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From: Jan Kara <jack@suse.cz>
To: Michal Hocko <mhocko@kernel.org>
Cc: Jan Kara <jack@suse.cz>, Dan Williams <dan.j.williams@intel.com>,
	John Hubbard <jhubbard@nvidia.com>,
	Christoph Hellwig <hch@lst.de>, Jason Gunthorpe <jgg@ziepe.ca>,
	John Hubbard <john.hubbard@gmail.com>,
	Matthew Wilcox <willy@infradead.org>,
	Christopher Lameter <cl@linux.com>, Linux MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-rdma <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH 2/2] mm: set PG_dma_pinned on get_user_pages*()
Date: Wed, 27 Jun 2018 14:42:55 +0200	[thread overview]
Message-ID: <20180627124255.np2a6rxy6rb6v7mm@quack2.suse.cz> (raw)
In-Reply-To: <20180627115927.GQ32348@dhcp22.suse.cz>

On Wed 27-06-18 13:59:27, Michal Hocko wrote:
> On Wed 27-06-18 13:53:49, Jan Kara wrote:
> > On Wed 27-06-18 13:32:21, Michal Hocko wrote:
> [...]
> > > Appart from that, do we really care about 32b here? Big DIO, IB users
> > > seem to be 64b only AFAIU.
> > 
> > IMO it is a bad habit to leave unpriviledged-user-triggerable oops in the
> > kernel even for uncommon platforms...
> 
> Absolutely agreed! I didn't mean to keep the blow up for 32b. I just
> wanted to say that we can stay with a simple solution for 32b. I thought
> the g-u-p-longterm has plugged the most obvious breakage already. But
> maybe I just misunderstood.

Most yes, but if you try hard enough, you can still trigger the oops e.g.
with appropriately set up direct IO when racing with writeback / reclaim.

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

  reply	other threads:[~2018-06-27 12:42 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-17  1:25 [PATCH 0/2] mm: gup: don't unmap or drop filesystem buffers john.hubbard
2018-06-17  1:25 ` [PATCH 1/2] consolidate get_user_pages error handling john.hubbard
2018-06-17  1:25 ` [PATCH 2/2] mm: set PG_dma_pinned on get_user_pages*() john.hubbard
2018-06-17 19:53   ` Dan Williams
2018-06-17 20:04     ` Jason Gunthorpe
2018-06-17 20:10       ` Dan Williams
2018-06-17 20:28         ` John Hubbard
2018-06-17 20:28           ` John Hubbard
2018-06-18  8:12           ` Christoph Hellwig
2018-06-18 17:50             ` John Hubbard
2018-06-18 17:50               ` John Hubbard
2018-06-18 17:56               ` Dan Williams
2018-06-18 18:14                 ` John Hubbard
2018-06-18 18:14                   ` John Hubbard
2018-06-18 19:21                   ` Dan Williams
2018-06-18 19:31                     ` Jason Gunthorpe
2018-06-18 20:04                       ` Dan Williams
2018-06-18 21:36                     ` John Hubbard
2018-06-19  8:29                       ` Jan Kara
2018-06-19  9:02                         ` Matthew Wilcox
2018-06-19 10:41                           ` Jan Kara
2018-06-19 18:11                             ` John Hubbard
2018-06-20  1:24                               ` Dan Williams
2018-06-20  1:34                                 ` John Hubbard
2018-06-20  1:57                                   ` Dan Williams
2018-06-20  2:03                                     ` John Hubbard
2018-06-20 12:08                               ` Jan Kara
2018-06-20 22:55                                 ` John Hubbard
2018-06-21 16:30                                   ` Jan Kara
2018-06-25 15:21                                     ` Jan Kara
2018-06-25 19:03                                       ` John Hubbard
2018-06-26  7:52                                         ` Jan Kara
2018-06-26  6:31                                       ` John Hubbard
2018-06-26 11:48                                         ` Jan Kara
2018-06-26 13:47                     ` Michal Hocko
2018-06-26 16:48                       ` Jan Kara
2018-06-27 11:32                         ` Michal Hocko
2018-06-27 11:53                           ` Jan Kara
2018-06-27 11:59                             ` Michal Hocko
2018-06-27 12:42                               ` Jan Kara [this message]
2018-06-27 14:57                                 ` Jason Gunthorpe
2018-06-27 17:02                                   ` Jan Kara
2018-06-28  2:42                                     ` John Hubbard
2018-06-28  9:17                                       ` Jan Kara
2018-07-02  5:52                                         ` Leon Romanovsky
2018-07-02  6:10                                           ` John Hubbard
2018-07-02  6:34                                             ` Leon Romanovsky
2018-07-02  6:41                                               ` John Hubbard
2018-07-02 10:36                                                 ` Michal Hocko
2018-07-02  7:02                                             ` Jan Kara
2018-07-02 14:48                                               ` Michal Hocko
2018-07-02  6:58                                           ` Jan Kara
2018-06-18  8:11         ` Christoph Hellwig
2018-06-19  6:15           ` Leon Romanovsky
2018-06-17 22:19     ` John Hubbard
2018-06-17 22:19       ` John Hubbard
2018-06-18  7:56   ` Christoph Hellwig
2018-06-18 17:44     ` John Hubbard
2018-06-18 17:44       ` John Hubbard
2018-06-17 21:54 ` [PATCH 0/2] mm: gup: don't unmap or drop filesystem buffers Christopher Lameter
2018-06-17 22:23   ` John Hubbard
2018-06-17 22:23     ` John Hubbard
2018-06-18  8:10   ` Christoph Hellwig

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