Re: [Bugme-new] [Bug 33502] New: Caught 64-bit read from uninitialized memory in __alloc_skb

Eric Dumazet
2011-05-10T20:06:33Z

Le mardi 10 mai 2011 à 14:38 -0500, Christoph Lameter a écrit :

> Optimizing? You think about this as concurrency issue between multiple
> cpus. That is fundamentally wrong. This is dealing with access to per cpu
> data and the concurrency issues are only with code running on the *same*
> cpu.
>

If you enable irqs, then this object can be allocated by _this_ cpu and
given to another one.

Another cpu can free the page, forcing you to call a very expensive
function, that might give obsolete result as soon it returns.

Maybe I am just tired tonight, this seems very obvious, I must miss
something.