From: Michael Zimmermann Date: Sun, 12 Apr 2026 01:47:15 +0000 (-0400) Subject: usb: gadget: f_hid: move list and spinlock inits from bind to alloc X-Git-Tag: v6.1.169~30 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=81aee4500055876883658b024b6fb61801afe134;p=thirdparty%2Fkernel%2Fstable.git usb: gadget: f_hid: move list and spinlock inits from bind to alloc [ Upstream commit 4e0a88254ad59f6c53a34bf5fa241884ec09e8b2 ] There was an issue when you did the following: - setup and bind an hid gadget - open /dev/hidg0 - use the resulting fd in EPOLL_CTL_ADD - unbind the UDC - bind the UDC - use the fd in EPOLL_CTL_DEL When CONFIG_DEBUG_LIST was enabled, a list_del corruption was reported within remove_wait_queue (via ep_remove_wait_queue). After some debugging I found out that the queues, which f_hid registers via poll_wait were the problem. These were initialized using init_waitqueue_head inside hidg_bind. So effectively, the bind function re-initialized the queues while there were still items in them. The solution is to move the initialization from hidg_bind to hidg_alloc to extend their lifetimes to the lifetime of the function instance. Additionally, I found many other possibly problematic init calls in the bind function, which I moved as well. Signed-off-by: Michael Zimmermann Cc: stable Link: https://patch.msgid.link/20260331184844.2388761-1-sigmaepsilon92@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c index c20d3426571ec..de00785fa183d 100644 --- a/drivers/usb/gadget/function/f_hid.c +++ b/drivers/usb/gadget/function/f_hid.c @@ -996,13 +996,8 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f) if (status) goto fail; - spin_lock_init(&hidg->write_spinlock); hidg->write_pending = 1; hidg->req = NULL; - spin_lock_init(&hidg->read_spinlock); - init_waitqueue_head(&hidg->write_queue); - init_waitqueue_head(&hidg->read_queue); - INIT_LIST_HEAD(&hidg->completed_out_req); /* create char device */ cdev_init(&hidg->cdev, &f_hidg_fops); @@ -1272,6 +1267,12 @@ static struct usb_function *hidg_alloc(struct usb_function_instance *fi) mutex_lock(&opts->lock); ++opts->refcnt; + spin_lock_init(&hidg->write_spinlock); + spin_lock_init(&hidg->read_spinlock); + init_waitqueue_head(&hidg->write_queue); + init_waitqueue_head(&hidg->read_queue); + INIT_LIST_HEAD(&hidg->completed_out_req); + device_initialize(&hidg->dev); hidg->dev.release = hidg_release; hidg->dev.class = hidg_class;