From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>,
Yumei Huang <yuhuang@redhat.com>, KVM <kvm@vger.kernel.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux ACPI <linux-acpi@vger.kernel.org>,
Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: DAX can not work on virtual nvdimm device
Date: Fri, 19 Aug 2016 12:30:47 -0600 [thread overview]
Message-ID: <20160819183047.GA7216@linux.intel.com> (raw)
In-Reply-To: <CAPcyv4hVgi6Hw8Beg=Nt78+U0QNJN9mBGWEp3V6bg86NaM3Q6Q@mail.gmail.com>
On Fri, Aug 19, 2016 at 07:59:29AM -0700, Dan Williams wrote:
> On Fri, Aug 19, 2016 at 4:19 AM, Xiao Guangrong
> <guangrong.xiao@linux.intel.com> wrote:
> >
> > Hi Dan,
> >
> > Recently, Redhat reported that nvml test suite failed on QEMU/KVM,
> > more detailed info please refer to:
> > https://bugzilla.redhat.com/show_bug.cgi?id=1365721
> >
> > The reason for this bug is that the memory region created by mmap()
> > on the dax-based file was gone so that the region can not be found
> > in /proc/self/smaps during the runtime.
> >
> > This is a simple way to trigger this issue:
> > mount -o dax /dev/pmem0 /mnt/pmem/
> > vim /mnt/pmem/xxx
> > then 'vim' is crashed due to segment fault.
> >
> > This bug can be reproduced on your tree, the top commit is
> > 10d7902fa0e82b (dax: unmap/truncate on device shutdown), the kernel
> > configure file is attached.
> >
> > Your thought or comment is highly appreciated.
>
> I'm going to be offline until Tuesday, but I will investigate when I'm
> back. In the meantime if Ross or Vishal had an opportunity to take a
> look I wouldn't say "no" :).
I haven't been able to reproduce this vim segfault. I'm using QEMU v2.6.0,
and the kernel commit you mentioned, and your kernel config.
Here's my QEMU command line:
sudo ~/qemu/bin/qemu-system-x86_64 /var/lib/libvirt/images/alara.qcow2 \
-machine pc,nvdimm -m 8G,maxmem=100G,slots=100 -object \
memory-backend-file,id=mem1,share,mem-path=/dev/pmem0,size=8G -device \
nvdimm,memdev=mem1,id=nv1 -smp 6 -machine pc,accel=kvm
With this I'm able to mkfs the guest's /dev/pmem0, mount it with -o dax, and
write a file with vim.
Can you reproduce your results with a pmem device created via a memmap kernel
command line parameter in the guest? You'll need to update your kernel
config to enable CONFIG_X86_PMEM_LEGACY and CONFIG_X86_PMEM_LEGACY_DEVICE.
next prev parent reply other threads:[~2016-08-19 18:30 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-19 11:19 DAX can not work on virtual nvdimm device Xiao Guangrong
2016-08-19 14:59 ` Dan Williams
2016-08-19 18:30 ` Ross Zwisler [this message]
2016-08-21 9:55 ` Boaz Harrosh
2016-08-29 7:54 ` Xiao Guangrong
2016-08-29 19:30 ` Ross Zwisler
2016-08-30 6:53 ` Xiao Guangrong
2016-08-30 17:09 ` Dan Williams
2016-08-31 8:44 ` Xiao Guangrong
2016-08-31 16:46 ` Ross Zwisler
2016-09-02 2:57 ` Ross Zwisler
2016-09-06 15:06 ` Jan Kara
2016-09-08 20:47 ` Ross Zwisler
2016-09-09 9:19 ` Jan Kara
2016-09-09 14:03 ` Theodore Ts'o
2016-09-09 16:34 ` Ross Zwisler
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