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    SubjectRE: [PATCH] Fix the race between smp_call_function and CPU booting
    Date
    In fact, I started two scripts running:
    1/ One script:
    echo 0 > /sys/devices/system/cpuX/online
    echo 1 > /sys/devices/system/cpuX/online
    Rerunning the above commands in loop

    2/Another script:
    echo 1 > /debug/smp_call_test
    usleep 50000
    Rerunning the above command in loop

    This race issue can be easy to be reproduced in several minutes;
    For simplify your test as mine(just two CPUs), you can set other non-booting CPUs as offline
    at first and just leave one non-booting CPU.

    > -----Original Message-----
    > From: Peter Zijlstra [mailto:peterz@infradead.org]
    > Sent: Friday, March 23, 2012 6:26 PM
    > To: Liu, Chuansheng
    > Cc: linux-kernel@vger.kernel.org; Yanmin Zhang; tglx@linutronix.de; Srivatsa S.
    > Bhat
    > Subject: RE: [PATCH] Fix the race between smp_call_function and CPU booting
    >
    > On Thu, 2012-03-22 at 00:59 +0000, Liu, Chuansheng wrote:
    > > Below is the complete test patch. Just run the simpl_loop_onoffline.sh
    > > and simpl_loop_smpcalling.sh concurrently to reproduce the race.
    > >
    > What I did was:
    >
    > for i in {2..23} ; do echo 0 > /sys/devices/system/cpu/cpu${i}/online ; done while
    > usleep 50000 ; do echo 1 > /debug/smp_call_test ; done & while :; do echo $i >
    > /sys/devices/system/cpu/cpu1/online ; let i^=1 ; done
    >
    > and this has been running for well over 30 minutes.. is there anything else one
    > needs to do?
    >



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