From: Yicong Yang <yangyicong@hisilicon.com>
To: <tudor.ambarus@microchip.com>, <linux-mtd@lists.infradead.org>
Cc: vigneshr@ti.com, chenxiang66@hisilicon.com, richard@nod.at,
john.garry@huawei.com, linuxarm@huawei.com,
miquel.raynal@bootlin.com
Subject: Re: [PATCH] mtd:spi-nor: Fix an issue of releasing resources during read/write
Date: Mon, 15 Jun 2020 17:18:04 +0800 [thread overview]
Message-ID: <de34a767-c9b4-55c3-5a2c-3cda8008d77b@hisilicon.com> (raw)
In-Reply-To: <1589542063-6703-1-git-send-email-yangyicong@hisilicon.com>
A friendly ping...
Thanks.
On 2020/5/15 19:27, Yicong Yang wrote:
> From: Xiang Chen <chenxiang66@hisilicon.com>
>
> If rmmod the driver during read or write, the driver will release the
> resources which are used during read or write, so it is possible to
> refer to NULL pointer.
>
> Use the testcase "mtd_debug read /dev/mtd0 0xc00000 0x400000 dest_file &
> sleep 0.5;rmmod spi_hisi_sfc_v3xx.ko", the issue can be reproduced in
> hisi_sfc_v3xx driver.
>
> To avoid the issue, fill the interface _get_device and _put_device of
> mtd_info to grab the reference to the spi controller driver module, so
> the request of rmmod the driver is rejected before read/write is finished.
>
> Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
> ---
> The patch has been tested with hisi_sfc_v3xx controller. May someone
> could test it on a spi-nor-controller device as we don't have one
> aside.
>
> drivers/mtd/spi-nor/core.c | 33 +++++++++++++++++++++++++++++++++
> 1 file changed, 33 insertions(+)
>
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index cc68ea8..05370cb 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -2977,6 +2977,37 @@ static void spi_nor_resume(struct mtd_info *mtd)
> dev_err(dev, "resume() failed\n");
> }
>
> +static int spi_nor_get_device(struct mtd_info *mtd)
> +{
> + struct mtd_info *master = mtd_get_master(mtd);
> + struct spi_nor *nor = mtd_to_spi_nor(master);
> + struct device *dev;
> +
> + if (nor->spimem)
> + dev = nor->spimem->spi->controller->dev.parent;
> + else
> + dev = nor->dev;
> +
> + if (!try_module_get(dev->driver->owner))
> + return -ENODEV;
> +
> + return 0;
> +}
> +
> +static void spi_nor_put_device(struct mtd_info *mtd)
> +{
> + struct mtd_info *master = mtd_get_master(mtd);
> + struct spi_nor *nor = mtd_to_spi_nor(master);
> + struct device *dev;
> +
> + if (nor->spimem)
> + dev = nor->spimem->spi->controller->dev.parent;
> + else
> + dev = nor->dev;
> +
> + module_put(dev->driver->owner);
> +}
> +
> void spi_nor_restore(struct spi_nor *nor)
> {
> /* restore the addressing mode */
> @@ -3151,6 +3182,8 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
> mtd->_erase = spi_nor_erase;
> mtd->_read = spi_nor_read;
> mtd->_resume = spi_nor_resume;
> + mtd->_get_device = spi_nor_get_device;
> + mtd->_put_device = spi_nor_put_device;
>
> if (nor->params->locking_ops) {
> mtd->_lock = spi_nor_lock;
> --
> 2.8.1
>
> .
>
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prev parent reply other threads:[~2020-06-15 9:25 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 11:27 [PATCH] mtd:spi-nor: Fix an issue of releasing resources during read/write Yicong Yang
2020-06-15 9:18 ` Yicong Yang [this message]
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