Commit 0698f020 authored by Linyu Yuan's avatar Linyu Yuan Committed by Greg Kroah-Hartman
Browse files

usb: gadget: f_fs: change ep->ep safe in ffs_epfile_io() 



In ffs_epfile_io(), when read/write data in blocking mode, it will wait
the completion in interruptible mode, if task receive a signal, it will
terminate the wait, at same time, if function unbind occurs,
ffs_func_unbind() will kfree all eps, ffs_epfile_io() still try to
dequeue request by dereferencing ep which may become invalid.

Fix it by add ep spinlock and will not dereference ep if it is not valid.

Cc: <stable@vger.kernel.org> # 5.15
Reported-by: default avatarMichael Wu <michael@allwinnertech.com>
Tested-by: default avatarMichael Wu <michael@allwinnertech.com>
Reviewed-by: default avatarJohn Keeping <john@metanate.com>
Signed-off-by: default avatarLinyu Yuan <quic_linyyuan@quicinc.com>
Link: https://lore.kernel.org/r/1654863478-26228-3-git-send-email-quic_linyyuan@quicinc.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent fb1f16d7

drivers/usb/gadget/function/f_fs.c

+6 −0
Original line number Diff line number Diff line
@@ -1080,6 +1080,11 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) 
		spin_unlock_irq(&epfile->ffs->eps_lock);



		if (wait_for_completion_interruptible(&io_data->done)) {

			spin_lock_irq(&epfile->ffs->eps_lock);

			if (epfile->ep != ep) {

				ret = -ESHUTDOWN;

				goto error_lock;

			}

			/*

			 * To avoid race condition with ffs_epfile_io_complete,

			 * dequeue the request first then check
@@ -1087,6 +1092,7 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) 
			 * condition with req->complete callback.

			 */

			usb_ep_dequeue(ep->ep, req);

			spin_unlock_irq(&epfile->ffs->eps_lock);

			wait_for_completion(&io_data->done);

			interrupted = io_data->status < 0;

		}