FAILED: patch "[PATCH] usb: gadget: f_rndis: Refactor bind path to use __free()" failed to apply to 6.1-stable tree

FAILED: patch "[PATCH] usb: gadget: f_rndis: Refactor bind path to use __free()" failed to apply to 6.1-stable tree

[gregkh]

The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 08228941436047bdcd35a612c1aec0912a29d8cd
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025101656-perky-popcorn-f7b0@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 08228941436047bdcd35a612c1aec0912a29d8cd Mon Sep 17 00:00:00 2001
From: Kuen-Han Tsai <khtsai@google.com>
Date: Tue, 16 Sep 2025 16:21:37 +0800
Subject: [PATCH] usb: gadget: f_rndis: Refactor bind path to use __free()

After an bind/unbind cycle, the rndis->notify_req is left stale. If a
subsequent bind fails, the unified error label attempts to free this
stale request, leading to a NULL pointer dereference when accessing
ep->ops->free_request.

Refactor the error handling in the bind path to use the __free()
automatic cleanup mechanism.

Fixes: 45fe3b8e5342 ("usb ethernet gadget: split RNDIS function")
Cc: stable@kernel.org
Signed-off-by: Kuen-Han Tsai <khtsai@google.com>
Link: https://lore.kernel.org/r/20250916-ready-v1-6-4997bf277548@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250916-ready-v1-6-4997bf277548@google.com

diff --git a/drivers/usb/gadget/function/f_rndis.c b/drivers/usb/gadget/function/f_rndis.c
index 7cec19d65fb5..7451e7cb7a85 100644
--- a/drivers/usb/gadget/function/f_rndis.c
+++ b/drivers/usb/gadget/function/f_rndis.c
@@ -19,6 +19,8 @@
 
 #include <linux/atomic.h>
 
+#include <linux/usb/gadget.h>
+
 #include "u_ether.h"
 #include "u_ether_configfs.h"
 #include "u_rndis.h"
@@ -662,6 +664,8 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 	struct usb_ep		*ep;
 
 	struct f_rndis_opts *rndis_opts;
+	struct usb_os_desc_table        *os_desc_table __free(kfree) = NULL;
+	struct usb_request		*request __free(free_usb_request) = NULL;
 
 	if (!can_support_rndis(c))
 		return -EINVAL;
@@ -669,12 +673,9 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 	rndis_opts = container_of(f->fi, struct f_rndis_opts, func_inst);
 
 	if (cdev->use_os_string) {
-		f->os_desc_table = kzalloc(sizeof(*f->os_desc_table),
-					   GFP_KERNEL);
-		if (!f->os_desc_table)
+		os_desc_table = kzalloc(sizeof(*os_desc_table), GFP_KERNEL);
+		if (!os_desc_table)
 			return -ENOMEM;
-		f->os_desc_n = 1;
-		f->os_desc_table[0].os_desc = &rndis_opts->rndis_os_desc;
 	}
 
 	rndis_iad_descriptor.bFunctionClass = rndis_opts->class;
@@ -692,16 +693,14 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 		gether_set_gadget(rndis_opts->net, cdev->gadget);
 		status = gether_register_netdev(rndis_opts->net);
 		if (status)
-			goto fail;
+			return status;
 		rndis_opts->bound = true;
 	}
 
 	us = usb_gstrings_attach(cdev, rndis_strings,
 				 ARRAY_SIZE(rndis_string_defs));
-	if (IS_ERR(us)) {
-		status = PTR_ERR(us);
-		goto fail;
-	}
+	if (IS_ERR(us))
+		return PTR_ERR(us);
 	rndis_control_intf.iInterface = us[0].id;
 	rndis_data_intf.iInterface = us[1].id;
 	rndis_iad_descriptor.iFunction = us[2].id;
@@ -709,36 +708,30 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 	/* allocate instance-specific interface IDs */
 	status = usb_interface_id(c, f);
 	if (status < 0)
-		goto fail;
+		return status;
 	rndis->ctrl_id = status;
 	rndis_iad_descriptor.bFirstInterface = status;
 
 	rndis_control_intf.bInterfaceNumber = status;
 	rndis_union_desc.bMasterInterface0 = status;
 
