Re: [LKP] [writeback] 8bc4ad9498: INFO: suspicious RCU usage. ]
From: Ye Xiaolong
Date: Wed Sep 07 2016 - 22:07:44 EST
On 09/08, Fengguang Wu wrote:
>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.
Yes, just confirmed that v4.8-rc5 doesn't have this warning, while kernel
for the updated commit (fa0e2cb1af765691fabd329f03cad563a0eebf18) on branch
wb-buf-throttle could reproduce it.
Thanks,
Xiaolong
>
>-----------------------------------------------------------------------------
>#!/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