• Thomas Gleixner's avatar
    ia64/sn/hwperf: Replace racy task affinity logic · 9feb42ac
    Thomas Gleixner authored
    sn_hwperf_op_cpu() which is invoked from an ioctl requires to run code on
    the requested cpu. This is achieved by temporarily setting the affinity of
    the calling user space thread to the requested CPU and reset it to the
    original affinity afterwards.
    
    That's racy vs. CPU hotplug and concurrent affinity settings for that
    thread resulting in code executing on the wrong CPU and overwriting the
    new affinity setting.
    
    Replace it by using work_on_cpu_safe() which guarantees to run the code on
    the requested CPU or to fail in case the CPU is offline.
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Cc: Fenghua Yu <fenghua.yu@intel.com>
    Cc: Tony Luck <tony.luck@intel.com>
    Cc: linux-ia64@vger.kernel.org
    Cc: Herbert Xu <herbert@gondor.apana.org.au>
    Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Cc: Sebastian Siewior <bigeasy@linutronix.de>
    Cc: Lai Jiangshan <jiangshanlai@gmail.com>
    Cc: Viresh Kumar <viresh.kumar@linaro.org>
    Cc: Michael Ellerman <mpe@ellerman.id.au>
    Cc: Tejun Heo <tj@kernel.org>
    Cc: "David S. Miller" <davem@davemloft.net>
    Cc: Len Brown <lenb@kernel.org>
    Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1704122251450.2548@nanosSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    9feb42ac
sn_hwperf.c 22.7 KB