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Message-ID: <Yi4dOxArKLNyMFZy@builder.lan>
Date: Sun, 13 Mar 2022 11:35:07 -0500
From: Bjorn Andersson <bjorn.andersson@...aro.org>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Rafael J. Wysocki" <rafael@...nel.org>,
Stuart Yoder <stuyoder@...il.com>,
Laurentiu Tudor <laurentiu.tudor@....com>,
Abel Vesa <abel.vesa@....com>, Shawn Guo <shawnguo@...nel.org>,
Sascha Hauer <s.hauer@...gutronix.de>,
Fabio Estevam <festevam@...il.com>,
"K. Y. Srinivasan" <kys@...rosoft.com>,
Haiyang Zhang <haiyangz@...rosoft.com>,
Stephen Hemminger <sthemmin@...rosoft.com>,
Wei Liu <wei.liu@...nel.org>, Dexuan Cui <decui@...rosoft.com>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Mathieu Poirier <mathieu.poirier@...aro.org>,
Vineeth Vijayan <vneethv@...ux.ibm.com>,
Peter Oberparleiter <oberpar@...ux.ibm.com>,
Heiko Carstens <hca@...ux.ibm.com>,
Vasily Gorbik <gor@...ux.ibm.com>,
Alexander Gordeev <agordeev@...ux.ibm.com>,
Christian Borntraeger <borntraeger@...ux.ibm.com>,
Sven Schnelle <svens@...ux.ibm.com>,
Andy Gross <agross@...nel.org>,
Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
Mark Brown <broonie@...nel.org>,
"Michael S. Tsirkin" <mst@...hat.com>,
Jason Wang <jasowang@...hat.com>, linux-kernel@...r.kernel.org,
linux-clk@...r.kernel.org, NXP Linux Team <linux-imx@....com>,
linux-arm-kernel@...ts.infradead.org, linux-hyperv@...r.kernel.org,
linux-pci@...r.kernel.org, linux-remoteproc@...r.kernel.org,
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alsa-devel@...a-project.org, linux-spi@...r.kernel.org,
virtualization@...ts.linux-foundation.org,
Linus Torvalds <torvalds@...ux-foundation.org>,
Rasmus Villemoes <linux@...musvillemoes.dk>,
stable@...r.kernel.org
Subject: Re: [PATCH v4 11/11] rpmsg: Fix kfree() of static memory on setting
driver_override
On Sat 12 Mar 07:28 CST 2022, Krzysztof Kozlowski wrote:
> The driver_override field from platform driver should not be initialized
> from static memory (string literal) because the core later kfree() it,
> for example when driver_override is set via sysfs.
>
> Use dedicated helper to set driver_override properly.
>
> Fixes: 950a7388f02b ("rpmsg: Turn name service into a stand alone driver")
> Fixes: c0cdc19f84a4 ("rpmsg: Driver for user space endpoint interface")
> Cc: <stable@...r.kernel.org>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@...aro.org>
Regards,
Bjorn
> ---
> drivers/rpmsg/rpmsg_core.c | 3 ++-
> drivers/rpmsg/rpmsg_internal.h | 13 +++++++++++--
> drivers/rpmsg/rpmsg_ns.c | 14 ++++++++++++--
> include/linux/rpmsg.h | 6 ++++--
> 4 files changed, 29 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
> index d9e612f4f0f2..6e2bf2742973 100644
> --- a/drivers/rpmsg/rpmsg_core.c
> +++ b/drivers/rpmsg/rpmsg_core.c
> @@ -397,7 +397,8 @@ field##_store(struct device *dev, struct device_attribute *attr, \
> const char *buf, size_t sz) \
> { \
> struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
> - char *new, *old; \
> + const char *old; \
> + char *new; \
> \
> new = kstrndup(buf, sz, GFP_KERNEL); \
> if (!new) \
> diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
> index b1245d3ed7c6..31345d6e9a7e 100644
> --- a/drivers/rpmsg/rpmsg_internal.h
> +++ b/drivers/rpmsg/rpmsg_internal.h
> @@ -92,10 +92,19 @@ int rpmsg_release_channel(struct rpmsg_device *rpdev,
> */
> static inline int rpmsg_chrdev_register_device(struct rpmsg_device *rpdev)
> {
> + int ret;
> +
> strcpy(rpdev->id.name, "rpmsg_chrdev");
> - rpdev->driver_override = "rpmsg_chrdev";
> + ret = driver_set_override(&rpdev->dev, &rpdev->driver_override,
> + "rpmsg_chrdev", strlen("rpmsg_chrdev"));
> + if (ret)
> + return ret;
> +
> + ret = rpmsg_register_device(rpdev);
> + if (ret)
> + kfree(rpdev->driver_override);
>
> - return rpmsg_register_device(rpdev);
> + return ret;
> }
>
> #endif
> diff --git a/drivers/rpmsg/rpmsg_ns.c b/drivers/rpmsg/rpmsg_ns.c
> index 762ff1ae279f..95a51543f5ad 100644
> --- a/drivers/rpmsg/rpmsg_ns.c
> +++ b/drivers/rpmsg/rpmsg_ns.c
> @@ -20,12 +20,22 @@
> */
> int rpmsg_ns_register_device(struct rpmsg_device *rpdev)
> {
> + int ret;
> +
> strcpy(rpdev->id.name, "rpmsg_ns");
> - rpdev->driver_override = "rpmsg_ns";
> + ret = driver_set_override(&rpdev->dev, &rpdev->driver_override,
> + "rpmsg_ns", strlen("rpmsg_ns"));
> + if (ret)
> + return ret;
> +
> rpdev->src = RPMSG_NS_ADDR;
> rpdev->dst = RPMSG_NS_ADDR;
>
> - return rpmsg_register_device(rpdev);
> + ret = rpmsg_register_device(rpdev);
> + if (ret)
> + kfree(rpdev->driver_override);
> +
> + return ret;
> }
> EXPORT_SYMBOL(rpmsg_ns_register_device);
>
> diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
> index 02fa9116cd60..20c8cd1cde21 100644
> --- a/include/linux/rpmsg.h
> +++ b/include/linux/rpmsg.h
> @@ -41,7 +41,9 @@ struct rpmsg_channel_info {
> * rpmsg_device - device that belong to the rpmsg bus
> * @dev: the device struct
> * @id: device id (used to match between rpmsg drivers and devices)
> - * @driver_override: driver name to force a match
> + * @driver_override: driver name to force a match; do not set directly,
> + * because core frees it; use driver_set_override() to
> + * set or clear it.
> * @src: local address
> * @dst: destination address
> * @ept: the rpmsg endpoint of this channel
> @@ -51,7 +53,7 @@ struct rpmsg_channel_info {
> struct rpmsg_device {
> struct device dev;
> struct rpmsg_device_id id;
> - char *driver_override;
> + const char *driver_override;
> u32 src;
> u32 dst;
> struct rpmsg_endpoint *ept;
> --
> 2.32.0
>
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