linux-kernel - Re: [PATCH v24 2/5] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CANaxB-zvYpKw-aeF8nd_spARdkV29H7ZJDDhusnmqOPZX1xXtw@mail.gmail.com>
Date:   Tue, 11 Jul 2023 12:42:44 -0700
From:   Andrei Vagin <avagin@...il.com>
To:     Muhammad Usama Anjum <usama.anjum@...labora.com>
Cc:     Peter Xu <peterx@...hat.com>, David Hildenbrand <david@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michał Mirosław <emmir@...gle.com>,
        Danylo Mocherniuk <mdanylo@...gle.com>,
        Paul Gofman <pgofman@...eweavers.com>,
        Cyrill Gorcunov <gorcunov@...il.com>,
        Mike Rapoport <rppt@...nel.org>, Nadav Amit <namit@...are.com>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Shuah Khan <shuah@...nel.org>,
        Christian Brauner <brauner@...nel.org>,
        Yang Shi <shy828301@...il.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        "Liam R . Howlett" <Liam.Howlett@...cle.com>,
        Yun Zhou <yun.zhou@...driver.com>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Alex Sierra <alex.sierra@....com>,
        Matthew Wilcox <willy@...radead.org>,
        Pasha Tatashin <pasha.tatashin@...een.com>,
        Axel Rasmussen <axelrasmussen@...gle.com>,
        "Gustavo A . R . Silva" <gustavoars@...nel.org>,
        Dan Williams <dan.j.williams@...el.com>,
        linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-mm@...ck.org, linux-kselftest@...r.kernel.org,
        Greg KH <gregkh@...uxfoundation.org>, kernel@...labora.com
Subject: Re: [PATCH v24 2/5] fs/proc/task_mmu: Implement IOCTL to get and
 optionally clear info about PTEs

On Tue, Jul 11, 2023 at 5:53 AM Muhammad Usama Anjum
<usama.anjum@...labora.com> wrote:

<snip>

> +static int pagemap_scan_pte_hole(unsigned long addr, unsigned long end,
> +                                int depth, struct mm_walk *walk)
> +{
> +       unsigned long n_pages = (end - addr)/PAGE_SIZE;
> +       struct pagemap_scan_private *p = walk->private;
> +       struct vm_area_struct *vma = walk->vma;
> +       int ret = 0;
> +
> +       if (!vma)
> +               return 0;
> +
> +       if (IS_PM_SCAN_GET(p->flags)) {
> +               if (n_pages > p->max_pages - p->found_pages)
> +                       n_pages = p->max_pages - p->found_pages;
> +
> +               ret = pagemap_scan_output(PM_SCAN_FLAGS(false, false, false,
> +                                         false, false), p, addr, n_pages);

Why do we report holes unconditionally?

> +       }
> +
> +       if (IS_PM_SCAN_WP(p->flags) &&
> +           uffd_wp_range(vma, addr, end - addr, true) < 0)
> +               ret = -EINVAL;
> +
> +       return ret;
> +}

Thanks,
Andrei