Messages in this thread |  | | From | Linus Torvalds <> | Date | Tue, 7 Apr 2020 13:47:42 -0700 | Subject | Re: [GIT PULL] Please pull proc and exec work for 5.7-rc1 |
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On Tue, Apr 7, 2020 at 1:29 PM Bernd Edlinger <bernd.edlinger@hotmail.de> wrote: > > Maybe, actually I considered this, but I was anxious that making something > that is so far not killable suddenly killable might break other things.
I don't think it can.
Basically, if you have a execve() and a setprocattr() racing, one or the other starts first.
And if the execve() started first, then the setprocattr() thread would get killed by the execve(), and there's no serialization. So you might as well just say "it got killed before it even started to wait".
So semantically, having a killable wait is basically exactly the same as losing the race - which wasn't ordered to begin with.
It's not like anybody will see the return value - the thread that would have gotten the value got killed.
So doing
if (down_writel_killable(&credlock)) return -EINTR;
may *look* like it's new semantics, but it isn't really. That EINTR error isn't visible to anybody, and everything looks absolutely identical to "execve() in the other thread started earlier and killed the thread even before it got to the system call".
Linus
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