On 01/26, Andi Kleen wrote: > > > Simple example. Try to debug/strace strace ot gdb itself. Not trivial, > > you can't attach to strace's tracees. Recently I spent 2 days trying to > > understand why strace -f hangs. I was able to attach to strace, but > > I wasn't able to see what its tracees do. > > But what would the semantics be inside the tracees even if you could? In this particular case, all I need was something like "gdb -p" to attach to the tracee, see the backtrace and detach. > > And, it was not possible to even trace strace until it hangs, with > > ptrace the tracee (strace) must stop to report the event and this > > shadowed the race. > > "Shadowing the race" was the second surname of strace I thought anyways @) > Basically if you care about races never use strace in the first place. Yes. And utrace doesn't require the tracee to be stopped to report the event ;) Yes, yes, utrace can't "fix" strace in this sense automatically, but still. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
