• Johan Hovold's avatar
    USB: usb_wwan: fix handling of missing bulk endpoints · bd73bd88
    Johan Hovold authored
    Fix regression introduced by commit 8e493ca1 ("USB: usb_wwan: fix
    bulk-urb allocation") by making sure to require both bulk-in and out
    endpoints during port probe.
    
    The original option driver (which usb_wwan is based on) was written
    under the assumption that either endpoint could be missing, but
    evidently this cannot have been tested properly. Specifically, it would
    handle opening a device without bulk-in (but would blow up during resume
    which was implemented later), but not a missing bulk-out in write()
    (although it is handled in some places such as write_room()).
    
    Fortunately (?), the driver also got the test for missing endpoints
    wrong so the urbs were in fact always allocated, although they would be
    initialised using the wrong endpoint address (0) and any submission of
    such an urb would fail.
    
    The commit mentioned above fixed the test for missing endpoints but
    thereby exposed the other bugs which would now generate null-pointer
    exceptions rather than failed urb submissions.
    
    The regression was introduced in v3.7, but the offending commit was also
    marked for stable.
    Reported-by: default avatarRafał Miłecki <zajec5@gmail.com>
    Cc: stable <stable@vger.kernel.org>
    Signed-off-by: default avatarJohan Hovold <jhovold@gmail.com>
    Tested-by: default avatarRafał Miłecki <zajec5@gmail.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    bd73bd88
usb_wwan.c 17.4 KB