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[Xen-devel] [BUG] race condition in blkfront (probably other frontends too).


  • To: Xen Development Mailing List <xen-devel@xxxxxxxxxxxxxxxxxxx>
  • From: Gerd Hoffmann <kraxel@xxxxxxxxxx>
  • Date: Thu, 24 Jul 2008 16:15:07 +0200
  • Delivery-date: Thu, 24 Jul 2008 07:16:30 -0700
  • List-id: Xen developer discussion <xen-devel.lists.xensource.com>

  Hi folks,

I've just seen it with the block frontend, but most likely the other
frontend drivers are affected too.  The blkfront drivers goes into
initialized state (in blkfront_probe), and *after* that xenbus_dev_probe
sets a watch on the state node of the device.  That leaves a race window
open for the backend going into connected state before the watch is
active.  If that happens the frontend doesn't notice the backend is
ready and never ever goes into connected state ...

cheers,
  Gerd

-- 
http://kraxel.fedorapeople.org/xenner/

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