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Re: Qemu master crashing on boot when using file backend for memory
From: |
Raphael Norwitz |
Subject: |
Re: Qemu master crashing on boot when using file backend for memory |
Date: |
Tue, 24 Mar 2020 22:50:46 -0400 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Thu, Mar 12, 2020 at 11:54:50AM +0100, Igor Mammedov wrote:
>
> On Thu, 12 Mar 2020 01:36:48 -0400
> Raphael Norwitz <address@hidden> 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.