Messages in this thread | | | Date | Tue, 17 Jan 2006 16:52:17 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 4/9] uml: fix spinlock recursion and sleep-inside-spinlock in error path |
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"Paolo 'Blaisorblade' Giarrusso" <blaisorblade@yahoo.it> wrote: > > > From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> > > In this error path, when the interface has had a problem, we call dev_close(), > which is disallowed for two reasons: > > *) takes again the UML internal spinlock, inside the ->stop method of this > device > *) can be called in process context only, while we're in interrupt context. > > I've also thought that calling dev_close() may be a wrong policy to follow, but > it's not up to me to decide that. > > However, we may end up with multiple dev_close() queued on the same device. > But the initial test for (dev->flags & IFF_UP) makes this harmless, though - > and dev_close() is supposed to care about races with itself. So there's no harm > in delaying the shutdown, IMHO. > > Something to mark the interface as "going to shutdown" would be appreciated, but > dev_deactivate has the same problems as dev_close(), so we can't use it either. > > ... > + /* dev_close can't be called in interrupt context, and takes > + * again lp->lock. > + * And dev_close() can be safely called multiple times on the > + * same device, since it tests for (dev->flags & IFF_UP). So > + * there's no harm in delaying the device shutdown. */ > + schedule_work(&close_work); > goto out; > }
This callback can be pending for an arbitrary amount of time. I'd have expected to see a flush_sceduled_work() somewhere in the driver to force all such pending work to complete before we destroy things which that callback wil be using. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.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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