[PATCH] misc/tst-clone3: Fix waiting for exited thread.

[Stefan Liebler]

Hi,

from time to time the test misc/tst-clone3 fails with an timeout.  Then 
futex_wait is blocking.  Usually ctid should be set to zero due to 
CLONE_CHILD_CLEARTID and the futex should be waken up.  But the fail 
occures if the thread has already exited before ctid is set to the 
return value of clone().  Then futex_wait() will block as there will be 
nobody who wakes the futex up again.

This patch initializes ctid to a known value before calling clone and 
the kernel is the only one who updates the value to zero after clone. 
If futex_wait is called then it is either waked up due to the exited 
thread or the futex syscall fails as *ctid_ptr is already zero instead 
of the specified value 1.

Okay to commit?

Bye
Stefan

ChangeLog:

	* sysdeps/unix/sysv/linux/tst-clone3.c (do_test):
	Initialize ctid with a known value and remove update of ctid
	after clone.
	(wait_tid): Adjust arguments and call futex_wait with ctid_val
	as assumed current value of ctid_ptr.
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