On 01/08/2013 06:27 AM, Anton Arapov wrote: > On Sun, Dec 23, 2012 at 04:49:10PM +0100, Oleg Nesterov wrote: >> On 12/22, Oleg Nesterov wrote: >>>> Just change regs->ip before calling ->handler(). >>> >>> Josh, Frank, will it work for you? >> >> Wait, probably I was confused by this patch and 4/6... >> >> To simplify, lets ignore the normal uprobes. Yes I still think that it >> would be better to set "regs->ip = orig_return_vaddr" before calling >> ->handler() and not pass it as an argument. >> >> But, probably uprobe_consumer also needs to know bp_vaddr? IOW, the >> address of the function which we are going to return from? In this case, >> yes, we also need another argument. And prepare_uretprobe/etc should >> be changed to record bp_vaddr passed from handle_swbp(). And >> uretprobe_run_handlers() should pass this bp_vaddr, not orig_return_vaddr. >> >> Or I am confused. >> >> Anton? > > Oleg, you are absolutely right and change the ip before calling the > ->handle is much better then what I 'invented'. > > I'm working on v2 to address this and other issues, will post it soon.
For uprobes, systemtap wants regs->ip to be the real breakpoint address, and for uretprobes we want the original return address. With the utrace-based uprobes we would munge it by modifying regs->ip before continuing with the rest of our handler. If uprobes now wants to prepare regs->ip for us in the same way, I think that's fine. Josh -- 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/