-	if (cdev->use_os_string)
-		f->os_desc_table[0].if_id =
-			rndis_iad_descriptor.bFirstInterface;
-
 	status = usb_interface_id(c, f);
 	if (status < 0)
-		goto fail;
+		return status;
 	rndis->data_id = status;
 
 	rndis_data_intf.bInterfaceNumber = status;
 	rndis_union_desc.bSlaveInterface0 = status;
 
-	status = -ENODEV;
-
 	/* allocate instance-specific endpoints */
 	ep = usb_ep_autoconfig(cdev->gadget, &fs_in_desc);
 	if (!ep)
-		goto fail;
+		return -ENODEV;
 	rndis->port.in_ep = ep;
 
 	ep = usb_ep_autoconfig(cdev->gadget, &fs_out_desc);
 	if (!ep)
-		goto fail;
+		return -ENODEV;
 	rndis->port.out_ep = ep;
 
 	/* NOTE:  a status/notification endpoint is, strictly speaking,
@@ -747,21 +740,19 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 	 */
 	ep = usb_ep_autoconfig(cdev->gadget, &fs_notify_desc);
 	if (!ep)
-		goto fail;
+		return -ENODEV;
 	rndis->notify = ep;
 
-	status = -ENOMEM;
-
 	/* allocate notification request and buffer */
-	rndis->notify_req = usb_ep_alloc_request(ep, GFP_KERNEL);
-	if (!rndis->notify_req)
-		goto fail;
-	rndis->notify_req->buf = kmalloc(STATUS_BYTECOUNT, GFP_KERNEL);
-	if (!rndis->notify_req->buf)
-		goto fail;
-	rndis->notify_req->length = STATUS_BYTECOUNT;
-	rndis->notify_req->context = rndis;
-	rndis->notify_req->complete = rndis_response_complete;
+	request = usb_ep_alloc_request(ep, GFP_KERNEL);
+	if (!request)
+		return -ENOMEM;
+	request->buf = kmalloc(STATUS_BYTECOUNT, GFP_KERNEL);
+	if (!request->buf)
+		return -ENOMEM;
+	request->length = STATUS_BYTECOUNT;
+	request->context = rndis;
+	request->complete = rndis_response_complete;
 
 	/* support all relevant hardware speeds... we expect that when
 	 * hardware is dual speed, all bulk-capable endpoints work at
@@ -778,7 +769,7 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 	status = usb_assign_descriptors(f, eth_fs_function, eth_hs_function,
 			eth_ss_function, eth_ss_function);
 	if (status)
-		goto fail;
+		return status;
 
 	rndis->port.open = rndis_open;
 	rndis->port.close = rndis_close;
@@ -789,10 +780,19 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 	if (rndis->manufacturer && rndis->vendorID &&
 			rndis_set_param_vendor(rndis->params, rndis->vendorID,
 					       rndis->manufacturer)) {
-		status = -EINVAL;
-		goto fail_free_descs;
+		usb_free_all_descriptors(f);
+		return -EINVAL;
 	}
 
+	if (cdev->use_os_string) {
+		os_desc_table[0].os_desc = &rndis_opts->rndis_os_desc;
+		os_desc_table[0].if_id = rndis_iad_descriptor.bFirstInterface;
+		f->os_desc_table = no_free_ptr(os_desc_table);
+		f->os_desc_n = 1;
+
+	}
+	rndis->notify_req = no_free_ptr(request);
+
 	/* NOTE:  all that is done without knowing or caring about
 	 * the network link ... which is unavailable to this code
 	 * until we're activated via set_alt().
@@ -802,21 +802,6 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 			rndis->port.in_ep->name, rndis->port.out_ep->name,
 			rndis->notify->name);
 	return 0;
-
-fail_free_descs:
-	usb_free_all_descriptors(f);
-fail:
-	kfree(f->os_desc_table);
-	f->os_desc_n = 0;
-
-	if (rndis->notify_req) {
-		kfree(rndis->notify_req->buf);
-		usb_ep_free_request(rndis->notify, rndis->notify_req);
-	}
-
-	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
-
-	return status;
 }
 
 void rndis_borrow_net(struct usb_function_instance *f, struct net_device *net)

[PATCH 6.1.y 1/3] usb: gadget: Store endpoint pointer in usb_request

[Sasha Levin]

From: Kuen-Han Tsai <khtsai@google.com>

[ Upstream commit bfb1d99d969fe3b892db30848aeebfa19d21f57f ]

Gadget function drivers often have goto-based error handling in their
bind paths, which can be bug-prone. Refactoring these paths to use
__free() scope-based cleanup is desirable, but currently blocked.

