From: "Michał Mirosław" <emmir@google.com>
To: Andrei Vagin <avagin@gmail.com>
Cc: "Muhammad Usama Anjum" <usama.anjum@collabora.com>,
"Peter Xu" <peterx@redhat.com>,
"David Hildenbrand" <david@redhat.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Danylo Mocherniuk" <mdanylo@google.com>,
"Paul Gofman" <pgofman@codeweavers.com>,
"Cyrill Gorcunov" <gorcunov@gmail.com>,
"Mike Rapoport" <rppt@kernel.org>,
"Nadav Amit" <namit@vmware.com>,
"Alexander Viro" <viro@zeniv.linux.org.uk>,
"Shuah Khan" <shuah@kernel.org>,
"Christian Brauner" <brauner@kernel.org>,
"Yang Shi" <shy828301@gmail.com>,
"Vlastimil Babka" <vbabka@suse.cz>,
"Liam R . Howlett" <Liam.Howlett@oracle.com>,
"Yun Zhou" <yun.zhou@windriver.com>,
"Suren Baghdasaryan" <surenb@google.com>,
"Alex Sierra" <alex.sierra@amd.com>,
"Matthew Wilcox" <willy@infradead.org>,
"Pasha Tatashin" <pasha.tatashin@soleen.com>,
"Axel Rasmussen" <axelrasmussen@google.com>,
"Gustavo A . R . Silva" <gustavoars@kernel.org>,
"Dan Williams" <dan.j.williams@intel.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
"Greg KH" <gregkh@linuxfoundation.org>,
kernel@collabora.com, "Michał Mirosław" <mirq-linux@rere.qmqm.pl>
Subject: Re: [PATCH v26 2/5] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs
Date: Thu, 3 Aug 2023 17:25:13 +0200 [thread overview]
Message-ID: <CABb0KFF7K2SHvSwXMheVAgd3VcJf_twuRsc=P-uTJW9HGQcqfA@mail.gmail.com> (raw)
In-Reply-To: <ZMvDCeUN8qrUmnJV@gmail.com>
On Thu, 3 Aug 2023 at 17:09, Andrei Vagin <avagin@gmail.com> wrote:
> On Thu, Jul 27, 2023 at 02:36:34PM +0500, Muhammad Usama Anjum wrote:
[...]
> > + n_pages = (*end - addr) / PAGE_SIZE;
> > + if (check_add_overflow(p->found_pages, n_pages, &total_pages) ||
> > + total_pages > p->arg.max_pages) {
>
> why do we need to use check_add_overflow here?
>
> > + size_t n_too_much = total_pages - p->arg.max_pages;
>
> it is unsafe to use total_pages if check_add_overflow returns non-zero.
Since we're adding unsigned integers, this is well defined even after overflow.
Best Regards
Michał Mirosław
next prev parent reply other threads:[~2023-08-03 15:25 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-27 9:36 [PATCH v26 0/5] Implement IOCTL to get and optionally clear info about PTEs Muhammad Usama Anjum
2023-07-27 9:36 ` [PATCH v26 1/5] userfaultfd: UFFD_FEATURE_WP_ASYNC Muhammad Usama Anjum
2023-07-27 9:36 ` [PATCH v26 2/5] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs Muhammad Usama Anjum
2023-07-27 11:40 ` Michał Mirosław
2023-07-27 11:48 ` Muhammad Usama Anjum
2023-07-28 11:02 ` WIP: Performance improvements Muhammad Usama Anjum
2023-07-28 11:13 ` Greg KH
2023-08-07 3:32 ` Andrei Vagin
2023-07-27 11:46 ` [PATCH v26 2/5] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs Michał Mirosław
2023-07-27 11:49 ` Muhammad Usama Anjum
2023-08-03 15:08 ` Andrei Vagin
2023-08-03 15:25 ` Michał Mirosław [this message]
2023-08-04 15:59 ` Andrei Vagin
2023-08-04 17:17 ` Michał Mirosław
2023-08-04 6:08 ` Muhammad Usama Anjum
2023-08-04 21:53 ` Andrei Vagin
2023-08-07 4:28 ` Muhammad Usama Anjum
2023-07-27 9:36 ` [PATCH v26 3/5] tools headers UAPI: Update linux/fs.h with the kernel sources Muhammad Usama Anjum
2023-07-27 9:36 ` [PATCH v26 4/5] mm/pagemap: add documentation of PAGEMAP_SCAN IOCTL Muhammad Usama Anjum
2023-07-27 9:36 ` [PATCH v26 5/5] selftests: mm: add pagemap ioctl tests Muhammad Usama Anjum
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