Messages in this thread | | | From | Igor Mammedov <> | Subject | Re: udev races with 'arch_register_cpu' to write 1 to /sys/devices/system/cpu/cpu1/online (which is not yet created) | Date | Fri, 10 May 2013 18:34:34 +0200 |
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>On Mon, Apr 30, 2012 at 11:51:49AM -0400, Greg KH wrote: >> On Mon, Apr 30, 2012 at 11:50:18AM -0400, Greg KH wrote: >> > 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. >> >> Oh, I imagine you want to know _how_ to do it too, right? (sorry, I >> couldn't resist...) > >Heh. >> >> Make this a default attribute of the cpu device, and then it will be >> created by the driver core before the uevent is sent to userspace. >> That's what you are supposed to do in the first place, adding files "by >> hand" is wrong, for this very reason. > >OK, will prep up a patch shortly.
Hello Konrad,
Is there a posted/accepted patch or idea was dropped?
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