From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20030225 Description of problem: When a USB mouse is unplugged, and nearly at the same time a process like the X server is releasing its input devices (closing the file /dev/input/mice), the kernel may crash, panic, or oops. This happens because of a race between mousedev_release, and mousedev_disconnect, both of which ultimately kfree the same data structure. Version-Release number of selected component (if applicable): kernel-2.6.9-22.EL How reproducible: Sometimes Steps to Reproduce: 1. Ensure that no process currently has the file /dev/input/mice open. (use fuser). 2. Write a small program that simply opens and closes /dev/input/mice. Put this program in a loop. 3. With the above program running, disconnect the USB mouse. This may take a few tries. Actual Results: Eventually, kfree is called twice, and the system panics or crashes. Expected Results: No crash or panic. Additional info: Upstream code is slightly different, but it's not obvious that the race is fixed. Shouldn't be too hard to verify that using the steps outlined in the repro. Note: the deadly race only happens when the _last_ user of /dev/input/mice closes the file. This bug has probably been around for a while, but we managed to close down the X server just at the right time when somebody was unplugging the USB mouse. All the relavant code is in drivers/input/mousedev.c.
Created attachment 148969 [details] Test patch 1 Kimball, care to give this a try?
I want the requestor to decide if this is a problem they want pursuing further. The bug is real, just does not happen often.
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