Re: Notifier chains are unsafe

[Keith Owens]

On Tue, 1 Nov 2005 16:20:43 -0500 (EST), 
Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
>You mean the RCU-style update?  It will hang when a callout routine tries 
>to deregister itself as it is running, although we could add a new 
>unregister_self API to handle that.  Just check for num_callers equal to 1 
>instead of 0.

A callout on an atomic notifer chain has no business calling the
register/unregister functions.  It makes no sense for an atomic context
to call a routine that can sleep or block.

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