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From: Andrew Morton <akpm@linux-foundation.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: stable@vger.kernel.org, "Christoph Hellwig" <hch@lst.de>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Logan Gunthorpe" <logang@deltatee.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/5] mm, devm_memremap_pages: handle errors allocating final devres action
Date: Mon, 21 May 2018 16:10:26 -0700	[thread overview]
Message-ID: <20180521161026.709d5f2876e44f151da3d179@linux-foundation.org> (raw)
In-Reply-To: <152694212460.5484.13180030631810166467.stgit@dwillia2-desk3.amr.corp.intel.com>

On Mon, 21 May 2018 15:35:24 -0700 Dan Williams <dan.j.williams@intel.com> wrote:

> The last step before devm_memremap_pages() returns success is to
> allocate a release action to tear the entire setup down. However, the
> result from devm_add_action() is not checked.
> 
> Checking the error also means that we need to handle the fact that the
> percpu_ref may not be killed by the time devm_memremap_pages_release()
> runs. Add a new state flag for this case.
> 
> Cc: <stable@vger.kernel.org>
> Fixes: e8d513483300 ("memremap: change devm_memremap_pages interface...")
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: "Jérôme Glisse" <jglisse@redhat.com>
> Cc: Logan Gunthorpe <logang@deltatee.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Why the cc:stable?  The changelog doesn't describe the end-user-visible
impact of the bug (it always should, for this reason).

AFAICT we only go wrong when a small GFP_KERNEL allocation fails
(basically never happens), with undescribed results :(

  reply	other threads:[~2018-05-21 23:10 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-21 22:35 [PATCH 0/5] mm: rework hmm to use devm_memremap_pages Dan Williams
2018-05-21 22:35 ` [PATCH 1/5] mm, devm_memremap_pages: mark devm_memremap_pages() EXPORT_SYMBOL_GPL Dan Williams
2018-05-22  6:29   ` Christoph Hellwig
2018-05-21 22:35 ` [PATCH 2/5] mm, devm_memremap_pages: handle errors allocating final devres action Dan Williams
2018-05-21 23:10   ` Andrew Morton [this message]
2018-05-22  0:07     ` Dan Williams
2018-05-22 16:42       ` Logan Gunthorpe
2018-05-22 16:56         ` Dan Williams
2018-05-22 17:03           ` Logan Gunthorpe
2018-05-22 17:25             ` Dan Williams
2018-05-22 17:36               ` Logan Gunthorpe
2018-05-22  6:30   ` Christoph Hellwig
2018-05-21 22:35 ` [PATCH 3/5] mm, hmm: use devm semantics for hmm_devmem_{add, remove} Dan Williams
2018-05-22  6:30   ` Christoph Hellwig
2018-05-21 22:35 ` [PATCH 4/5] mm, hmm: replace hmm_devmem_pages_create() with devm_memremap_pages() Dan Williams
2018-05-22  6:31   ` Christoph Hellwig
2018-05-22 17:13   ` Logan Gunthorpe
2018-05-22 21:38     ` Dan Williams
2018-05-21 22:35 ` [PATCH 5/5] mm, hmm: mark hmm_devmem_{add, add_resource} EXPORT_SYMBOL_GPL Dan Williams
2018-05-22  6:32   ` Christoph Hellwig
2018-05-22 21:31     ` Andrew Morton
2018-06-05 18:24       ` Jerome Glisse
2018-05-24  0:10 ` [PATCH 0/5] mm: rework hmm to use devm_memremap_pages Jerome Glisse
2018-05-24  3:18   ` Dan Williams
2018-05-24  6:35     ` Christoph Hellwig
2018-05-29 22:22     ` Dave Airlie
2018-05-29 22:31       ` Dan Williams
2018-05-29 23:00         ` Dave Airlie
2018-05-29 23:33           ` Dan Williams
2018-06-05 18:48             ` Jerome Glisse
2018-06-05 22:19               ` Dave Airlie
2018-06-05 23:06                 ` Dan Williams
2018-06-06  0:08                   ` Jerome Glisse
2018-06-06  1:33                     ` Dan Williams
2018-06-06  7:14                       ` Christoph Hellwig
2018-06-07 14:16                       ` Jerome Glisse
2018-06-07 18:39                         ` Dan Williams

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