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Date: Mon, 30 Apr 2012 11:50:18 -0400 From: Greg KH <gregkh@...uxfoundation.org> To: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com> Cc: linux-kernel@...r.kernel.org Subject: Re: udev races with 'arch_register_cpu' to write 1 to /sys/devices/system/cpu/cpu1/online (which is not yet created). On Mon, Apr 30, 2012 at 11:36:23AM -0400, Konrad Rzeszutek Wilk wrote: > Hey Greg, > > Hoping you can help with some guidance on how to fix this. > > The issue is with CPU hotplug is that when a CPU goes up > it calls 'arch_register_cpu' which eventually calls > register_cpu. That function does these two things: > > 251 error = device_register(&cpu->dev); > 252 if (!error && cpu->hotpluggable) > 253 register_cpu_control(cpu); > > and the device_register creates a nice little SysFS directory: > > /sys/devices/system/cpu/cpu2/ which at line 251 has the 'add' attribute > but no 'online' attribute. udev then tries to echo 1 to the 'online' > and it we get: > udevd-work[2421]: error opening ATTR{/sys/devices/system/cpu/cpu2/online} for writing: No such file or directory > > Line 253 creates said 'online' and at that time udev [or the system admin] > can write 1 to 'online' and the CPU goes up. > > So .. any thoughts? Is there some way to inhibit from uevent being sent > until line 253 has run? Yes. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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