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

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If a task read/write data in blocking mode, it will wait the completion
in ffs_epfile_io(), if function unbind occurs, ffs_func_unbind() will
kfree ffs ep, once the task wake up, it still dereference the ffs ep to
obtain the request status.

Fix it by moving the request status to io_data which is stack-safe.

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/1654863478-26228-2-git-send-email-quic_linyyuan@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

(cherry picked from commit fb1f16d74e263baa4ad11e31e28b68f144aa55ed
https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git/ usb-next)

Bug: 237482099
Change-Id: I439b94c4fbc56416c3339ada5f066aa606fd81bd
Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
This commit is contained in:
Krishna Kurapati
2022-06-28 00:03:39 +05:30
parent abb407e9ff
commit 7d2bd28eae
1 changed files with 19 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
drivers/usb/gadget/function/f_fs.c
View File

@@ -122,8 +122,6 @@ struct ffs_ep {
struct usb_endpoint_descriptor *descs[3];
u8 num;
int status; /* P: epfile->mutex */
};
struct ffs_epfile {
@@ -227,6 +225,9 @@ struct ffs_io_data {
bool use_sg;
struct ffs_data *ffs;
int status;
struct completion done;
};
struct ffs_desc_helper {
@@ -705,12 +706,15 @@ static const struct file_operations ffs_ep0_operations = {
static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
{
struct ffs_io_data *io_data = req->context;
ENTER();
if (likely(req->context)) {
struct ffs_ep *ep = _ep->driver_data;
ep->status = req->status ? req->status : req->actual;
complete(req->context);
}
if (req->status)
io_data->status = req->status;
else
io_data->status = req->actual;
complete(&io_data->done);
}
static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
@@ -1048,7 +1052,6 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
WARN(1, "%s: data_len == -EINVAL\n", __func__);
ret = -EINVAL;
} else if (!io_data->aio) {
DECLARE_COMPLETION_ONSTACK(done);
bool interrupted = false;
req = ep->req;
@@ -1064,7 +1067,8 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
io_data->buf = data;
req->context = &done;
init_completion(&io_data->done);
req->context = io_data;
req->complete = ffs_epfile_io_complete;
ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
@@ -1073,7 +1077,7 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
spin_unlock_irq(&epfile->ffs->eps_lock);
if (unlikely(wait_for_completion_interruptible(&done))) {
if (unlikely(wait_for_completion_interruptible(&io_data->done))) {
/*
* To avoid race condition with ffs_epfile_io_complete,
* dequeue the request first then check
@@ -1081,17 +1085,17 @@ 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);
wait_for_completion(&done);
interrupted = ep->status < 0;
wait_for_completion(&io_data->done);
interrupted = io_data->status < 0;
}
if (interrupted)
ret = -EINTR;
else if (io_data->read && ep->status > 0)
ret = __ffs_epfile_read_data(epfile, data, ep->status,
else if (io_data->read && io_data->status > 0)
ret = __ffs_epfile_read_data(epfile, data, io_data->status,
&io_data->data);
else
ret = ep->status;
ret = io_data->status;
goto error_mutex;
} else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
ret = -ENOMEM;