* Qemu master crashing on boot when using file backend for memory
@ 2020-03-12 5:36 Raphael Norwitz
2020-03-12 10:54 ` Igor Mammedov
0 siblings, 1 reply; 4+ messages in thread
From: Raphael Norwitz @ 2020-03-12 5:36 UTC (permalink / raw)
To: qemu-devel
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?
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Qemu master crashing on boot when using file backend for memory
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
0 siblings, 1 reply; 4+ messages in thread
From: Igor Mammedov @ 2020-03-12 10:54 UTC (permalink / raw)
To: Raphael Norwitz; +Cc: qemu-devel
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
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Qemu master crashing on boot when using file backend for memory
2020-03-12 10:54 ` Igor Mammedov
@ 2020-03-25 2:50 ` Raphael Norwitz
2020-03-25 9:46 ` Igor Mammedov
0 siblings, 1 reply; 4+ messages in thread
From: Raphael Norwitz @ 2020-03-25 2:50 UTC (permalink / raw)
To: Igor Mammedov; +Cc: qemu-devel
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.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Qemu master crashing on boot when using file backend for memory
2020-03-25 2:50 ` Raphael Norwitz
@ 2020-03-25 9:46 ` Igor Mammedov
0 siblings, 0 replies; 4+ messages in thread
From: Igor Mammedov @ 2020-03-25 9:46 UTC (permalink / raw)
To: Raphael Norwitz; +Cc: qemu-devel
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
^ permalink raw reply [flat|nested] 4+ messages in thread
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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
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