The blocker is that usb_ep_free_request(ep, req) requires two
parameters, while the __free() mechanism can only pass a pointer to the
request itself.

Store an endpoint pointer in the struct usb_request. The pointer is
populated centrally in usb_ep_alloc_request() on every successful
allocation, making the request object self-contained.

Signed-off-by: Kuen-Han Tsai <khtsai@google.com>
Link: https://lore.kernel.org/r/20250916-ready-v1-1-4997bf277548@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250916-ready-v1-1-4997bf277548@google.com
Stable-dep-of: 082289414360 ("usb: gadget: f_rndis: Refactor bind path to use __free()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/gadget/udc/core.c | 3 +++
 include/linux/usb/gadget.h    | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index 5adb6e831126a..d98da3c44ff5e 100644
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -194,6 +194,9 @@ struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,
 
 	req = ep->ops->alloc_request(ep, gfp_flags);
 
+	if (req)
+		req->ep = ep;
+
 	trace_usb_ep_alloc_request(ep, req, req ? 0 : -ENOMEM);
 
 	return req;
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 705b76f8dddb2..9a4d800cdc1e3 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -31,6 +31,7 @@ struct usb_ep;
 
 /**
  * struct usb_request - describes one i/o request
+ * @ep: The associated endpoint set by usb_ep_alloc_request().
  * @buf: Buffer used for data.  Always provide this; some controllers
  *	only use PIO, or don't use DMA for some endpoints.
  * @dma: DMA address corresponding to 'buf'.  If you don't set this
@@ -96,6 +97,7 @@ struct usb_ep;
  */
 
 struct usb_request {
+	struct usb_ep		*ep;
 	void			*buf;
 	unsigned		length;
 	dma_addr_t		dma;
-- 
2.51.0

[PATCH 6.1.y 2/3] usb: gadget: Introduce free_usb_request helper

[Sasha Levin]

From: Kuen-Han Tsai <khtsai@google.com>

[ Upstream commit 201c53c687f2b55a7cc6d9f4000af4797860174b ]

Introduce the free_usb_request() function that frees both the request's
buffer and the request itself.

This function serves as the cleanup callback for DEFINE_FREE() to enable
automatic, scope-based cleanup for usb_request pointers.

Signed-off-by: Kuen-Han Tsai <khtsai@google.com>
Link: https://lore.kernel.org/r/20250916-ready-v1-2-4997bf277548@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250916-ready-v1-2-4997bf277548@google.com
Stable-dep-of: 082289414360 ("usb: gadget: f_rndis: Refactor bind path to use __free()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/usb/gadget.h | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 9a4d800cdc1e3..2cae3af9742d3 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -15,6 +15,7 @@
 #ifndef __LINUX_USB_GADGET_H
 #define __LINUX_USB_GADGET_H
 
+#include <linux/cleanup.h>
 #include <linux/device.h>
 #include <linux/errno.h>
 #include <linux/init.h>
@@ -290,6 +291,28 @@ static inline void usb_ep_fifo_flush(struct usb_ep *ep)
 
 /*-------------------------------------------------------------------------*/
 
+/**
+ * free_usb_request - frees a usb_request object and its buffer
+ * @req: the request being freed
+ *
+ * This helper function frees both the request's buffer and the request object
+ * itself by calling usb_ep_free_request(). Its signature is designed to be used
+ * with DEFINE_FREE() to enable automatic, scope-based cleanup for usb_request
+ * pointers.
+ */
+static inline void free_usb_request(struct usb_request *req)
+{
+	if (!req)
+		return;
+
+	kfree(req->buf);
+	usb_ep_free_request(req->ep, req);
+}
+
+DEFINE_FREE(free_usb_request, struct usb_request *, free_usb_request(_T))
+
+/*-------------------------------------------------------------------------*/
+
 struct usb_dcd_config_params {
 	__u8  bU1devExitLat;	/* U1 Device exit Latency */
 #define USB_DEFAULT_U1_DEV_EXIT_LAT	0x01	/* Less then 1 microsec */
-- 
2.51.0

