Yoshihiro Shimoda e752dbc59e usb: gadget: udc: renesas_usb3: Fix a race in usb3_start_pipen()
The usb3_start_pipen() is called by renesas_usb3_ep_queue() and
usb3_request_done_pipen() so that usb3_start_pipen() is possible
to cause a race when getting usb3_first_req like below:

renesas_usb3_ep_queue()
 spin_lock_irqsave()
 list_add_tail()
 spin_unlock_irqrestore()
 usb3_start_pipen()
  usb3_first_req = usb3_get_request() --- [1]
 --- interrupt ---
 usb3_irq_dma_int()
 usb3_request_done_pipen()
  usb3_get_request()
  usb3_start_pipen()
  usb3_first_req = usb3_get_request()
  ...
  (the req is possible to be finished in the interrupt)

The usb3_first_req [1] above may have been finished after the interrupt
ended so that this driver caused to start a transfer wrongly. To fix this
issue, getting/checking the usb3_first_req are under spin_lock_irqsave()
in the same section.

Fixes: 746bfe63bb ("usb: gadget: renesas_usb3: add support for Renesas USB3.0 peripheral controller")
Cc: stable <[email protected]>
Signed-off-by: Yoshihiro Shimoda <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
2021-05-24 15:22:28 +02:00
2021-05-07 00:26:34 -07:00
2021-05-14 19:41:32 -07:00
2021-05-16 15:27:44 -07:00
…

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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