A partial answer: one of the Hotspot engineers says
"I think the short answer is that chaining requires LD_PRELOAD to
override the signal entry points. Otherwise we [Hotspot] wouldn't see
the calls that change the signal handlers. If the Java command itself
linked against jsig that would work too I think. I believe that's the
only way to solve the problem he is seeing in an automatic fashion.
Depending on how the driver library gets loaded they might be able to
build their own signal handler trampolines to work around it and correct
the signal handlers after it gets loaded."
Regards,
Paul
On 5/8/10 7:31 AM, Michael Bien wrote:
Hello everyone,
i am one of the maintainers of JOGL and wrote JOCL
(http://jogamp.org/) and we are currently facing some signal handling
issues caused by the nvidia and amd drivers.
(I got the hint to post to this list since there is no better alias
for this kind of topics)
e.g. the nvidia OpenCL driver uses at least the following handlers:
Warning: SIGSEGV handler expected:libjvm.so+0x5d8cf0
found:libnvidia-compiler.so+0x1865e0
Warning: SIGILL handler expected:libjvm.so+0x5d8cf0
found:libnvidia-compiler.so+0x1865e0
Warning: SIGFPE handler expected:libjvm.so+0x5d8cf0
found:libnvidia-compiler.so+0x1865e0
Warning: SIGBUS handler expected:libjvm.so+0x5d8cf0
found:libnvidia-compiler.so+0x1865e0
Warning: SIGXFSZ handler expected:libjvm.so+0x5d8cf0
found:libnvidia-compiler.so+0x1865e0
(-Xcheck:jni)
which basically makes the jvm unusable on Linux and leads to
segmentation faults (in the driver, I suppose the driver catches jvm
signals).
LD_PRELOAD
(http://java.sun.com/javase/6/webnotes/trouble/TSG-VM/html/signals.html#gbzbl)
works perfectly but it is not allowed for webstart + applets...
do you have any advice how we could workaround this issue? The perfect
solution would be a "-XX:enableSignalChaining" flag which we could set
via jnlp. Since the webstart JVM is out of process anyway (since u10
or so) this would probably work.
Why isn't signal chaining enabled by default on linux and solaris? It
looks like a good self-defence mechanism for me :)
best regards,
Michael Bien
---
http://michael-bien.com