[PATCH 6.1.y 3/3] usb: gadget: f_rndis: Refactor bind path to use __free()

[Sasha Levin]

From: Kuen-Han Tsai <khtsai@google.com>

[ Upstream commit 08228941436047bdcd35a612c1aec0912a29d8cd ]

After an bind/unbind cycle, the rndis->notify_req is left stale. If a
subsequent bind fails, the unified error label attempts to free this
stale request, leading to a NULL pointer dereference when accessing
ep->ops->free_request.

Refactor the error handling in the bind path to use the __free()
automatic cleanup mechanism.

Fixes: 45fe3b8e5342 ("usb ethernet gadget: split RNDIS function")
Cc: stable@kernel.org
Signed-off-by: Kuen-Han Tsai <khtsai@google.com>
Link: https://lore.kernel.org/r/20250916-ready-v1-6-4997bf277548@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250916-ready-v1-6-4997bf277548@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/gadget/function/f_rndis.c | 85 +++++++++++----------------
 1 file changed, 35 insertions(+), 50 deletions(-)

diff --git a/drivers/usb/gadget/function/f_rndis.c b/drivers/usb/gadget/function/f_rndis.c
index ee95e8f5f9d48..1dbda4e98ac43 100644
--- a/drivers/usb/gadget/function/f_rndis.c
+++ b/drivers/usb/gadget/function/f_rndis.c
@@ -19,6 +19,8 @@
 
 #include <linux/atomic.h>
 
+#include <linux/usb/gadget.h>
+
 #include "u_ether.h"
 #include "u_ether_configfs.h"
 #include "u_rndis.h"
@@ -675,6 +677,8 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 	struct usb_ep		*ep;
 
 	struct f_rndis_opts *rndis_opts;
+	struct usb_os_desc_table        *os_desc_table __free(kfree) = NULL;
+	struct usb_request		*request __free(free_usb_request) = NULL;
 
 	if (!can_support_rndis(c))
 		return -EINVAL;
@@ -682,12 +686,9 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 	rndis_opts = container_of(f->fi, struct f_rndis_opts, func_inst);
 
 	if (cdev->use_os_string) {
-		f->os_desc_table = kzalloc(sizeof(*f->os_desc_table),
-					   GFP_KERNEL);
-		if (!f->os_desc_table)
+		os_desc_table = kzalloc(sizeof(*os_desc_table), GFP_KERNEL);
+		if (!os_desc_table)
 			return -ENOMEM;
-		f->os_desc_n = 1;
-		f->os_desc_table[0].os_desc = &rndis_opts->rndis_os_desc;
 	}
 
 	rndis_iad_descriptor.bFunctionClass = rndis_opts->class;
@@ -705,16 +706,14 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 		gether_set_gadget(rndis_opts->net, cdev->gadget);
 		status = gether_register_netdev(rndis_opts->net);
 		if (status)
-			goto fail;
+			return status;
 		rndis_opts->bound = true;
 	}
 
 	us = usb_gstrings_attach(cdev, rndis_strings,
 				 ARRAY_SIZE(rndis_string_defs));
-	if (IS_ERR(us)) {
-		status = PTR_ERR(us);
-		goto fail;
-	}
+	if (IS_ERR(us))
+		return PTR_ERR(us);
 	rndis_control_intf.iInterface = us[0].id;
 	rndis_data_intf.iInterface = us[1].id;
 	rndis_iad_descriptor.iFunction = us[2].id;
@@ -722,36 +721,30 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 	/* allocate instance-specific interface IDs */
 	status = usb_interface_id(c, f);
 	if (status < 0)
-		goto fail;
+		return status;
 	rndis->ctrl_id = status;
 	rndis_iad_descriptor.bFirstInterface = status;
 
 	rndis_control_intf.bInterfaceNumber = status;
 	rndis_union_desc.bMasterInterface0 = status;
 
