www.lwn.net/1999/0121/a/mec.html -> lwn.net/1999/0121/a/mec.html
If I put memory-access rule checking in at replay time, I can do better than e-fence, on stock binaries with no recompilation. Hell, I can do better than *Purify* on *stock binaries* and without tangling with their object-code-insertion patents. I have enough information available in the proxy ptrace filter to implement PTRACE_SINGLESTEP_BACKWARDS. They don't even need symbols on their executable, as long as you have an identical executable that does have symbols. Your customer's Apache tips over every two weeks under heavy load? Tell them to run it under the tracer and send you a trace file the next time it tips over. Trace it, run it in real time, then take the trace file back to your high-powered workstation. It's probably the best program I ever *will* write in my entire life. The entire reason I got involved in linux development was to reach a point where I could talk about this technology and get more than two people to download the damn demo and try it out. To get to a place where the gdb maintainers at cygnus would respond to my letters. I suppose it's off-topic, too, because it is a user space program.
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