protocol on 'lock entry' insertion and removal:
On insertion:
- 1) set the 'list_op_pending' word to the address of the 'lock word'
+ 1) set the 'list_op_pending' word to the address of the 'lock entry'
to be inserted,
2) acquire the futex lock,
3) add the lock entry, with its thread id (TID) in the bottom 29 bits
4) clear the 'list_op_pending' word.
On removal:
- 1) set the 'list_op_pending' word to the address of the 'lock word'
+ 1) set the 'list_op_pending' word to the address of the 'lock entry'
to be removed,
2) remove the lock entry for this lock from the 'head' list,
2) release the futex lock, and
1) the 'head' pointer or an subsequent linked list pointer
is not a valid address of a user space word
2) the calculated location of the 'lock word' (address plus
- 'offset') is not the valud address of a 32 bit user space
+ 'offset') is not the valid address of a 32 bit user space
word
3) if the list contains more than 1 million (subject to
future kernel configuration changes) elements.