svn commit: r263755 - head/sys/kern

[David Xu]

On 2014/03/27 16:37, Mateusz Guzik wrote:
> On Thu, Mar 27, 2014 at 03:45:17PM +0800, David Xu wrote:
>> I think the async process pointer can be cleared when a process exits
>> by registering an event handler. please see attached patch.
>>
>
> Sure, but I'm not very fond of this solution.
>
> This is a rather obscure bug you wont hit unless you explicitly try,
> and even then you need root privs by default.
>
OK, but I don't like the bug exists in kernel. It is not obscure for me,
I can run "shutdown now" command, and insert a device, and then the
kernel will write garbage data into freed memory space.

> As such writing a callback function which will be executed for all exiting
> processes seems unjustified for me.
>
> Ideally we would get some mechanism which would allow to register
> callbacks for events related to given entity. Then it could be used to
> provide a "call this function when process p exits", amongst other things.
>

Yes, but the callback itself is cheap enough and is not worth to be
per-entity entry.