Re: rhashtable: Use __vmalloc with GFP_ATOMIC for table allocation

David Miller
2015-12-06T03:48:35Z

From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Sat, 5 Dec 2015 15:03:54 +0800

> Sorry Dave but you'll have to revert this because I've been able
> to trigger the following crash with the patch:
>
> Testing concurrent rhashtable access from 50 threads
> ------------[ cut here ]------------
> kernel BUG at ../mm/vmalloc.c:1337!
> invalid opcode: 0000 [#1] PREEMPT SMP
>
> The reason is that because I was testing insertions with BH disabled,
> and __vmalloc doesn't like that, even with GFP_ATOMIC. As we
> obviously want to continue to support rhashtable users inserting
> entries with BH disabled, we'll have to look for an alternate
> solution.

Ok, reverted, thanks for the heads up.