On 12/10, Masami Hiramatsu wrote: > > (2013/12/09 15:20), Namhyung Kim wrote: > > From: Oleg Nesterov <[email protected]> > > > > uprobe_trace_print() and uprobe_perf_print() need to pass the additional > > info to call_fetch() methods, currently there is no simple way to do this. > > > > current->utask looks like a natural place to hold this info, but we need > > to allocate it before handler_chain(). > > > > This is a bit unfortunate, perhaps we will find a better solution later, > > but this is simnple and should work right now. > > Hmm, when this will happen?
Perhaps never. Perhaps it will stay forever and we remove get_utask() from pre_ssout() (it is not needed after this patch). However I still think we can cleanup this. And to remind, we need to clean the usage of utask->vaddr in trace_uprobe.c anyway. We can either try to find another place to pass the info, or we can create a helper(s) for the tracing handlers to access (and populate if NULL) utask->handler_data. Note that this (probably) also makes sense because we can unexport "struct uprobe_task" (but this needs a couple of off-topic cleanups). We will see. Lets do the minimal change which can work right now, Namhyung has enough more serious problems ;) > and isn't it better to increment > miss-hit counter of the uprobe? What do you mean? This is not miss-hit and ->utask == NULL is quite normal. For example, on ppc it can be always NULL because ppc likely emulates the probed insn. Or did you mean that if get_utask() fails we should report this somehow? Well, GFP_KERNEL should "never" fail and even if it fails we will restart the same insn and retry the allocation. Or did I miss your point completely ? Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
