kvm crash with virtiofs

kvm crash with virtiofs

[Miklos Szeredi]

Hi,

I get the below crash when running virtio-fs on fedora 39.

Note: weirdly this makes chrome running on the host also crash.

Eric Sandeen also reported some bad behavior of virtio-fs on fc39,
which might be related.

Versions:
kernel-6.8.4-200.fc39.x86_64
qemu-kvm-8.1.3-5.fc39.x86_64
virtiofsd-1.10.1-1.fc39.x86_64

Thanks,
Miklos

/usr/libexec/virtiofsd --socket-path=/tmp/vhostqemu --shared-dir /home &

qemu-system-x86_64 -enable-kvm -s -serial none -parallel none -kernel
/home/mszeredi/git/linux/arch/x86_64/boot/bzImage -drive
format=raw,file=/home/mszeredi/root_fs,index=0,if=virtio -drive
format=raw,file=/home/mszeredi/images/ubd1,index=1,if=virtio -chardev
stdio,id=virtiocon0,signal=off -device virtio-serial -device
virtconsole,chardev=virtiocon0 -cpu host -m 16G -smp 8 -object
memory-backend-file,id=mem,size=16G,mem-path=/dev/shm,share=on -numa
node,memdev=mem -net user -net nic,model=virtio-net-pci -fsdev
local,security_model=none,id=fsdev0,path=/home -device virtio-rng-pci
-chardev socket,id=char0,path=/tmp/vhostqemu -device
vhost-user-fs-pci,queue-size=1024,chardev=char0,tag=myfs -device
virtio-9p-pci,fsdev=fsdev0,mount_tag=hostshare -append "root=/dev/vda
console=hvc0 "
[...]
root@kvm:~# time md5sum /host/mszeredi/images/ubd1
error: kvm run failed Bad address
RAX=0000000000000000 RBX=ffff888100044240 RCX=0000000000000000
RDX=ffff888420c59ff0
RSI=0000000000000020 RDI=ffff888420c59ff8 RBP=0000000000000000
RSP=ffffc900016d3898
R8 =ffff888420c59da8 R9 =0000000000000040 R10=0000000000036140
R11=0000000000000005
R12=ffff888420c59ff0 R13=000000000000000d R14=ffffea0010831600
R15=ffff888420c59da8
RIP=ffffffff82168d80 RFL=00010046 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0000 0000000000000000 ffffffff 00c00000
CS =0010 0000000000000000 ffffffff 00a09b00 DPL=0 CS64 [-RA]
SS =0018 0000000000000000 ffffffff 00c09300 DPL=0 DS   [-WA]
DS =0000 0000000000000000 ffffffff 00c00000
FS =0000 00007fb83cea8740 ffffffff 00c00000
GS =0000 ffff88842fd40000 ffffffff 00c00000
LDT=0000 0000000000000000 ffffffff 00c00000
TR =0040 fffffe000012a000 00004087 00008b00 DPL=0 TSS64-busy
GDT=     fffffe0000128000 0000007f
IDT=     fffffe0000000000 00000fff
CR0=80050033 CR2=00007f2d3bd9b0f0 CR3=00000001036ee005 CR4=00770ef0
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000
DR3=0000000000000000
DR6=00000000ffff0ff0 DR7=0000000000000400
EFER=0000000000000d01
Code=90 90 90 90 48 c7 07 00 00 00 00 48 89 fa 48 8d 7f 08 31 c0 <48>
c7 87 30 02 00 00 00 00 00 00 48 89 d1 48 83 e7 f8 48 29 f9 81 c1 40
02 00 00 c1 e9 03

Re: kvm crash with virtiofs

[German Maglione]

On Thu, Jun 6, 2024 at 10:40 AM Miklos Szeredi <mszeredi@redhat.com> wrote:
>
> Hi,
>
> I get the below crash when running virtio-fs on fedora 39.
>
> Note: weirdly this makes chrome running on the host also crash.
>
> Eric Sandeen also reported some bad behavior of virtio-fs on fc39,
> which might be related.
>
> Versions:
> kernel-6.8.4-200.fc39.x86_64
> qemu-kvm-8.1.3-5.fc39.x86_64
> virtiofsd-1.10.1-1.fc39.x86_64
>
> Thanks,
> Miklos
>
> /usr/libexec/virtiofsd --socket-path=/tmp/vhostqemu --shared-dir /home &
>
> qemu-system-x86_64 -enable-kvm -s -serial none -parallel none -kernel
> /home/mszeredi/git/linux/arch/x86_64/boot/bzImage -drive
> format=raw,file=/home/mszeredi/root_fs,index=0,if=virtio -drive
> format=raw,file=/home/mszeredi/images/ubd1,index=1,if=virtio -chardev
> stdio,id=virtiocon0,signal=off -device virtio-serial -device
> virtconsole,chardev=virtiocon0 -cpu host -m 16G -smp 8 -object
> memory-backend-file,id=mem,size=16G,mem-path=/dev/shm,share=on -numa
> node,memdev=mem -net user -net nic,model=virtio-net-pci -fsdev
> local,security_model=none,id=fsdev0,path=/home -device virtio-rng-pci
> -chardev socket,id=char0,path=/tmp/vhostqemu -device
> vhost-user-fs-pci,queue-size=1024,chardev=char0,tag=myfs -device
> virtio-9p-pci,fsdev=fsdev0,mount_tag=hostshare -append "root=/dev/vda
> console=hvc0 "

are you running virtiofsd inside a container?, could you try

-object memory-backend-memfd,id=mem,size=16G,share=on

instead of "-object memory-backend-file..."

> [...]
> root@kvm:~# time md5sum /host/mszeredi/images/ubd1
> error: kvm run failed Bad address
> RAX=0000000000000000 RBX=ffff888100044240 RCX=0000000000000000
> RDX=ffff888420c59ff0
> RSI=0000000000000020 RDI=ffff888420c59ff8 RBP=0000000000000000
> RSP=ffffc900016d3898
> R8 =ffff888420c59da8 R9 =0000000000000040 R10=0000000000036140
> R11=0000000000000005
> R12=ffff888420c59ff0 R13=000000000000000d R14=ffffea0010831600
> R15=ffff888420c59da8
> RIP=ffffffff82168d80 RFL=00010046 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
> ES =0000 0000000000000000 ffffffff 00c00000
> CS =0010 0000000000000000 ffffffff 00a09b00 DPL=0 CS64 [-RA]
> SS =0018 0000000000000000 ffffffff 00c09300 DPL=0 DS   [-WA]
> DS =0000 0000000000000000 ffffffff 00c00000
> FS =0000 00007fb83cea8740 ffffffff 00c00000
> GS =0000 ffff88842fd40000 ffffffff 00c00000
> LDT=0000 0000000000000000 ffffffff 00c00000
> TR =0040 fffffe000012a000 00004087 00008b00 DPL=0 TSS64-busy
> GDT=     fffffe0000128000 0000007f
> IDT=     fffffe0000000000 00000fff
> CR0=80050033 CR2=00007f2d3bd9b0f0 CR3=00000001036ee005 CR4=00770ef0
> DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000
> DR3=0000000000000000
> DR6=00000000ffff0ff0 DR7=0000000000000400
> EFER=0000000000000d01
> Code=90 90 90 90 48 c7 07 00 00 00 00 48 89 fa 48 8d 7f 08 31 c0 <48>
> c7 87 30 02 00 00 00 00 00 00 48 89 d1 48 83 e7 f8 48 29 f9 81 c1 40
> 02 00 00 c1 e9 03
>
>


-- 
German