On Tue, Apr 21, 2015 at 02:55:35PM +0200, Thomas Graf wrote:
> The current code currently only stops inserting rehashes into the
> chain when no resizes are currently scheduled. As long as resizes
> are scheduled and while inserting above the utilization watermark,
> more and more rehashes will be scheduled.
>
> This lead to a perfect DoS storm with thousands of rehashes
> scheduled which lead to thousands of spinlocks to be taken
> sequentially.
>
> Instead, only allow either a series of resizes or a single rehash.
> Drop any further rehashes and return -EBUSY.
>
> Fixes: ccd57b1bd324 ("rhashtable: Add immediate rehash during insertion")
> Signed-off-by: Thomas Graf <[email protected]>
Acked-by: Herbert Xu <[email protected]>
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
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