+0x3c3/0x8e0 kernel/bpf/cpumap.c:490
> > > >   map_update_elem kernel/bpf/syscall.c:698 [inline]
> > > Blame the BPF people, not the MM people ;-)
> Heh, not really. ;-)
>
> > Yes. kvmalloc (the vmalloc part) doesn't support GFP_ATOMIC semantic.
> Agree, that doesn't work.
>
> Bug was added in commit 0bf7800f1799 ("ptr_ring: try vmalloc() when kmalloc() fails").
>
> Jason, please take a look at fixing this, thanks!

It looks to me the only solution is to revert that commit.

Will post a patch.

Thanks