-	if (cdev->use_os_string)
-		f->os_desc_table[0].if_id =
-			rndis_iad_descriptor.bFirstInterface;
-
 	status = usb_interface_id(c, f);
 	if (status < 0)
-		goto fail;
+		return status;
 	rndis->data_id = status;
 
 	rndis_data_intf.bInterfaceNumber = status;
 	rndis_union_desc.bSlaveInterface0 = status;
 
-	status = -ENODEV;
-
 	/* allocate instance-specific endpoints */
 	ep = usb_ep_autoconfig(cdev->gadget, &fs_in_desc);
 	if (!ep)
-		goto fail;
+		return -ENODEV;
 	rndis->port.in_ep = ep;
 
 	ep = usb_ep_autoconfig(cdev->gadget, &fs_out_desc);
 	if (!ep)
-		goto fail;
+		return -ENODEV;
 	rndis->port.out_ep = ep;
 
 	/* NOTE:  a status/notification endpoint is, strictly speaking,
@@ -760,21 +753,19 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 	 */
 	ep = usb_ep_autoconfig(cdev->gadget, &fs_notify_desc);
 	if (!ep)
-		goto fail;
+		return -ENODEV;
 	rndis->notify = ep;
 
-	status = -ENOMEM;
-
 	/* allocate notification request and buffer */
-	rndis->notify_req = usb_ep_alloc_request(ep, GFP_KERNEL);
-	if (!rndis->notify_req)
-		goto fail;
-	rndis->notify_req->buf = kmalloc(STATUS_BYTECOUNT, GFP_KERNEL);
-	if (!rndis->notify_req->buf)
-		goto fail;
-	rndis->notify_req->length = STATUS_BYTECOUNT;
-	rndis->notify_req->context = rndis;
-	rndis->notify_req->complete = rndis_response_complete;
+	request = usb_ep_alloc_request(ep, GFP_KERNEL);
+	if (!request)
+		return -ENOMEM;
+	request->buf = kmalloc(STATUS_BYTECOUNT, GFP_KERNEL);
+	if (!request->buf)
+		return -ENOMEM;
+	request->length = STATUS_BYTECOUNT;
+	request->context = rndis;
+	request->complete = rndis_response_complete;
 
 	/* support all relevant hardware speeds... we expect that when
 	 * hardware is dual speed, all bulk-capable endpoints work at
@@ -791,7 +782,7 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 	status = usb_assign_descriptors(f, eth_fs_function, eth_hs_function,
 			eth_ss_function, eth_ss_function);
 	if (status)
-		goto fail;
+		return status;
 
 	rndis->port.open = rndis_open;
 	rndis->port.close = rndis_close;
@@ -802,9 +793,18 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 	if (rndis->manufacturer && rndis->vendorID &&
 			rndis_set_param_vendor(rndis->params, rndis->vendorID,
 					       rndis->manufacturer)) {
-		status = -EINVAL;
-		goto fail_free_descs;
+		usb_free_all_descriptors(f);
+		return -EINVAL;
+	}
+
+	if (cdev->use_os_string) {
+		os_desc_table[0].os_desc = &rndis_opts->rndis_os_desc;
+		os_desc_table[0].if_id = rndis_iad_descriptor.bFirstInterface;
+		f->os_desc_table = no_free_ptr(os_desc_table);
+		f->os_desc_n = 1;
+
 	}
+	rndis->notify_req = no_free_ptr(request);
 
 	/* NOTE:  all that is done without knowing or caring about
 	 * the network link ... which is unavailable to this code
@@ -817,21 +817,6 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f)
 			rndis->port.in_ep->name, rndis->port.out_ep->name,
 			rndis->notify->name);
 	return 0;
-
-fail_free_descs:
-	usb_free_all_descriptors(f);
-fail:
-	kfree(f->os_desc_table);
-	f->os_desc_n = 0;
-
-	if (rndis->notify_req) {
-		kfree(rndis->notify_req->buf);
-		usb_ep_free_request(rndis->notify, rndis->notify_req);
-	}
-
-	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
-
-	return status;
 }
 
 void rndis_borrow_net(struct usb_function_instance *f, struct net_device *net)
-- 
2.51.0