Automated hang detection in Java thread dumps

• US 7,278,057 B2
• Filed: 07/31/2003
• Issued: 10/02/2007
• Est. Priority Date: 07/31/2003
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Patel, Dipak M., Betancourt, Michel, Sahoo, Chintamani
• Primary Examiner(s): Beausoliel; Robert W.
• Assistant Examiner(s): PUENTE, EMERSON C
• Application Number:
  US10/632,062
• Publication Number:
  US 20050028157A1
• Time in Patent Office: 1,524 Days
• Field of Search: 714/38
• US Class Current: 714/38.11
• 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; and

a user interface that allows a user to specify criteria, wherein the tool excludes threads that do not meet the criteria from being identified on the user interface as deadlocked threads even though the threads were identified as being deadlocked threads pursuant to the thread dump analysis.

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

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

4. 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; and

receiving, by a user interface, user specified criteria from a user, wherein identified deadlock threads that do not meet the criteria are filtered such that they are not presented to the user by the user interface even though the threads that do not meet the criteria were identified as being deadlocked threads pursuant to the thread dump analysis.

5. The method of claim 4, wherein filtered threads are excluded from identification as threads in a self wait condition.

6. The method of claim 4, wherein the tool analyzes a thread dump file in offline mode.

7. The method of claim 4, wherein a matrix is populated to identify threads owning resources and threads waiting on resources, and wherein the matrix is used to identify threads in a circular wait condition.

8. The method of claim 4, wherein the step of analyzing the thread dump to automatically identify threads in a deadlock condition includes the steps of:

(a) identifying, in the thread dump, a locked object that is already in use by a thread;

(b) identifying threads that own resources the thread that has locked the locked object;

(c) identifying each waiting thread that is waiting on the locked object; and

(d) comparing the results from steps (b) and (c), and then repeating steps (a)-(c) for each locked object in the thread dump, to identify the threads in the circular wait condition and the self wait condition.