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From: Andrea Arcangeli <aarcange@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>, Linux-MM <linux-mm@kvack.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Yu Zhao <yuzhao@google.com>, Andy Lutomirski <luto@kernel.org>,
	Peter Xu <peterx@redhat.com>, Pavel Emelyanov <xemul@openvz.org>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Mike Rapoport <rppt@linux.vnet.ibm.com>,
	Minchan Kim <minchan@kernel.org>, Will Deacon <will@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Hugh Dickins <hughd@google.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Matthew Wilcox <willy@infradead.org>,
	Oleg Nesterov <oleg@redhat.com>, Jann Horn <jannh@google.com>,
	Kees Cook <keescook@chromium.org>,
	John Hubbard <jhubbard@nvidia.com>,
	Leon Romanovsky <leonro@nvidia.com>, Jan Kara <jack@suse.cz>,
	Kirill Tkhai <ktkhai@virtuozzo.com>
Subject: Re: [PATCH 0/2] page_count can't be used to decide when wp_page_copy
Date: Thu, 7 Jan 2021 16:54:13 -0500	[thread overview]
Message-ID: <X/eDBbaq7kUvGUyj@redhat.com> (raw)
In-Reply-To: <CAHk-=wjTuS9JB=Ms4WAMaOkGuLmvYwaf2W0JhXxNPdcv4NWZUA@mail.gmail.com>

On Thu, Jan 07, 2021 at 12:32:09PM -0800, Linus Torvalds wrote:
> I think Andrea is blinded by his own love for UFFDIO: when I do a
> debian codesearch for UFFDIO_WRITEPROTECT, all it finds is the kernel
> and strace (and the qemu copies of the kernel headers).

For the record, I feel obliged to reiterate I'm thinking purely in
clear_refs terms here.

It'd be great if we can only focus on clear_refs_write and nothing
else.

Like I said earlier, whatever way clear_refs/softdirty copes with
do_wp_page, uffd-wp can do the identical thing so, uffd-wp is
effectively irrelevant in this whole discussion. Clear-refs/softdirty
predates uffd-wp by several years too.

Thanks,
Andrea



  parent reply	other threads:[~2021-01-07 21:54 UTC|newest]

