I was seeing rmmod getting stuck consistently in D state while removing raw1394. Looking at raw1394.c:cleanup_raw1394 - the order of doing things seemed incorrect to me after comparing other places in raw1394.c which do the same thing but with a different order.
bash R running task 0 4319 3884 3900 (NOTLB) rmmod D 0000008428792a16 0 4490 3900 (NOTLB) ffff81001cff9dd8 0000000000000082 0000000000000000 0000000100000000 0000007400000000 ffff8100211c9070 000000000000097b ffff81002c8a2800 ffffffff80397c97 ffff81002b6f9360 Call Trace:<ffffffff80379d25>{__down+421} <ffffffff80133510>{default_wake_function+0} <ffffffff8037cd8c>{__down_failed+53} <ffffffff801c0e40>{generic_delete_inode+0} <ffffffff8029e540>{.text.lock.driver+5} <ffffffff885a8260>{:raw1394:cleanup_raw1394+16} <ffffffff8015eb31>{sys_delete_module+497} <ffffffff8021a692>{__up_write+514} <ffffffff80183efb>{sys_munmap+107} <ffffffff8010ecda>{system_call +126} Attached patch fixes the rmmod raw1394 hang. Tested. Parag
--- drivers/ieee1394/raw1394.c.orig 2005-02-06 14:34:58.000000000 -0500 +++ drivers/ieee1394/raw1394.c 2005-02-06 14:36:18.000000000 -0500 @@ -2758,10 +2758,10 @@ static void __exit cleanup_raw1394(void) { - hpsb_unregister_protocol(&raw1394_driver); cdev_del(&raw1394_cdev); devfs_remove(RAW1394_DEVICE_NAME); hpsb_unregister_highlevel(&raw1394_highlevel); + hpsb_unregister_protocol(&raw1394_driver); } module_init(init_raw1394);