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 42988380ac67c76bb9dff8f77d7ef3eefd50b7b5 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025101600-epidemic-bleak-5192@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 42988380ac67c76bb9dff8f77d7ef3eefd50b7b5 Mon Sep 17 00:00:00 2001 From: Kuen-Han Tsai khtsai@google.com Date: Tue, 16 Sep 2025 16:21:36 +0800 Subject: [PATCH] usb: gadget: f_ecm: Refactor bind path to use __free()

After an bind/unbind cycle, the ecm->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: da741b8c56d6 ("usb ethernet gadget: split CDC Ethernet function") Cc: stable@kernel.org Signed-off-by: Kuen-Han Tsai khtsai@google.com Link: https://lore.kernel.org/r/20250916-ready-v1-5-4997bf277548@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Link: https://lore.kernel.org/r/20250916-ready-v1-5-4997bf277548@google.com

diff --git a/drivers/usb/gadget/function/f_ecm.c b/drivers/usb/gadget/function/f_ecm.c index 027226325039..675d2bc538a4 100644 --- a/drivers/usb/gadget/function/f_ecm.c +++ b/drivers/usb/gadget/function/f_ecm.c @@ -8,6 +8,7 @@

/* #define VERBOSE_DEBUG */

+#include <linux/cleanup.h> #include <linux/slab.h> #include <linux/kernel.h> #include <linux/module.h> @@ -15,6 +16,8 @@ #include <linux/etherdevice.h> #include <linux/string_choices.h>

+#include <linux/usb/gadget.h> + #include "u_ether.h" #include "u_ether_configfs.h" #include "u_ecm.h" @@ -678,6 +681,7 @@ ecm_bind(struct usb_configuration *c, struct usb_function *f) struct usb_ep *ep;

struct f_ecm_opts *ecm_opts; + struct usb_request *request __free(free_usb_request) = NULL;

if (!can_support_ecm(cdev->gadget)) return -EINVAL; @@ -711,7 +715,7 @@ ecm_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; ecm->ctrl_id = status; ecm_iad_descriptor.bFirstInterface = status;

@@ -720,24 +724,22 @@ ecm_bind(struct usb_configuration *c, struct usb_function *f)

status = usb_interface_id(c, f); if (status < 0) - goto fail; + return status; ecm->data_id = status;

ecm_data_nop_intf.bInterfaceNumber = status; ecm_data_intf.bInterfaceNumber = status; ecm_union_desc.bSlaveInterface0 = status;

- status = -ENODEV; - /* allocate instance-specific endpoints */ ep = usb_ep_autoconfig(cdev->gadget, &fs_ecm_in_desc); if (!ep) - goto fail; + return -ENODEV; ecm->port.in_ep = ep;

ep = usb_ep_autoconfig(cdev->gadget, &fs_ecm_out_desc); if (!ep) - goto fail; + return -ENODEV; ecm->port.out_ep = ep;

/* NOTE: a status/notification endpoint is *OPTIONAL* but we @@ -746,20 +748,18 @@ ecm_bind(struct usb_configuration *c, struct usb_function *f) */ ep = usb_ep_autoconfig(cdev->gadget, &fs_ecm_notify_desc); if (!ep) - goto fail; + return -ENODEV; ecm->notify = ep;

- status = -ENOMEM; - /* allocate notification request and buffer */ - ecm->notify_req = usb_ep_alloc_request(ep, GFP_KERNEL); - if (!ecm->notify_req) - goto fail; - ecm->notify_req->buf = kmalloc(ECM_STATUS_BYTECOUNT, GFP_KERNEL); - if (!ecm->notify_req->buf) - goto fail; - ecm->notify_req->context = ecm; - ecm->notify_req->complete = ecm_notify_complete; + request = usb_ep_alloc_request(ep, GFP_KERNEL); + if (!request) + return -ENOMEM; + request->buf = kmalloc(ECM_STATUS_BYTECOUNT, GFP_KERNEL); + if (!request->buf) + return -ENOMEM; + request->context = ecm; + request->complete = ecm_notify_complete;

/* support all relevant hardware speeds... we expect that when * hardware is dual speed, all bulk-capable endpoints work at @@ -778,7 +778,7 @@ ecm_bind(struct usb_configuration *c, struct usb_function *f) status = usb_assign_descriptors(f, ecm_fs_function, ecm_hs_function, ecm_ss_function, ecm_ss_function); if (status) - goto fail; + return status;

/* NOTE: all that is done without knowing or caring about * the network link ... which is unavailable to this code @@ -788,20 +788,12 @@ ecm_bind(struct usb_configuration *c, struct usb_function *f) ecm->port.open = ecm_open; ecm->port.close = ecm_close;

+ ecm->notify_req = no_free_ptr(request); + DBG(cdev, "CDC Ethernet: IN/%s OUT/%s NOTIFY/%s\n", ecm->port.in_ep->name, ecm->port.out_ep->name, ecm->notify->name); return 0; - -fail: - if (ecm->notify_req) { - kfree(ecm->notify_req->buf); - usb_ep_free_request(ecm->notify, ecm->notify_req); - } - - ERROR(cdev, "%s: can't bind, err %d\n", f->name, status); - - return status; }

static inline struct f_ecm_opts *to_f_ecm_opts(struct config_item *item)