2df6948428
In the code path
__usb_hcd_giveback_urb()
-> wdm_in_callback()
-> service_outstanding_interrupt()
The function service_outstanding_interrupt() will unconditionally enable
interrupts during unlock and invoke usb_submit_urb() with GFP_KERNEL.
If the HCD completes in BH (like ehci does) then the context remains
atomic due local_bh_disable() and enabling interrupts does not change
this.
Defer the error case handling to a workqueue as suggested by Oliver
Neukum. In case of an error the worker performs the read out and wakes
the user.
Fixes: c1da59dad0 ("cdc-wdm: Clear read pipeline in case of error")
Cc: Robert Foss <robert.foss@collabora.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.