From: Christoph Hellwig <hch@infradead.org>
To: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>, Jan Kara <jack@suse.cz>,
Jason Gunthorpe <jgg@nvidia.com>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
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Andrew Morton <akpm@linux-foundation.org>,
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Matthew Wilcox <willy@infradead.org>,
Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>,
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Ingo Molnar <mingo@redhat.com>,
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Matthew Rosato <mjrosato@linux.ibm.com>,
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Christian Borntraeger <borntraeger@linux.ibm.com>
Subject: Re: [PATCH v9 0/3] mm/gup: disallow GUP writing to file-backed mappings by default
Date: Wed, 17 May 2023 01:10:17 -0700 [thread overview]
Message-ID: <ZGSL6Q8K5lh4Pdwp@infradead.org> (raw)
In-Reply-To: <503e92f9-fbc2-422b-b0d4-f4cabe3f6802@lucifer.local>
On Wed, May 17, 2023 at 08:55:27AM +0100, Lorenzo Stoakes wrote:
> I'll try to take this in good faith because... yeah. I do get that, I mean
> I literally created a repro for this situation and referenced in the commit
> msg and comments this precise problem in my patch series that
> addresses... this problem :P
>
> Perhaps I'm not being clear but it was simply my intent to highlight that
> yes this is the primary problem but ALSO GUP writing to ostensibly 'clean'
> pages 'behind the back' of a fs is _also_ a problem.
Yes, it absolutely is a problem if that happens. But we can just
fix it in the kernel using the:
lock_page()
copy data
set_page_dirty_locked()
unlock_page();
pattern, and we should have covere every place that did in tree.
But there's no good way to verify it except for regular code audits.
next prev parent reply other threads:[~2023-05-17 8:10 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-04 21:27 [PATCH v9 0/3] mm/gup: disallow GUP writing to file-backed mappings by default Lorenzo Stoakes
2023-05-04 21:27 ` [PATCH v9 1/3] mm/mmap: separate writenotify and dirty tracking logic Lorenzo Stoakes
2023-05-04 21:27 ` [PATCH v9 2/3] mm/gup: disallow FOLL_LONGTERM GUP-nonfast writing to file-backed mappings Lorenzo Stoakes
2023-05-04 21:27 ` [PATCH v9 3/3] mm/gup: disallow FOLL_LONGTERM GUP-fast " Lorenzo Stoakes
2023-05-05 20:21 ` [PATCH v9 0/3] mm/gup: disallow GUP writing to file-backed mappings by default David Hildenbrand
2023-05-05 21:12 ` Lorenzo Stoakes
2023-05-14 19:20 ` Lorenzo Stoakes
2023-05-15 5:14 ` Christoph Hellwig
2023-05-15 11:31 ` Lorenzo Stoakes
2023-05-17 8:26 ` David Hildenbrand
2023-05-15 11:03 ` Kirill A . Shutemov
2023-05-15 11:16 ` Lorenzo Stoakes
2023-05-15 12:12 ` Jason Gunthorpe
2023-05-15 13:07 ` Lorenzo Stoakes
2023-05-17 7:29 ` Jan Kara
2023-05-17 7:40 ` Lorenzo Stoakes
2023-05-17 7:43 ` Christoph Hellwig
2023-05-17 7:55 ` Lorenzo Stoakes
2023-05-17 8:10 ` Christoph Hellwig [this message]
2023-05-17 7:42 ` Christoph Hellwig
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