Messages in this thread Patch in this message | | | Date | Sun, 27 Jan 2008 01:05:39 +0100 (CET) | From | Stefan Richter <> | Subject | [PATCH] firewire: fix "kobject_add failed for fw* with -EEXIST" |
| |
There is a race between shutdown and creation of devices: fw-core may attempt to add a device with the same name of an already existing device. http://bugzilla.kernel.org/show_bug.cgi?id=9828
Impact of the bug: Happens rarely, forces the user to unplug and replug the new device to get it working.
The fix is to defer the deregistration of the minor number until after device_unregister(). This requires an adjustment of the device lookup function though to prevent the character device from being newly opened during shutdown.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> --- drivers/firewire/fw-device.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
Index: linux/drivers/firewire/fw-device.c =================================================================== --- linux.orig/drivers/firewire/fw-device.c +++ linux/drivers/firewire/fw-device.c @@ -616,6 +616,8 @@ struct fw_device *fw_device_from_devt(de down_read(&idr_rwsem); device = idr_find(&fw_device_idr, MINOR(devt)); + if (fw_device_is_shutdown(device)) + device = NULL; up_read(&idr_rwsem); return device; @@ -627,13 +629,13 @@ static void fw_device_shutdown(struct wo container_of(work, struct fw_device, work.work); int minor = MINOR(device->device.devt); - down_write(&idr_rwsem); - idr_remove(&fw_device_idr, minor); - up_write(&idr_rwsem); - fw_device_cdev_remove(device); device_for_each_child(&device->device, NULL, shutdown_unit); + + down_write(&idr_rwsem); device_unregister(&device->device); + idr_remove(&fw_device_idr, minor); + up_write(&idr_rwsem); } static struct device_type fw_device_type = { -- Stefan Richter -=====-==--- ---= ==-== http://arcgraph.de/sr/
| |