GNU Classpath: Use pthread_sigmask() to set the signal mask - #22
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classlibInitialiseSignalMask() uses sigprocmask(), whose effect in multithreaded processes is unspecified by POSIX. This is OK when the function is called by the initial thread, as at that point the VM is effectively still single-threaded, but not when it is called for externally created threads that attach through JNI. Fix this by using pthread_sigmask() instead. This was originally generic code: commit 089a6a0 ("OpenJDK: Do not block signals") made signal mask initialisation classlib-specific, retaining the previously shared code for GNU Classpath, while the new OpenJDK implementation already used pthread_sigmask() correctly. Signed-off-by: Guillermo Rodríguez <grodriguez@ingelabs.com>
phvega
approved these changes
Aug 21, 2026
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classlibInitialiseSignalMask() uses sigprocmask(), whose effect in multithreaded processes is unspecified by POSIX. This is OK when the function is called by the initial thread, as at that point the VM is effectively still single-threaded, but not when it is called for externally created threads that attach through JNI.
Fix this by using pthread_sigmask() instead.
This was originally generic code: commit 089a6a0 ("OpenJDK: Do not block signals") made signal mask initialisation classlib-specific, retaining the previously shared code for GNU Classpath, while the new OpenJDK implementation already used pthread_sigmask() correctly.