From: Greg KH <gregkh@linux-foundation.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: zhong jiang <zhongjiang@huawei.com>,
cl@linux.com, penberg@kernel.org, rientjes@google.com,
iamjoonsoo.kim@lge.com, akpm@linux-foundation.org,
mhocko@kernel.org, mgorman@suse.de, vbabka@suse.cz,
andrea@kernel.org, kirill@shutemov.name, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [STABLE PATCH] slub: make ->cpu_partial unsigned int
Date: Sun, 30 Sep 2018 06:10:26 -0700 [thread overview]
Message-ID: <20180930131026.GA25677@kroah.com> (raw)
In-Reply-To: <20180930125038.GA2533@bombadil.infradead.org>
On Sun, Sep 30, 2018 at 05:50:38AM -0700, Matthew Wilcox wrote:
> 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>
>
> Hang on. Christoph acked the _original_ patch going into upstream.
> When he reviewed this patch for _stable_ last week, he asked for more
> investigation. Including this patch in stable is misleading.
But the original patch has been in upstream for a long time now (it went
into 4.17-rc1). If there was a real problem here, whouldn't it have
been resolved already?
And the patch in mainline has Christoph's ack...
thanks,
greg k-h
next prev parent reply other threads:[~2018-09-30 13:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-30 10:28 [STABLE PATCH] slub: make ->cpu_partial unsigned int zhong jiang
2018-09-30 12:37 ` Greg KH
2018-09-30 12:50 ` Matthew Wilcox
2018-09-30 13:10 ` Greg KH [this message]
2018-09-30 13:23 ` Matthew Wilcox
2018-10-02 14:50 ` Christopher Lameter
-- strict thread matches above, loose matches on Subject: below --
2018-09-27 14:43 zhong jiang
2018-09-27 15:26 ` Christopher Lameter
2018-09-27 15:46 ` Greg KH
2018-09-28 8:06 ` zhong jiang
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