Messages in this thread | | | From | Roland McGrath <> | Subject | Re: [PATCH 1/1] ptrace: make sure do_wait() won't hang after PTRACE_ATTACH | Date | Thu, 3 Feb 2011 13:36:39 -0800 (PST) |
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IMHO this sort of band-aid does not really help the overall situation. It takes something that is intricate and fiddly and just fiddles it a bit more. Userland will still have to handle older kernels where this behavior is not there. If userland does anything that relies on this new behavior, then it will have to try somehow to figure out which kernel versions have which behavior and adapt, etc.
When the old behaviors are unhelpful like this, I think it is really better to add new mechanisms instead. We can make new mechanisms more clear and straightforward for userland to work with from the beginning. Then the compatibility picture for userland is simply to try a new call or new ptrace request or new option bit or whatever it is. When the kernel supports the new thing, things are easy. When it doesn't, then they cope with life as they have been coping before on old kernels.
I have some ideas about new things to add for this problem area. But we have to think those through carefully and discuss all the details thoroughly with Jan and other folks working on userland debuggers before we write the kernel side.
Thanks, Roland
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