Re: [BUG] 2.4.x RT signal leak with kupdated (and maybe others)

[Nigel Cunningham]

Hi.

For what it's worth, Software Suspend sends signals to daemons, but it
uses flush_signals() to ensure they don't have any other effect than
getting the process stopped during the cycle.

Nigel

On Wed, 2003-10-01 at 21:24, Benjamin Herrenschmidt wrote:
> > That's because nobody else sends signals to the daemons I guess. And
> > even if they do the daemon won't clear the pending bitflag, so there's
> > no risk to queue more than 1 non-RT entry per signal per daemon like it
> > happened with kupdate.
> 
> And any daemon can cause the same leak by sending it RT signals... I just
> verified sending for example a bunch of 33's (SIGRTMIN) to khubd, that
> increased the count permanently.
> 
> I agree this should not happen normally, and I suppose only root can do
> that and we aren't here to prevent root from shooting itself in the
> foot, are we ?
> 
> The question is should I spend some time adding some flush_signals() to
> the loop of those various kernel daemons I can find or that isn't worth ?
> 
> Regarding kupated, dequeue_signal is a better option as we actually care
> about the signal, I'm testing a patch it will be there in a few minutes.
> 
> Ben.
>  
> 
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-- 
Nigel Cunningham
495 St Georges Road South, Hastings 4201, New Zealand

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	-- Romans 5:6, NIV.

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