[patch] get_scno should test TCB_INSYSCALL at the beginning

[Roland McGrath]

> testcase is difficult if you don't have access to some zSeries machine.

I do, though not one running any older kernels.

> There would be now two ways to fix this: a) test directly before the old
> s390 code whether the process is actually entering the kernel or leaving
> it or b) test this at the beginning of get_scno

At the moment I'm only going to do the former, because it is a simpler
change to address the manifest problem you are seeing and the current code
(however nutty) does not as yet have demonstrated problems elsewhere.


Thanks,
Roland