linux-kernel - Re: [PATCH net] bpf: cpumap: use GFP_KERNEL instead of GFP_ATOMIC in __cpu_map_entry

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 14 Feb 2018 15:20:20 +0100
From:   Jesper Dangaard Brouer <brouer@...hat.com>
To:     Jason Wang <jasowang@...hat.com>
Cc:     ast@...nel.org, daniel@...earbox.net, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, mst@...hat.com,
        Michal Hocko <mhocko@...nel.org>,
        Matthew Wilcox <willy@...radead.org>,
        akpm@...ux-foundation.org, dhowells@...hat.com, hannes@...xchg.org,
        brouer@...hat.com
Subject: Re: [PATCH net] bpf: cpumap: use GFP_KERNEL instead of GFP_ATOMIC
 in __cpu_map_entry_alloc()

On Wed, 14 Feb 2018 22:17:34 +0800
Jason Wang <jasowang@...hat.com> wrote:

> There're several implications after commit 0bf7800f1799 ("ptr_ring:
> try vmalloc() when kmalloc() fails") with the using of vmalloc() since
> can't allow GFP_ATOMIC but mandate GFP_KERNEL. This will lead a WARN
> since cpumap try to call with GFP_ATOMIC. Fortunately, entry
> allocation of cpumap can only be done through syscall path which means
> GFP_ATOMIC is not necessary, so fixing this by replacing GFP_ATOMIC
> with GFP_KERNEL.
> 
> Reported-by: syzbot+1a240cdb1f4cc88819df@...kaller.appspotmail.com
> Fixes: 0bf7800f1799 ("ptr_ring: try vmalloc() when kmalloc() fails")
> Cc: Michal Hocko <mhocko@...nel.org>
> Cc: Daniel Borkmann <daniel@...earbox.net>
> Cc: Matthew Wilcox <willy@...radead.org>
> Cc: Jesper Dangaard Brouer <brouer@...hat.com>
> Cc: akpm@...ux-foundation.org
> Cc: dhowells@...hat.com
> Cc: hannes@...xchg.org
> Signed-off-by: Jason Wang <jasowang@...hat.com>
> ---
>  kernel/bpf/cpumap.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Acked-by: Jesper Dangaard Brouer <brouer@...hat.com>


> diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
> index fbfdada6..a4bb0b3 100644
> --- a/kernel/bpf/cpumap.c
> +++ b/kernel/bpf/cpumap.c
> @@ -334,7 +334,7 @@ static int cpu_map_kthread_run(void *data)
>  static struct bpf_cpu_map_entry *__cpu_map_entry_alloc(u32 qsize, u32 cpu,
>  						       int map_id)
>  {
> -	gfp_t gfp = GFP_ATOMIC|__GFP_NOWARN;
> +	gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
>  	struct bpf_cpu_map_entry *rcpu;
>  	int numa, err;
>  

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer