From: Igor Mammedov <imammedo@redhat.com>
To: Raphael Norwitz <raphael.norwitz@nutanix.com>
Cc: qemu-devel@nongnu.org
Subject: Re: Qemu master crashing on boot when using file backend for memory
Date: Wed, 25 Mar 2020 10:46:44 +0100 [thread overview]
Message-ID: <20200325104644.5ea8d0a6@office.mammed.net> (raw)
In-Reply-To: <20200325024924.GA1518@localhost.localdomain>
On Tue, 24 Mar 2020 22:50:46 -0400
Raphael Norwitz <raphael.norwitz@nutanix.com> wrote:
> On Thu, Mar 12, 2020 at 11:54:50AM +0100, Igor Mammedov wrote:
> >
> > On Thu, 12 Mar 2020 01:36:48 -0400
> > Raphael Norwitz <raphael.norwitz@nutanix.com> wrote:
> >
> > > When I try run master qemu I am hitting a divide by zero error. It seems
> > > to be coming from util/oslib-posix.c in touch_all_pages(). see line 477:
> > >
> > > numpages_per_thread = numpages / memset_num_threads;
> > >
> > > Poking around the crash dumps, I can see that the smp_cpus parameter
> > > passed in to touch_all_pages() is 0. Going up the stack to
> > > host_memory_backend_memory_complete() I see backend->prealloc_threads is
> > > also 0.
> > >
> > > Here’s how I am running qemu
> > >
> > > ./x86_64-softmmu/qemu-system-x86_64 \
> > > -kernel /boot/vmlinuz-3.10.0-1062.el7.x86_64 \
> > > -netdev user,id=net0,hostfwd=tcp::2250-:22 \
> > > -device e1000e,netdev=net0 \
> > > -m 1G \
> > > -initrd /boot/initramfs-3.10.0-1062.el7.x86_64.img \
> > > -object memory-backend-file,id=ram-node0,prealloc=yes,mem-path=mem,share=yes,size=1G \
> > > -numa node,nodeid=0,cpus=0,memdev=ram-node0
> > >
> > > I don't see this error on a slightly older qemu, as of commit 105b07f1
> > > (January 27th).
> > >
> > > Interestingly when I remove the memory-backend-file parameter I don’t
> > > see the error, i.e. this works:
> > >
> > > ./x86_64-softmmu/qemu-system-x86_64 \
> > > -kernel /boot/vmlinuz-3.10.0-1062.el7.x86_64 \
> > > -netdev user,id=net0,hostfwd=tcp::2250-:22 \
> > > -device e1000e,netdev=net0 \
> > > -m 1G \
> > > -initrd /boot/initramfs-3.10.0-1062.el7.x86_64.img
> > >
> > > Looking at the blame data for backends/hostmem.c I see commit ffac16fa
> > > introduced some churn in this part of the code. Has anyone else seen
> > > this issue? Could I be doing something wrong here?
> >
> > It's know issue, see
> > "[PATCH] oslib-posix: initialize mutex and condition variable
> > for a fix
> > >
> >
>
> I'm testing on qemu master now. Looks like this patch has been merged
> and I'm still seeing the same crash.
Thanks for report, fix is on the way to qemu-devel
prev parent reply other threads:[~2020-03-25 9:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-12 5:36 Qemu master crashing on boot when using file backend for memory Raphael Norwitz
2020-03-12 10:54 ` Igor Mammedov
2020-03-25 2:50 ` Raphael Norwitz
2020-03-25 9:46 ` Igor Mammedov [this message]
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