kunit: Fix race condition in try-catch completion

KUnit's try-catch infrastructure now uses vfork_done, which is always
set to a valid completion when a kthread is created, but which is set to
NULL once the thread terminates. This creates a race condition, where
the kthread exits before we can wait on it.

Keep a copy of vfork_done, which is taken before we wake_up_process()
and so valid, and wait on that instead.

Fixes: 93533996100c ("kunit: Handle test faults")
Reported-by: Linux Kernel Functional Testing <[email protected]>
Closes: https://lore.kernel.org/lkml/[email protected]/
Tested-by: Linux Kernel Functional Testing <[email protected]>
Acked-by: Mickaël Salaün <[email protected]>
Signed-off-by: David Gow <[email protected]>
Reviewed-by: Rae Moar <[email protected]>
Tested-by: Miguel Ojeda <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

0 files changed, 0 insertions, 0 deletions