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SubjectRe: [STABLE PATCH] slub: make ->cpu_partial unsigned int
On Sun, Sep 30, 2018 at 06:28:21PM +0800, zhong jiang wrote:
> From: Alexey Dobriyan <adobriyan@gmail.com>
>
> [ Upstream commit e5d9998f3e09359b372a037a6ac55ba235d95d57 ]
>
> /*
> * cpu_partial determined the maximum number of objects
> * kept in the per cpu partial lists of a processor.
> */
>
> Can't be negative.
>
> I hit a real issue that it will result in a large number of memory leak.
> Becuase Freeing slabs are in interrupt context. So it can trigger this issue.
> put_cpu_partial can be interrupted more than once.
> due to a union struct of lru and pobjects in struct page, when other core handles
> page->lru list, for eaxmple, remove_partial in freeing slab code flow, It will
> result in pobjects being a negative value(0xdead0000). Therefore, a large number
> of slabs will be added to per_cpu partial list.
>
> I had posted the issue to community before. The detailed issue description is as follows.
>
> https://www.spinics.net/lists/kernel/msg2870979.html
>
> After applying the patch, The issue is fixed. So the patch is a effective bugfix.
> It should go into stable.
>
> Link: http://lkml.kernel.org/r/20180305200730.15812-15-adobriyan@gmail.com
> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> Acked-by: Christoph Lameter <cl@linux.com>
> Cc: Pekka Enberg <penberg@kernel.org>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Cc: <stable@vger.kernel.org> # 4.4.x

This didn't apply to 4.14.y and any reason you didn't cc: the stable
mailing list for the other stable developers to see it?

I've fixed up the patch, but next time please always cc: the stable
list.

thanks,

greg k-h

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