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Date:   Sun, 10 Jun 2018 08:58:24 +0200
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Thomas-Mich Richter <tmricht@linux.ibm.com>
Cc:     Mike Galbraith <efault@gmx.de>,
        LKML <linux-kernel@vger.kernel.org>,
        Kees Cook <keescook@chromium.org>
Subject: Re: regression: "95cde3c59966 debugfs: inode: debugfs_create_dir
 uses mode permission from parent" terminally annoys libvirt
Message-ID: <20180610065824.GA17740@kroah.com>
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 <cba2a66b-e8f7-6bf0-d4c1-8f2ba7d89822@linux.ibm.com>
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On Fri, Jun 08, 2018 at 02:13:57PM +0200, Thomas-Mich Richter wrote:
> On 06/08/2018 09:16 AM, Mike Galbraith wrote:
> > Greetings,
> > 
> > $subject bisected and verified via revert.  Box is garden variety
> > i4790, distro is openSUSE Leap 15.0.
> > 
> > Error starting domain: internal error: process exited while connecting to monitor: ioctl(KVM_CREATE_VM) failed: 12 Cannot allocate memory
> > 2018-06-08T03:18:00.453006Z qemu-system-x86_64: failed to initialize KVM: Cannot allocate memory
> > 
> > Traceback (most recent call last):
> >   File "/usr/share/virt-manager/virtManager/asyncjob.py", line 89, in cb_wrapper
> >     callback(asyncjob, *args, **kwargs)
> >   File "/usr/share/virt-manager/virtManager/asyncjob.py", line 125, in tmpcb
> >     callback(*args, **kwargs)
> >   File "/usr/share/virt-manager/virtManager/libvirtobject.py", line 82, in newfn
> >     ret = fn(self, *args, **kwargs)
> >   File "/usr/share/virt-manager/virtManager/domain.py", line 1508, in startup
> >     self._backend.create()
> >   File "/usr/lib64/python3.6/site-packages/libvirt.py", line 1069, in create
> >     if ret == -1: raise libvirtError ('virDomainCreate() failed', dom=self)
> > libvirt.libvirtError: internal error: process exited while connecting to monitor: ioctl(KVM_CREATE_VM) failed: 12 Cannot allocate memory
> > 2018-06-08T03:18:00.453006Z qemu-system-x86_64: failed to initialize KVM: Cannot allocate memory
> > 
> > 95cde3c59966f6371b6bcd9e4e2da2ba64ee9775 is the first bad commit
> > commit 95cde3c59966f6371b6bcd9e4e2da2ba64ee9775
> > Author: Thomas Richter <tmricht@linux.ibm.com>
> > Date:   Fri Apr 27 14:35:47 2018 +0200
> > 
> >     debugfs: inode: debugfs_create_dir uses mode permission from parent
> >     
> ...
> 
> Hi,
> 
> that patch does not allocate any memory, it just sets permission on newly
> created subdirectories in /sys/kernel/debug.
> I do not know what ioctl(KVM_CREATE_VM) does, but maybe requires permissions
> for group and others in that directory.
> 
> Best thing is to revert this patch.

Can you send me the revert so I can queue it up once 4.18-rc1 is out?

thanks,

greg k-h