Commit 4e0a8825 authored by Michael Zimmermann's avatar Michael Zimmermann Committed by Greg Kroah-Hartman
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usb: gadget: f_hid: move list and spinlock inits from bind to alloc 



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: default avatarMichael Zimmermann <sigmaepsilon92@gmail.com>
Cc: stable <stable@kernel.org>
Link: https://patch.msgid.link/20260331184844.2388761-1-sigmaepsilon92@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5abbe6ec

drivers/usb/gadget/function/f_hid.c

+10 −9
Original line number Diff line number Diff line
@@ -1262,17 +1262,8 @@ 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);

	spin_lock_init(&hidg->get_report_spinlock);

	init_waitqueue_head(&hidg->write_queue);

	init_waitqueue_head(&hidg->read_queue);

	init_waitqueue_head(&hidg->get_queue);

	init_waitqueue_head(&hidg->get_id_queue);

	INIT_LIST_HEAD(&hidg->completed_out_req);

	INIT_LIST_HEAD(&hidg->report_list);



	INIT_WORK(&hidg->work, get_report_workqueue_handler);

	hidg->workqueue = alloc_workqueue("report_work",
@@ -1608,6 +1599,16 @@ static struct usb_function *hidg_alloc(struct usb_function_instance *fi) 


	mutex_lock(&opts->lock);



	spin_lock_init(&hidg->write_spinlock);

	spin_lock_init(&hidg->read_spinlock);

	spin_lock_init(&hidg->get_report_spinlock);

	init_waitqueue_head(&hidg->write_queue);

	init_waitqueue_head(&hidg->read_queue);

	init_waitqueue_head(&hidg->get_queue);

	init_waitqueue_head(&hidg->get_id_queue);

	INIT_LIST_HEAD(&hidg->completed_out_req);

	INIT_LIST_HEAD(&hidg->report_list);



	device_initialize(&hidg->dev);

	hidg->dev.release = hidg_release;

	hidg->dev.class = &hidg_class;