From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: gregkh@linuxfoundation.org, linux-kernel@vger.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).
Date: Mon, 30 Apr 2012 11:37:23 -0400 [thread overview]
Message-ID: <20120430153723.GB23485@phenom.dumpdata.com> (raw)
In-Reply-To: <20120430153623.GA23485@phenom.dumpdata.com>
On Mon, Apr 30, 2012 at 11:36:23AM -0400, Konrad Rzeszutek Wilk wrote:
> Hey Greg,
Grr.. Incorrectly added LKML to it. Sorry about that.
>
> 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?
>
next parent reply other threads:[~2012-04-30 15:43 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20120430153623.GA23485@phenom.dumpdata.com>
2012-04-30 15:37 ` Konrad Rzeszutek Wilk [this message]
2012-04-30 15:50 ` udev races with 'arch_register_cpu' to write 1 to /sys/devices/system/cpu/cpu1/online (which is not yet created) Greg KH
2012-04-30 15:51 ` Greg KH
2012-04-30 16:17 ` Konrad Rzeszutek Wilk
2013-05-10 16:34 ` Igor Mammedov
2013-05-13 13:31 ` Konrad Rzeszutek Wilk
2013-05-13 14:25 ` Greg KH
2013-05-13 22:05 ` [RFC 0/2] cpu: fix leak and udev race in register_cpu() Igor Mammedov
2013-05-14 13:19 ` Konrad Rzeszutek Wilk
2013-05-14 14:45 ` Greg KH
2013-05-13 22:05 ` [PATCH 1/2] cpu: fix "crash_notes" leak " Igor Mammedov
2013-05-14 13:16 ` Konrad Rzeszutek Wilk
2013-05-13 22:05 ` [PATCH 2/2] cpu: make sure that cpu/online file created before KOBJ_ADD is emitted Igor Mammedov
2013-05-14 13:17 ` Konrad Rzeszutek Wilk
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