From mboxrd@z Thu Jan 1 00:00:00 1970 From: Randy Dunlap Subject: Re: PROBLEM: NULL pointer dereference in kernel 4.14.6 Date: Sun, 17 Dec 2017 10:31:39 -0800 Message-ID: References: <1513512885.3653140.1207725096.395A9CCC@webmail.messagingengine.com> <08995310-d853-ee77-ed1f-26cc336a4a30@incorrekt.com> <54a16e07-70e6-adda-ebdb-06349b4f8e86@infradead.org> <04a4e27d-e291-66c3-ab88-e1343c6955f2@incorrekt.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=emiAojK1n3zVB1/AYpEfx7PypQ9U1Vj3ilpcz7pVYdM=; b=f8OmFo8qhJK48e/1ag4qwwapAs SAfCuMkyZzfYBZxontUlGTQAgc5CXMVF9iwmGElAmgWVBTEd2ycN3dLLDMFaD6O7dCfVlUWVVQokT PeHlq2kCsG29ptaznvO3b9KsI2xciFmeja/kdU0cai6KOh/EWyR994AcU/YUfUcMEzW/LfWOyIJsO uAjJhRkw6tZm6AvF+MXyRp1mVNNl+lx1AgZGHI+LXREk68AJFHAFfsmQFlgWOU/l2oj0yqdl2ICHD K/hZD5pQZ93AM7t7nEjFj+R/XquevBJ2a4YpgjxikL0VHb7jG3mT+F7psFkOngimvjP4oq46RU3O0 In-Reply-To: <04a4e27d-e291-66c3-ab88-e1343c6955f2-CgwIDsGnGWjby3iVrkZq2A@public.gmane.org> Content-Language: en-US Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="utf-8" To: Bronek Kozicki , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On 12/17/2017 10:30 AM, Bronek Kozicki wrote: > On 17/12/2017 18:25, Randy Dunlap wrote: >> On 12/17/2017 09:49 AM, Bronek Kozicki wrote: >>> I just upgraded to 4.14.7 and tried to reproduce this error, this time under strace. As you can see this happens when systemctl tries to read a specific entry under /sys/fs . In case this matters, the entry is for a small virtual machine running under qemu/kvm and managed by libvirt. >>> >>> open("/sys/fs/cgroup/unified/machine.slice", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 5 >>> fstat(5, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0 >>> getdents(5, /* 12 entries */, 32768)    = 464 >>> openat(AT_FDCWD, "/sys/fs/cgroup/unified/machine.slice/machine-qemu\\x2d1\\x2dkartuzy\\x2dspice.scope/cgroup.procs", O_RDONLY|O_CLOEXEC) = 8 >>> fstat(8, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0 >>> read(8,  )              = ? >>> +++ killed by SIGKILL +++ >>> [1]    12078 killed     strace -- systemctl status >>> >>> >>> B. >>> >> >> Hi, >> >> Can you reproduce this without using (loading) the XFS modules? >> They cause the kernel to be tainted. > > I think you mean ZFS - I cannot do that. It is my root filesystem. Sorry, yes, I did mean ZFS. thanks, -- ~Randy