From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id 75F9E6B0003 for ; Wed, 14 Feb 2018 06:51:24 -0500 (EST) Received: by mail-wr0-f198.google.com with SMTP id t6so7259785wrc.12 for ; Wed, 14 Feb 2018 03:51:24 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id p18si6715592wmb.159.2018.02.14.03.51.23 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 14 Feb 2018 03:51:23 -0800 (PST) Date: Wed, 14 Feb 2018 12:51:19 +0100 From: Michal Hocko Subject: Re: WARNING in kvmalloc_node Message-ID: <20180214115119.GA3443@dhcp22.suse.cz> References: <001a1144c4ca5dc9d6056520c7b7@google.com> <20180214025533.GA28811@bombadil.infradead.org> <20180214084308.GX3443@dhcp22.suse.cz> <24351362-a099-3317-2b96-8cdc6835eb1e@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <24351362-a099-3317-2b96-8cdc6835eb1e@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Jason Wang Cc: Daniel Borkmann , Matthew Wilcox , syzbot , akpm@linux-foundation.org, dhowells@redhat.com, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mingo@kernel.org, rppt@linux.vnet.ibm.com, syzkaller-bugs@googlegroups.com, vbabka@suse.cz, viro@zeniv.linux.org.uk, Alexei Starovoitov , netdev@vger.kernel.org, brouer@redhat.com, "Michael S. Tsirkin" On Wed 14-02-18 19:47:30, Jason Wang wrote: > > > On 2018a1'02ae??14ae?JPY 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. Do you really need this to be GFP_ATOMIC? I can see some callers are under RCU read lock but can we perhaps do the allocation outside of this section? -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org