Automated hang detection in Java thread dumps

• US 20050028157A1
• Filed: 07/31/2003
• Published: 02/03/2005
• Est. Priority Date: 07/31/2003
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Patel, Dipak M., Betancourt, Michel, Sahoo, Chintamani
• Granted Patent: US 7,278,057 B2
• Time in Patent Office: Days
• US Class Current: 718/100
• CPC Class Codes: G06F 11/0715 in a system implementing multitasking multitasking per se G06F9/46
• CPC Class Codes: G06F 11/0751 Error or fault detection not based on redundancy power supply failures G06F1/30; network fault management H04L41/06
• CPC Class Codes: G06F 11/366 using diagnostics G06F11/0703 takes precedence
• CPC Class Codes: G06F 9/524 Deadlock detection or avoidance

Abstract

A system and method for analyzing Java thread deadlocks. A snapshot of threads in a Java Virtual Machine is generated, producing a thread dump file which can be analyzed offline. The thread dump file is optimistically parsed to identify threads which are deadlocked. A user is provided with an interface to select filtering rules for the threads, resulting in a set of filtered threads which are candidates for being in infinite wait conditions.

Claims

1. A system for analyzing thread deadlocks in a Java virtual machine, comprising:

a thread analyzer tool, wherein the tool analyzes a thread dump to automatically identify thread deadlocks;

wherein the tool identifies threads that are in a self wait condition and threads that are in a circular wait condition.

2. The system of claim 1, further comprising a user interface that allows a user to specify criteria, wherein the tool excludes threads that do not meet the criteria from identification as deadlocked threads.

3. The system of claim 1, wherein the tool analyzes a thread dump file in offline mode.

4. The system of claim 1, wherein the tool obtains a thread dump from a running information processing system.

5. A method of analyzing thread deadlocks in a Java virtual machine, comprising the steps of:

obtaining a thread dump of a Java virtual machine;

analyzing the thread dump to automatically identify threads in a deadlock condition;

wherein threads in a circular wait condition and threads in a self wait condition are identified.

6. The method of claim 5, further comprising a user interface that allows a user to specify criteria, wherein threads that do not meet the criteria are filtered.

7. The method of claim 6, wherein filtered threads are excluded from identification as threads in a self wait condition.

8. The method of claim 5, wherein the tool analyzes a thread dump file in offline mode.

9. The method of claim 5, wherein a matrix is populated with threads owning resources and threads waiting on resources, and wherein the matrix is used to identify threads in a circular wait condition.

10. The method of claim 5, wherein the step of analyzing the thread dump to automatically identify threads in a deadlock condition includes the steps of:

(a) identifying threads that own resources;

(b) identifying threads that are waiting on resources;

comparing the results from steps (a) and (b) to identify threads in a circular wait condition.

11. A method of analyzing thread deadlocks in a Java virtual machine (JVM), comprising the steps of:

obtaining a thread dump file;

identifying waiting threads;

identifying locking threads; and

comparing waiting threads and locking threads to identify threads in a self wait condition.

12. The method of claim 11, further comprising the step of comparing waiting threads and locking threads to identify threads in a circular wait condition.

13. The method of claim 11, wherein the step of obtaining a thread dump file comprises obtaining a thread dump from a live JVM.

14. The method of claim 11, wherein the step of obtaining a thread dump file comprises opening an existing thread dump file.

15. The method of claim 14, wherein the existing thread dump file is analyzed in offline mode.

16. The method of claim 11, wherein a user interface allows a user to choose rules, and wherein the rules are used to exclude threads from being identified as in a deadlock condition.

17. A system for analyzing thread deadlocks in a Java virtual machine (JVM), comprising the steps of:

means for obtaining a thread dump file;

means for identifying waiting threads;

means for identifying locking threads; and

means for comparing waiting threads and locking threads to identify threads in a self wait condition.

18. The system of claim 17, further comprising means for comparing waiting threads and locking threads to identify threads in a circular wait condition.

19. The system of claim 17, wherein thread deadlocks are analyzed in offline mode.

20. A computer program product in a computer readable medium for analyzing thread deadlocks in a Java virtual machine, comprising:

first instructions for obtaining a thread dump file;

second instructions for identifying waiting threads;

third instructions for identifying locking threads; and

fourth instructions for comparing waiting threads and locking threads to identify threads in a self wait condition.

21. The computer program product of claim 20, further comprising fifth instructions for comparing waiting threads and locking threads to identify threads in a circular wait condition.

22. The computer program product of claim 20, wherein thread deadlocks are analyzed in offline mode.