This is a note to let you know that I've just added the patch titled
usb: gadget: f_fs: change ep->ep safe in ffs_epfile_io()
to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-linus branch.
The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.
If you have any questions about this process, please let me know.
From 0698f0209d8032e8869525aeb68f65ee7fde12ad Mon Sep 17 00:00:00 2001 From: Linyu Yuan quic_linyyuan@quicinc.com Date: Fri, 10 Jun 2022 20:17:58 +0800 Subject: 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: 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 Link: https://lore.kernel.org/r/1654863478-26228-3-git-send-email-quic_linyyuan@qu... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 e1fcd8bc80a1..e0fa4b186ec6 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -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; }