Thread overview: 98+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-25  9:25 [RFC PATCH v2 0/2] mm: fix races due to deferred TLB flushes Nadav Amit
2020-12-25  9:25 ` [RFC PATCH v2 1/2] mm/userfaultfd: fix memory corruption due to writeprotect Nadav Amit
2021-01-04 12:22   ` Peter Zijlstra
2021-01-04 19:24     ` Andrea Arcangeli
2021-01-04 19:35       ` Nadav Amit
2021-01-04 20:19         ` Andrea Arcangeli
2021-01-04 20:39           ` Nadav Amit
2021-01-04 21:01             ` Andrea Arcangeli
2021-01-04 21:26               ` Nadav Amit
2021-01-05 18:45                 ` Andrea Arcangeli
2021-01-05 19:05                   ` Nadav Amit
2021-01-05 19:45                     ` Andrea Arcangeli
2021-01-05 20:06                       ` Nadav Amit
2021-01-05 21:06                         ` Andrea Arcangeli
2021-01-05 21:43                           ` Peter Xu
2021-01-05  8:13       ` Peter Zijlstra
2021-01-05  8:52         ` Nadav Amit
2021-01-05 14:26           ` Peter Zijlstra
2021-01-05  8:58       ` Peter Zijlstra
2021-01-05  9:22         ` Nadav Amit
2021-01-05 17:58         ` Andrea Arcangeli
2021-01-05 15:08   ` Peter Xu
2021-01-05 18:08     ` Andrea Arcangeli
2021-01-05 18:41       ` Peter Xu
2021-01-05 18:55         ` Andrea Arcangeli
2021-01-05 19:07     ` Nadav Amit
2021-01-05 19:43       ` Peter Xu
2020-12-25  9:25 ` [RFC PATCH v2 2/2] fs/task_mmu: acquire mmap_lock for write on soft-dirty cleanup Nadav Amit
2021-01-05 15:08   ` Will Deacon
2021-01-05 18:20   ` Andrea Arcangeli
2021-01-05 19:26     ` Nadav Amit
2021-01-05 20:39       ` Andrea Arcangeli
2021-01-05 21:20         ` Yu Zhao
2021-01-05 21:22         ` Nadav Amit
2021-01-05 22:16           ` Will Deacon
2021-01-06  0:29             ` Andrea Arcangeli
2021-01-06  0:02           ` Andrea Arcangeli
2021-01-07 20:04           ` [PATCH 0/2] page_count can't be used to decide when wp_page_copy Andrea Arcangeli
2021-01-07 20:04             ` [PATCH 1/2] mm: proc: Invalidate TLB after clearing soft-dirty page state Andrea Arcangeli
2021-01-07 20:04             ` [PATCH 2/2] mm: soft_dirty: userfaultfd: introduce wrprotect_tlb_flush_pending Andrea Arcangeli
2021-01-07 20:17               ` Linus Torvalds
2021-01-07 20:25                 ` Linus Torvalds
2021-01-07 20:58                 ` Andrea Arcangeli
2021-01-07 21:29                   ` Linus Torvalds
2021-01-07 21:53                     ` John Hubbard
2021-01-07 22:00                       ` Linus Torvalds
2021-01-07 22:14                         ` John Hubbard
2021-01-07 22:20                           ` Linus Torvalds
2021-01-07 22:24                             ` Linus Torvalds
2021-01-07 22:37                               ` John Hubbard
2021-01-15 11:27                       ` Jan Kara
2021-01-07 22:31                     ` Andrea Arcangeli
2021-01-07 22:42                       ` Linus Torvalds
2021-01-07 22:51                         ` Linus Torvalds
2021-01-07 23:48                           ` Andrea Arcangeli
2021-01-08  0:25                             ` Linus Torvalds
2021-01-08 12:48                               ` Will Deacon
2021-01-08 16:14                                 ` Andrea Arcangeli
2021-01-08 17:39                                   ` Linus Torvalds
2021-01-08 17:53                                     ` Andrea Arcangeli
2021-01-08 19:25                                       ` Linus Torvalds
2021-01-09  0:12                                         ` Andrea Arcangeli
2021-01-08 17:30                                 ` Linus Torvalds
2021-01-07 23:28                         ` Andrea Arcangeli
2021-01-07 21:36               ` kernel test robot
2021-01-07 21:36                 ` kernel test robot
2021-01-07 20:25             ` [PATCH 0/2] page_count can't be used to decide when wp_page_copy Jason Gunthorpe
2021-01-07 20:32               ` Linus Torvalds
2021-01-07 21:05                 ` Linus Torvalds
2021-01-07 22:02                   ` Andrea Arcangeli
2021-01-07 22:17                     ` Linus Torvalds
2021-01-07 22:56                       ` Andrea Arcangeli
2021-01-09 19:32                   ` Matthew Wilcox
2021-01-09 19:46                     ` Linus Torvalds
2021-01-15 14:30                       ` Jan Kara
2021-01-07 21:54                 ` Andrea Arcangeli [this message]
2021-01-07 21:45               ` Andrea Arcangeli
2021-01-08 13:36                 ` Jason Gunthorpe
2021-01-08 17:00                   ` Andrea Arcangeli
2021-01-08 18:19                     ` Jason Gunthorpe
2021-01-08 18:31                       ` Andy Lutomirski
2021-01-08 18:38                         ` Linus Torvalds
2021-01-08 23:34                         ` Andrea Arcangeli
2021-01-09 19:03                           ` Andy Lutomirski
2021-01-09 19:15                             ` Linus Torvalds
2021-01-08 18:59                       ` Linus Torvalds
2021-01-08 22:43                       ` Andrea Arcangeli
2021-01-09  0:42                         ` Jason Gunthorpe
2021-01-09  2:50                           ` Andrea Arcangeli
2021-01-11 14:30                             ` Jason Gunthorpe
2021-01-13 21:56                           ` Jerome Glisse
2021-01-13 23:39                             ` Jason Gunthorpe
2021-01-14  2:35                               ` Jerome Glisse
2021-01-09  3:49                       ` Hillf Danton
2021-01-11 14:39                         ` Jason Gunthorpe
2021-01-05 21:55         ` [RFC PATCH v2 2/2] fs/task_mmu: acquire mmap_lock for write on soft-dirty cleanup Peter Xu
2021-03-02 22:13 ` [RFC PATCH v2 0/2] mm: fix races due to deferred TLB flushes Peter Xu
2021-03-02 22:14   ` Nadav Amit

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