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From: Luis Chamberlain <mcgrof@kernel.org>
To: Liang Wang <wangliang101@huawei.com>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: palmerdabbelt@google.com, linux-kernel@vger.kernel.org,
	gregkh@linuxfoundation.org, linux@armlinux.org.uk,
	linux-arm-kernel@lists.infradead.org, stable@vger.kernel.org,
	wangle6@huawei.com, kepler.chenxin@huawei.com,
	nixiaoming@huawei.com, wangkefeng.wang@huawei.com
Subject: Re: [PATCH v3] lib: Use PFN_PHYS() in devmem_is_allowed()
Date: Mon, 2 Aug 2021 15:40:02 -0700	[thread overview]
Message-ID: <YQh0Quhry/+dbTbn@bombadil.infradead.org> (raw)
In-Reply-To: <20210731025057.78825-1-wangliang101@huawei.com>

On Sat, Jul 31, 2021 at 10:50:57AM +0800, Liang Wang wrote:
> The physical address may exceed 32 bits on 32-bit systems with
> more than 32 bits of physcial address,use PFN_PHYS() in devmem_is_allowed(),
> or the physical address may overflow and be truncated.
> We found this bug when mapping a high addresses through devmem tool,
> when CONFIG_STRICT_DEVMEM is enabled on the ARM with ARM_LPAE and devmem
> is used to map a high address that is not in the iomem address range,
> an unexpected error indicating no permission is returned.
> 
> This bug was initially introduced from v2.6.37, and the function was moved
> to lib when v5.11.
> 
> Cc: Luis Chamberlain <mcgrof@kernel.org>
> Fixes: 087aaffcdf9c ("ARM: implement CONFIG_STRICT_DEVMEM by disabling access to RAM via /dev/mem")
> Fixes: 527701eda5f1 ("lib: Add a generic version of devmem_is_allowed()")
> Cc: stable@vger.kernel.org # v2.6.37
> Signed-off-by: Liang Wang <wangliang101@huawei.com>

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>

  Luis

  reply	other threads:[~2021-08-02 22:40 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-31  2:50 [PATCH v3] lib: Use PFN_PHYS() in devmem_is_allowed() Liang Wang
2021-08-02 22:40 ` Luis Chamberlain [this message]
2021-08-04  5:01 ` Kefeng Wang
2021-08-04  5:14   ` Palmer Dabbelt

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