Re: [LKP] [writeback] 8bc4ad9498: INFO: suspicious RCU usage. ]

[Fengguang Wu]

Hi Jens and Tejun,

> The command line was in the original email:
>
> $ qemu-system-x86_64 -enable-kvm -cpu Westmere -m 512M
>
> And agree, in general it'd be nice if there was a link to the image as
> well, so that folks can reproduce.

Yes we have a reproduce script internally, however need to polish it
up and make it general usable by kernel developers.

CC Philip. It'd be helpful to give more priority to the "lkp qemu"
reproduce command.

For the warning here, it does not depend on any initrd, I just
confirmed this simple script can reproduce the problem.

-----------------------------------------------------------------------------
#!/bin/bash

kernel=$1

kvm=(
       qemu-system-x86_64
       -enable-kvm
       -cpu Westmere
       -kernel $kernel
       -m 1024
       -smp 1
       -device e1000,netdev=net0
       -netdev user,id=net0
       -boot order=nc
       -no-reboot
       -watchdog i6300esb
       -watchdog-action debug
       -rtc base=localtime
       -nographic
)


append=(
       ip=::::vm-kbuild-yocto-ia32-17::dhcp
       root=/dev/ram0
       debug
       apic=debug
       sysrq_always_enabled
       rcupdate.rcu_cpu_stall_timeout=100
       net.ifnames=0
       printk.devkmsg=on
       panic=-1
       softlockup_panic=1
       nmi_watchdog=panic
       oops=panic
       load_ramdisk=2
       prompt_ramdisk=0
       systemd.log_level=err
       ignore_loglevel
       earlyprintk=ttyS0,115200
       console=ttyS0,115200
       console=tty0
       vga=normal
       rw
)

"${kvm[@]}" -append "${append[*]}"
-----------------------------------------------------------------------------

Thanks,
Fengguang