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: Michael Wu michael@allwinnertech.com Tested-by: Michael Wu michael@allwinnertech.com Reviewed-by: John Keeping john@metanate.com Signed-off-by: Linyu Yuan quic_linyyuan@quicinc.com --- v2: add Reviewed-by from John keeping v3: add Reported-by from Michael Wu v4: add Tested-by from Michael Wu cc stable kernel
drivers/usb/gadget/function/f_fs.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 3958c60..b0c046a 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1077,6 +1077,11 @@ 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 @@ -1084,6 +1089,7 @@ 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; }