Re: PROBLEM: NULL pointer dereference in kernel 4.14.6

[Randy Dunlap]

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)ÂÂÂ = 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, <unfinished ...>) = ?
>>> +++ killed by SIGKILL +++
>>> [1]ÂÂÂ 12078 killedÂÂÂÂ 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