Thanks Michael, On Tuesday 22 November 2016 05:03 PM, Michael Ellerman wrote: > Ravi Bangoria <ravi.bango...@linux.vnet.ibm.com> writes: > >> Xmon data-breakpoint feature is broken. >> >> Whenever there is a watchpoint match occurs, hw_breakpoint_handler will >> be called by do_break via notifier chains mechanism. If watchpoint is >> registered by xmon, hw_breakpoint_handler won't find any associated >> perf_event and returns immediately with NOTIFY_STOP. Similarly, do_break >> also returns without notifying to xmon. >> >> Solve this by returning NOTIFY_DONE when hw_breakpoint_handler does not >> find any perf_event associated with matched watchpoint. > .. rather than NOTIFY_STOP, which tells the core code to continue > calling the other breakpoint handlers including the xmon one. > > Right?
Yes. > Also any idea when we broke this? Hmm, not sure exactly. The code is same since it was merged in 2010 when support for hw_breakpoint was added for server processor. -Ravi > cheers >