Re: regression: insmod module failed in VM with nvdimm on

[Marc Zyngier]

On Wed, 30 Nov 2022 02:52:35 +0000,
"chenxiang (M)" <chenxiang66@hisilicon.com> wrote:
> 
> Hi,
> 
> We boot the VM using following commands (with nvdimm on)  (qemu
> version 6.1.50, kernel 6.0-r4):

How relevant is the presence of the nvdimm? Do you observe the failure
without this?

> 
> qemu-system-aarch64 -machine
> virt,kernel_irqchip=on,gic-version=3,nvdimm=on  -kernel
> /home/kernel/Image -initrd /home/mini-rootfs/rootfs.cpio.gz -bios
> /root/QEMU_EFI.FD -cpu host -enable-kvm -net none -nographic -m
> 2G,maxmem=64G,slots=3 -smp 4 -append 'rdinit=init console=ttyAMA0
> ealycon=pl0ll,0x90000000 pcie_ports=native pciehp.pciehp_debug=1'
> -object memory-backend-ram,id=ram1,size=10G -device
> nvdimm,id=dimm1,memdev=ram1  -device ioh3420,id=root_port1,chassis=1
> -device vfio-pci,host=7d:01.0,id=net0,bus=root_port1
> 
> Then in VM we insmod a module, vmalloc error occurs as follows (kernel
> 5.19-rc4 is normal, and the issue is still on kernel 6.1-rc4):
> 
> estuary:/$ insmod /lib/modules/$(uname -r)/hnae3.ko
> [    8.186563] vmap allocation for size 20480 failed: use
> vmalloc=<size> to increase size

Have you tried increasing the vmalloc size to check that this is
indeed the problem?

[...]

> We git bisect the code, and find the patch c5a89f75d2a ("arm64: kaslr:
> defer initialization to initcall where permitted").

I guess you mean commit fc5a89f75d2a instead, right?

> Do you have any idea about the issue?

I sort of suspect that the nvdimm gets vmap-ed and consumes a large
portion of the vmalloc space, but you give very little information
that could help here...

        M.

-- 
Without deviation from the norm, progress is not possible.