Re: [Qemu-devel] [PATCH] hw/i386: fix nvdimm check error path

[Stefan Hajnoczi]

On Fri, Jun 16, 2017 at 05:03:48PM +0300, Michael S. Tsirkin wrote:
> On Fri, Jun 16, 2017 at 02:19:56PM +0100, Stefan Hajnoczi wrote:
> > On Fri, Jun 09, 2017 at 04:16:15PM +0100, Stefan Hajnoczi wrote:
> > > Commit e987c37aee1752177906847630d32477da57e705 ("hw/i386: check if
> > > nvdimm is enabled before plugging") introduced a check to reject nvdimm
> > > hotplug if -machine pc,nvdimm=on was not given.
> > > 
> > > This check executes after pc_dimm_memory_plug() has already completed
> > > and does not reverse the effect of this function in the case of failure.
> > > 
> > > Perform the check before calling pc_dimm_memory_plug().  This fixes the
> > > following abort:
> > > 
> > >   $ qemu -M accel=kvm -m 1G,slots=4,maxmem=8G \
> > >          -object 
> > > memory-backend-file,id=mem1,share=on,mem-path=nvdimm.dat,size=1G
> > >   (qemu) device_add nvdimm,memdev=mem1
> > >   nvdimm is not enabled: missing 'nvdimm' in '-M'
> > >   (qemu) device_add nvdimm,memdev=mem1
> > >   Core dumped
> > > 
> > > The backtrace is:
> > > 
> > >   #0  0x00007fffdb5b191f in raise () at /lib64/libc.so.6
> > >   #1  0x00007fffdb5b351a in abort () at /lib64/libc.so.6
> > >   #2  0x00007fffdb5a9da7 in __assert_fail_base () at /lib64/libc.so.6
> > >   #3  0x00007fffdb5a9e52 in  () at /lib64/libc.so.6
> > >   #4  0x000055555577a5fa in qemu_ram_set_idstr (new_block=0x555556747a00, 
> > > name=<optimized out>, address@hidden) at qemu/exec.c:1709
> > >   #5  0x0000555555a0fe86 in vmstate_register_ram (address@hidden, 
> > > address@hidden) at migration/savevm.c:2293
> > >   #6  0x0000555555965088 in pc_dimm_memory_plug (address@hidden, 
> > > address@hidden, address@hidden, align=<optimized out>, address@hidden)
> > >       at hw/mem/pc-dimm.c:110
> > >   #7  0x000055555581d89b in pc_dimm_plug (errp=0x7fffffffc6c0, 
> > > dev=0x555556705590, hotplug_dev=<optimized out>) at qemu/hw/i386/pc.c:1713
> > >   #8  0x000055555581d89b in pc_machine_device_plug_cb 
> > > (hotplug_dev=<optimized out>, dev=0x555556705590, errp=0x7fffffffc6c0) at 
> > > qemu/hw/i386/pc.c:2004
> > >   #9  0x0000555555914da6 in device_set_realized (obj=<optimized out>, 
> > > value=<optimized out>, errp=0x7fffffffc7e8) at hw/core/qdev.c:926
> > > 
> > > Cc: Haozhong Zhang <address@hidden>
> > > Signed-off-by: Stefan Hajnoczi <address@hidden>
> > > ---
> > >  hw/i386/pc.c | 14 ++++++++------
> > >  1 file changed, 8 insertions(+), 6 deletions(-)
> > 
> > Michael: Do you want to take this through your tree?
> 
> Yes - it will be in the next pull.

Thank you!

Stefan

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