On Fri, Jan 25, 2013 at 11:44:14AM -0500, Steven Rostedt wrote: > [ I got an error with linux-arm-ker...@list.infradead.org and had to > remove from CC ]
Blame Arnd :) > > On Fri, 2013-01-25 at 16:26 +0000, Dave Martin wrote: > > > However, if the purpose if making return_address() notrace is just to > > prevent infinite recursion, where finite recursion is safe, then it > > feels fixable as described above. > > > > Steven, do you know whether such an approach might be safe? > > > > I rewrote the function trace recursion code (see linux-next). The > function tracer wont recurse on itself. If the return_address() is only > used by callbacks and not directly by the mcount(ftrace_caller), then > after the first trace, ftrace wont let recursion of the callback. IOW, > callbacks of ftrace don't need to worry about re-entrancy at the same > context level (but do for different contexts, ie. normal, irq, softirq > and NMI). > > (commit edc15cafcbfa3d73f819cae99885a2e35e4cbce5 in linux-next and > friends) Cool. Are you aware of return_address being used elsewhere? Currently I'm not aware of anything else which uses it, and grep is not finding any calls outside ftrace.h that I can see. Cheers ---Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
