Java fatal error SIGSEGV with no added native code
So after reading the comments, it seems like this is a bug in the JVM that needs to be reported to Oracle. So, I have gone ahead and filed a bug report to Oracle. I'll post updates when I hear back from them.
Thanks to all those who tried the code and found it breaks on your machines as well.
If there is anyone with the ability/inclination to figure out what code in the compiler is causing this error, it would be awesome to hear about it :)
UPDATE: Someone from Oracle responded yesterday, he said he prepared a fix for the bug and also asked to include my code as a regression test :) He didn't explain what the problem was, beyond saying it was in the HotSpot JIT, but he did send me a link with the changes he made, in case anyone is interested: http://cr.openjdk.java.net/~kvn/8046516/webrev/
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jackkamm
Updated on June 03, 2022Comments
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jackkamm almost 2 years
I am getting an error message from the Java compiler that I don't understand. I've tested my code on OSX 10.6, 10.9, and Ubuntu 14.04, with both Java 6 and 7. When I run with the Eclipse debugger or from the interpreter (using -Xint option), everything runs fine. Otherwise, I get the following messages:
Java 1.6:
Invalid memory access of location 0x8 rip=0x1024e9660
Java 1.7:
# # A fatal error has been detected by the Java Runtime Environment: # # SIGSEGV (0xb) at pc=0x000000010f7a8262, pid=20344, tid=18179 # # JRE version: Java(TM) SE Runtime Environment (7.0_60-b19) (build 1.7.0_60-b19) # Java VM: Java HotSpot(TM) 64-Bit Server VM (24.60-b09 mixed mode bsd-amd64 compressed oops) # Problematic frame: # V [libjvm.dylib+0x3a8262] PhaseIdealLoop::idom_no_update(Node*) const+0x12 # # Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again # # If you would like to submit a bug report, please visit: # http://bugreport.sun.com/bugreport/crash.jsp #
There's more error output for Java 7 (that is saved to a file) but unfortunately I can't fit it in the character limit of this post. Sometimes I need to run my code a couple of times for the error to come up, but it appears more often than not.
My test case involves cacheing some computations in logarithmic scale. Specifically, given log(X),log(Y),..., I have a small class that computes log(X+Y+...). And then I cache the result in a HashMap.
Strangely, changing some loop indices seems to make the problem go away. In particular, if I replace
for (int z = 1; z < x+1; z++) { double logSummand = Math.log(z + x + y); toReturn.addLogSummand(logSummand); }
with
for (int z = 0; z < x; z++) { double logSummand = Math.log(1 + z + x + y); toReturn.addLogSummand(logSummand); }
then I don't get the error message and the program runs fine.
My minimal example is below:
import java.util.Arrays; import java.util.HashMap; import java.util.List; import java.util.Map; public class TestLogSum { public static void main(String[] args) { for (int i = 0; i < 6; i++) { for (int n = 2; n < 30; n++) { for (int j = 1; j <= n; j++) { for (int k = 1; k <= j; k++) { System.out.println(computeSum(k, j)); } } } } } private static Map<List<Integer>, Double> cache = new HashMap<List<Integer>, Double>(); public static double computeSum(int x, int y) { List<Integer> key = Arrays.asList(new Integer[] {x, y}); if (!cache.containsKey(key)) { // explicitly creating/updating a double[] array, instead of using the LogSumArray wrapper object, will prevent the error LogSumArray toReturn = new LogSumArray(x); // changing loop indices will prevent the error // in particular, for(z=0; z<x-1; z++), and then using z+1 in place of z, will not produce error // for (int z = 0; z < x; z++) { // double logSummand = Math.log(1 + z + x + y); for (int z = 1; z < x+1; z++) { double logSummand = Math.log(z + x + y); toReturn.addLogSummand(logSummand); } // returning the value here without cacheing it will prevent the segfault cache.put(key, toReturn.retrieveLogSum()); } return cache.get(key); } /* * Given a bunch of logarithms log(X),log(Y),log(Z),... * This class is used to compute the log of the sum, log(X+Y+Z+...) */ private static class LogSumArray { private double[] logSummandArray; private int currSize; private double maxLogSummand; public LogSumArray(int maxEntries) { this.logSummandArray = new double[maxEntries]; this.currSize = 0; this.maxLogSummand = Double.NEGATIVE_INFINITY; } public void addLogSummand(double logSummand) { logSummandArray[currSize] = logSummand; currSize++; // removing this line will prevent the error maxLogSummand = Math.max(maxLogSummand, logSummand); } public double retrieveLogSum() { if (maxLogSummand == Double.NEGATIVE_INFINITY) return Double.NEGATIVE_INFINITY; assert currSize <= logSummandArray.length; double factorSum = 0; for (int i = 0; i < currSize; i++) { factorSum += Math.exp(logSummandArray[i] - maxLogSummand); } return Math.log(factorSum) + maxLogSummand; } } }
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Fabian almost 10 yearsThat is most likely not a bug in your program (simple java programs should never cause a segmentation fault). It might be a bug in your hardware or your jvm implementation. Try a complete memory check and try a different machine.
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Radiodef almost 10 yearsI have only ever encountered this exact error when writing native code (C, C++, etc) through JNI. Are you using native code (not shown in the question) or is it really all Java? As pointed out already, pure Java should never cause a segfault.
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Fabian almost 10 yearsAfter running the code, I also get a segmentation fault with "java version "1.7.0_55" OpenJDK Runtime Environment (IcedTea 2.4.7) (7u55-2.4.7-2) OpenJDK 64-Bit Server VM (build 24.51-b03, mixed mode)".
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jackkamm almost 10 yearsRadiodef, I'm not using any native code, it's all Java. Fabian, thanks for the confirmation that this is happening on your machine/setup as well.
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Augusto almost 10 yearsThis triggers an jvm error on java 1.7.0_51 but not on 1.8.0_05 on windows 7 x64. Have you tried using the flag ` -XX:-PartialPeelLoop` as there are similar errors reported and that flag is supposed to "skip" the problematic compiler code. Search for
PhaseIdealLoop::idom_no_update
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Hot Licks almost 10 yearsI encountered pretty much the same error when playing with a recursive Java program once.
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jackkamm almost 10 years@Augusto, I've tried -XX:-PartialPeelLoop for Java SE 7 on OSX 10.9 and it still breaks. I've also tried flag -XX:-UseLoopPredicate, which doesn't fix this minimal test case, but did seem to prevent the error in another larger project. (sorry for deleting and reposting this comment, I wanted to edit a couple things in it)
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Martijn Courteaux almost 10 yearsI think this should be reported to Oracle. This code does nothing super special, and still, it breaks. Also on my machine.
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