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Date: Thu, 8 Sep 2016 09:43:13 +0800
From: Fengguang Wu <fengguang.wu@intel.com>
To: Jens Axboe <axboe@fb.com>
Cc: Tejun Heo <tj@kernel.org>, kernel test robot <xiaolong.ye@intel.com>,
        lkp@01.org, Philip Li <philip.li@intel.com>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [LKP] [writeback] 8bc4ad9498: INFO: suspicious RCU usage. ]
Message-ID: <20160908014313.fdebw6ig2m6edy46@wfg-t540p.sh.intel.com>
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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