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@xxxxxxxxxxxxxxx> 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. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
