• Stephen Boyd's avatar
    rt2x00: Fix lockdep warning in rt2x00lib_probe_dev() · 9acd56d3
    Stephen Boyd authored
    The rt2x00dev->intf_work workqueue is never initialized when a driver is
    probed for a non-existent device (in this case rt2500usb). On such a
    path we call rt2x00lib_remove_dev() to free any resources initialized
    during the probe before we use INIT_WORK to initialize the workqueue.
    This causes lockdep to get confused since the lock used in the workqueue
    hasn't been initialized yet but is now being acquired during
    cancel_work_sync() called by rt2x00lib_remove_dev().
    
    Fix this by initializing the workqueue first before we attempt to probe
    the device. This should make lockdep happy and avoid breaking any
    assumptions about how the library cleans up after a probe fails.
    
    phy0 -> rt2x00lib_probe_dev: Error - Failed to allocate device.
    INFO: trying to register non-static key.
    the code is fine but needs lockdep annotation.
    turning off the locking correctness validator.
    Pid: 2027, comm: modprobe Not tainted 2.6.35-rc5+ #60
    Call Trace:
     [<ffffffff8105fe59>] register_lock_class+0x152/0x31f
     [<ffffffff81344a00>] ? usb_control_msg+0xd5/0x111
     [<ffffffff81061bde>] __lock_acquire+0xce/0xcf4
     [<ffffffff8105f6fd>] ? trace_hardirqs_off+0xd/0xf
     [<ffffffff81492aef>] ?  _raw_spin_unlock_irqrestore+0x33/0x41
     [<ffffffff810628d5>] lock_acquire+0xd1/0xf7
     [<ffffffff8104f037>] ? __cancel_work_timer+0x99/0x17e
     [<ffffffff8104f06e>] __cancel_work_timer+0xd0/0x17e
     [<ffffffff8104f037>] ? __cancel_work_timer+0x99/0x17e
     [<ffffffff8104f136>] cancel_work_sync+0xb/0xd
     [<ffffffffa0096675>] rt2x00lib_remove_dev+0x25/0xb0 [rt2x00lib]
     [<ffffffffa0096bf7>] rt2x00lib_probe_dev+0x380/0x3ed [rt2x00lib]
     [<ffffffff811d78a7>] ? __raw_spin_lock_init+0x31/0x52
     [<ffffffffa00bbd2c>] ? T.676+0xe/0x10 [rt2x00usb]
     [<ffffffffa00bbe4f>] rt2x00usb_probe+0x121/0x15e [rt2x00usb]
     [<ffffffff813468bd>] usb_probe_interface+0x151/0x19e
     [<ffffffff812ea08e>] driver_probe_device+0xa7/0x136
     [<ffffffff812ea167>] __driver_attach+0x4a/0x66
     [<ffffffff812ea11d>] ? __driver_attach+0x0/0x66
     [<ffffffff812e96ca>] bus_for_each_dev+0x54/0x89
     [<ffffffff812e9efd>] driver_attach+0x19/0x1b
     [<ffffffff812e9b64>] bus_add_driver+0xb4/0x204
     [<ffffffff812ea41b>] driver_register+0x98/0x109
     [<ffffffff813465dd>] usb_register_driver+0xb2/0x173
     [<ffffffffa00ca000>] ? rt2500usb_init+0x0/0x20 [rt2500usb]
     [<ffffffffa00ca01e>] rt2500usb_init+0x1e/0x20 [rt2500usb]
     [<ffffffff81000203>] do_one_initcall+0x6d/0x17a
     [<ffffffff8106cae8>] sys_init_module+0x9c/0x1e0
     [<ffffffff8100296b>] system_call_fastpath+0x16/0x1b
    Signed-off-by: default avatarStephen Boyd <bebarino@gmail.com>
    Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
    9acd56d3
rt2x00dev.c 24.3 KB