Don't invoke shutdown signal handler until JVM init completes #18085
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babsingh
commented
Sep 6, 2023
| if (J9_ARE_ANY_BITS_SET(vm->runtimeFlags, J9_RUNTIME_EXIT_STARTED)) { | ||
| shutdownStarted = TRUE; | ||
| /* Don't invoke handler if JVM hasn't initialized or JVM exit has started. */ | ||
| issueReadBarrier(); |
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Signal handlers should not incorporate lock operations since they are not signal-safe. I have replaced the lock with a read barrier to read the most up-to-date vm->runtimeFlags value.
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Running a personal build to check if there are any side-effects. I will move the PR out of the draft state once the personal build looks good. @gacholio Requesting your review. @pshipton @tajila fyi, this is related to internal issue 148771. |
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The personal build looks good; no side-effects seen. This PR is ready to be reviewed. |
gacholio
approved these changes
Sep 7, 2023
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jenkins test sanity zlinux jdk21 |
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jenkins compile win jdk8 |
JVM init path: J9_CreateJavaVM. JVM exit paths: protectedDestroyJavaVM and exitJavaVM. A segfault or other side-effects can happen if the JVM init and exit paths execute concurrently. The exit path can be taken if a shutdown signal is raised and the shutdown handler is invoked. JVM shutdown signals are SIGINT, SIGTERM and SIGHUP. Preventing invocation of the exit path from the shutdown signal handler until the JVM initialization completes resolves the above side-effects. Related: - eclipse-openj9#17101 - eclipse-openj9#17438 Signed-off-by: Babneet Singh <[email protected]>
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Accidentally pushed into this PR. The impact of the accidental push has been reverted. Old PR builds:
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JVM init path:
J9_CreateJavaVM.JVM exit paths:
protectedDestroyJavaVMandexitJavaVM.A segfault or other side-effects can happen if the JVM init and
exit paths execute concurrently.
The exit path can be taken if a shutdown signal is raised and the
shutdown handler is invoked. JVM shutdown signals are
SIGINT,SIGTERMand
SIGHUP.Preventing invocation of the exit path from the shutdown signal handler
until the JVM initialization completes resolves the above side-effects.
Related: