Detecting software race conditions
Detecting a race condition is disclosed. An indication of a store operation to a memory address is received. An identifier of the memory address is stored. The identifier is used to detect an occurrence of a memory operation that is not associated with a previous ordering operation.
1. A method of detecting a race condition, comprising:
receiving an indication of a store operation to a memory address;
storing an identifier of the memory address; and
using the identifier to detect an occurrence of a memory operation that is not associated with a previous ordering operation, including using the identifier of the memory address to search a global data structure associated with a plurality of processors; wherein:
a search result of the global data structure can be used to identify a private data structure associated with at least one processor; and
detecting the memory operation includes using the identifier of the memory address to search the private data structure.
2. A method as recited in claim 1 , wherein the memory operation includes one or more of the following: a store operation to the memory address, and a load operation from the memory address.
3. A method as recited in claim 1 , wherein using the identifier to detect the memory operation occurrence includes determining that an ordering operation has been omitted.
4. A method as recited in claim 1 , wherein using the identifier to detect the memory operation occurrence includes performing one or more of the following: trapping the memory operation, replacing the memory operation, and running the memory operation in a simulator.
5. A method as recited in claim 1 , wherein the ordering operation includes one or more of the following: a fence operation, a barrier operation, and a compare and swap operation.
6. A method as recited in claim 1 , wherein using the identifier to detect the memory operation occurrence includes displaying or logging information of the memory operation.
7. A method as recited in claim 6 , wherein the information of the memory operation includes one or more of the following: the memory address, an identifier of a processor performing the memory operation, and an identifier of a location within a program.
8. A method as recited in claim 1 , wherein detecting the memory operation occurrence allows a user to view, identify, or correct an undesired race condition caused by the memory operation.
9. A method as recited in claim 1 , further comprising associating and storing with the identifier of the memory address one or more of the following: an identifier of a processor associated with the memory operation, a program counter, an identifier of a location within a program, a stack location, a stack trace, and a function name.
10. A method as recited in claim 1 , wherein using the identifier to detect the memory operation occurrence includes determining that the memory operation occurrence is associated with a different processor from a processor associated with the store operation.
11. A method as recited in claim 1 , wherein the identifier of the memory address includes at least a portion of the memory address.
12. A method as recited in claim 1 , wherein the store operation is associated with a first processor, and the using the identifier to detect the memory operation occurrence includes determining whether a store operation of a second processor has stored to the memory address after a latest ordering operation has been performed.
13. A method as recited in claim 1 , wherein the store operation is associated with a first processor, and the using the identifier to detect the memory operation occurrence includes determining whether a load operation of a second processor has loaded from the memory address after a latest ordering operation has been performed.
14. A method as recited in claim 1 , wherein storing the identifier of the memory address includes storing the identifier in a data structure associated with a single processor.
15. A method as recited in claim 14 , wherein the identifier of the memory address is stored in a data structure associated with a plurality of processors.
16. A method as recited in claim 1 , wherein storing the identifier of the Memory address includes storing the identifier in a data structure associated with a plurality of processors.
17. A method as recited in claim 16 , wherein the data structure includes an unlocked hash table.
18. A method as recited in claim 16 , wherein the identifier of the memory address is stored with a generation identifier that can be used to determine whether the memory operation is performed after the ordering operation.
19. A method as recited in claim 1 , wherein a search result of the global data structure indicates a memory address that is potentially associated with a race condition.
20. A method as recited in claim 1 , wherein using the identifier to detect the memory operation occurrence includes using one or more predetermined criteria to determine the memory operation is not associated with a benign race condition.
21. A method as recited in claim 1 , wherein the ordering operation orders memory operations such that a store operation, if any, of a processor occurring before the ordering operation is visible to other processors before any memory operation occurring after the ordering operation.
22. A method as recited in claim 1 , wherein performing the ordering operation includes removing the stored identifier of the memory address.
23. A method as recited in claim 1 , wherein the performing the ordering operation includes updating a generation reference identifier that can be used to determine whether the memory operation is performed after the ordering operation.
24. A system for detecting a race condition, comprising:
a processor; and
a memory coupled with the processor, wherein the memory is configured to provide the processor with instructions which when executed cause the processor to:
receive an indication of a store operation to a memory address, store an identifier of the memory address, and use the identifier to detect an occurrence of a memory operation that is not associated with a previous ordering operation; wherein:
using the identifier to detect the memory operation occurrence includes using the identifier of the memory address to search a global data structure associated with a plurality of processors;
a search result of the global data structure can be used to identify a private data structure associated with at least one processor; and
detecting the memory operation includes using the identifier of the memory address to search the private data structure.
25. A computer program product for detecting a race condition, the computer program product being embodied in a computer readable medium and comprising computer instructions for:
receiving an indication of a store operation to a memory address;
storing an identifier of the memory address; and
using the identifier to detect an occurrence of a memory operation that is not associated with a previous ordering operation, including using the identifier of the memory address to search a global data structure associated with a plurality of processors; wherein:
a search result of the global data structure can be used to identify a private data structure associated with at least one processor; and
detecting the memory operation includes using the identifier of the memory address to search the private data structure.