Re: timer_bh behaviour incorrect for 2.2.13?

Helge Hafting (helge.hafting@idb.hist.no)
Fri, 10 Dec 1999 09:33:40 +0100


>you have missed the _real_ reason why the above 'bug' was there. It's a
>feature and prevents denial of service attacks. Especially wrt. networking
>it's very easy to flood a box with bh traffic, and if we are not careful
>then slower systems (routers) can effectively be locked up just by
>bombarding them with small/tricky packets. So we were always intentionally
>trying to guarantee that bhs do not get rerun infinitely.

A DOS attack may come via the network, but probably not from the timer
interrupt. So how about making that one a special case, so the timer
bottom half always runs when necassary, while the others can be delayed
for DOS protection?

Helge Hafting

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