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[209.132.183.28]) by mx.google.com with ESMTPS id g1si29263885qki.181.2019.07.25.00.45.45 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 25 Jul 2019 00:45:45 -0700 (PDT) Received-SPF: pass (google.com: domain of jasowang@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of jasowang@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=jasowang@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 356623084246; Thu, 25 Jul 2019 07:45:44 +0000 (UTC) Received: from [10.72.12.18] (ovpn-12-18.pek2.redhat.com [10.72.12.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2591B5C6D2; Thu, 25 Jul 2019 07:45:16 +0000 (UTC) Subject: Re: WARNING in __mmdrop To: "Michael S. Tsirkin" , Jason Gunthorpe Cc: syzbot , aarcange@redhat.com, akpm@linux-foundation.org, christian@brauner.io, davem@davemloft.net, ebiederm@xmission.com, elena.reshetova@intel.com, guro@fb.com, hch@infradead.org, james.bottomley@hansenpartnership.com, jglisse@redhat.com, keescook@chromium.org, ldv@altlinux.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-parisc@vger.kernel.org, luto@amacapital.net, mhocko@suse.com, mingo@kernel.org, namit@vmware.com, peterz@infradead.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk, wad@chromium.org References: <0000000000008dd6bb058e006938@google.com> <000000000000964b0d058e1a0483@google.com> <20190721044615-mutt-send-email-mst@kernel.org> <20190722141152.GA13711@ziepe.ca> <20190725015402-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: <6389178e-35f2-28a1-4d36-3696bcde6af0@redhat.com> Date: Thu, 25 Jul 2019 15:44:54 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190725015402-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Thu, 25 Jul 2019 07:45:44 +0000 (UTC) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2019/7/25 下午2:02, Michael S. Tsirkin wrote: > On Mon, Jul 22, 2019 at 11:11:52AM -0300, Jason Gunthorpe wrote: >> On Sun, Jul 21, 2019 at 06:02:52AM -0400, Michael S. Tsirkin wrote: >>> On Sat, Jul 20, 2019 at 03:08:00AM -0700, syzbot wrote: >>>> syzbot has bisected this bug to: >>>> >>>> commit 7f466032dc9e5a61217f22ea34b2df932786bbfc >>>> Author: Jason Wang >>>> Date: Fri May 24 08:12:18 2019 +0000 >>>> >>>> vhost: access vq metadata through kernel virtual address >>>> >>>> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=149a8a20600000 >>>> start commit: 6d21a41b Add linux-next specific files for 20190718 >>>> git tree: linux-next >>>> final crash: https://syzkaller.appspot.com/x/report.txt?x=169a8a20600000 >>>> console output: https://syzkaller.appspot.com/x/log.txt?x=129a8a20600000 >>>> kernel config: https://syzkaller.appspot.com/x/.config?x=3430a151e1452331 >>>> dashboard link: https://syzkaller.appspot.com/bug?extid=e58112d71f77113ddb7b >>>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10139e68600000 >>>> >>>> Reported-by: syzbot+e58112d71f77113ddb7b@syzkaller.appspotmail.com >>>> Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual >>>> address") >>>> >>>> For information about bisection process see: https://goo.gl/tpsmEJ#bisection >>> >>> OK I poked at this for a bit, I see several things that >>> we need to fix, though I'm not yet sure it's the reason for >>> the failures: >> This stuff looks quite similar to the hmm_mirror use model and other >> places in the kernel. I'm still hoping we can share this code a bit more. > Right. I think hmm is something we should look at. Exactly. I plan to do that. Thanks