From: Catalin Marinas <catalin.marinas@arm.com>
To: Miles Chen <miles.chen@mediatek.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mediatek@lists.infradead.org, wsd_upstream@mediatek.com,
Andrey Konovalov <andreyknvl@google.com>,
Alexander Potapenko <glider@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Dmitry Vyukov <dvyukov@google.com>,
Marco Elver <elver@google.com>, Will Deacon <will@kernel.org>,
"Eric W . Biederman" <ebiederm@xmission.com>,
Song Bao Hua <song.bao.hua@hisilicon.com>,
stable@vger.kernel.org
Subject: Re: [PATCH v2] proc: use untagged_addr() for pagemap_read addresses
Date: Thu, 3 Dec 2020 11:30:21 +0000 [thread overview]
Message-ID: <20201203113020.GE2224@gaia> (raw)
In-Reply-To: <20201127050738.14440-1-miles.chen@mediatek.com>
On Fri, Nov 27, 2020 at 01:07:38PM +0800, Miles Chen wrote:
> Cc: Will Deacon <will.deacon@arm.com>
That should be will@kernel.org.
> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> index 217aa2705d5d..92b277388f05 100644
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -1599,11 +1599,15 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
>
> src = *ppos;
> svpfn = src / PM_ENTRY_BYTES;
> - start_vaddr = svpfn << PAGE_SHIFT;
> end_vaddr = mm->task_size;
>
> /* watch out for wraparound */
> - if (svpfn > mm->task_size >> PAGE_SHIFT)
> + start_vaddr = end_vaddr;
> + if (svpfn < (ULONG_MAX >> PAGE_SHIFT))
Does this need to be strict less-than? I think a less-than or equal
would work better.
> + start_vaddr = untagged_addr(svpfn << PAGE_SHIFT);
> +
> + /* Ensure the address is inside the task */
> + if (start_vaddr > mm->task_size)
> start_vaddr = end_vaddr;
Otherwise the logic looks fine to me. With the above:
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
next prev parent reply other threads:[~2020-12-03 11:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-27 5:07 [PATCH v2] proc: use untagged_addr() for pagemap_read addresses Miles Chen
2020-12-03 11:30 ` Catalin Marinas [this message]
2020-12-04 1:34 ` Miles Chen
2020-12-03 11:45 ` Vincenzo Frascino
2020-12-04 1:33 ` Miles Chen
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