On 12/02/2025 06:13, Shruthi . wrote:
We discussed the issue with AIX OS team to get their input as this
issue is happening only in AIX platform. Update from AIX OS dev team:
A thread gets stuck in dup2() while duplicating a file descriptor that
is already being used by two other threads (one for reading, one for
writing). The writer thread does not write or close the FIFO, causing
the reader to wait indefinitely, which blocks dup2(). Also he is
saying that we cannot change OS side as it may break or change its
existing behavior which other existing applications may be depending on.
Can we apply the previously proposed fix at java level(reordering the
|preClose||()| method) while adding an AIX-specific check to ensure it
doesn’t affect other platforms? Or do you have any alternative
suggestions?
if (!tryClose()) {
long th = thread;
if (th != 0) {
if (!AIX.isAIX)
nd.preClose(fd);
NativeThread.signal(th);
if (AIX.isAIX)
nd.preClose(fd);
}
}
Are you sure this really fixes the issue on AIX? It means a reader or
writer may be signalled before the syscall, is the signal missed or are
you saying that it queues up on AIX? If it missed then the close will
block in dup2 as before.
-Alan
