Messages in this thread | | | Date | Mon, 14 Dec 2015 14:40:59 -0700 | Subject | Re: [PATCH] Fix int1 recursion with unregistered breakpoints | From | Jeff Merkey <> |
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On 12/14/15, H. Peter Anvin <hpa@zytor.com> wrote: > On 12/14/15 13:03, Jeff Merkey wrote: >> Please consider the attached patch. >> >> I have reviewed all the code that touches this patch and have >> determined it will function and support all of the software that >> depends on this handler properly. I have compiled and tested this >> patch with a test harness that tests the robustness of the linux >> breakpoint API and handlers in the following ways: >> >> 1. Setting multiple conditional breakpoints through >> arch_install_hw_breakpoint API across four processors to test the rate >> at which the interface can handle breakpoint exceptions >> >> 2. Setting unregistered breakpoints to test the handlers robustness >> in dealing with error handling conditions and errant or spurious >> hardware conditions and to simulate actual "lazy debug register >> switching" (which does not work BTW) with null bp handlers to test the >> robustness of the handlers. >> >> 3. Clearing and setting breakpoints across multiple processors then >> triggering concurrent exceptions in both interrupt and process >> contexts. >> >> This patch improves robustness in several ways in the linux kernel: >> >> 1. Corrects bug in handling unregistered breakpoints. >> >> 2. Provides hardware check of dr7 to determine source of breakpoint >> if OS cannot ascertain the int1 source from its own state and >> variables. >> >> 3. Actually allows "lazy debug register switching" to function, which >> until recently has apparently never been actually seen on live >> hardware or actually tested. >> > > This is all fine and good, but you are missing one of the most important > parts of a patch: a patch description, describing in detail the problem > that it solves and why. This description needs to be comprehensible not > just for people already initiated but for someone doing code archaeology > a decade from now. > > Thanks, > > -hpa > > >
Yes sir, I'll get that added right away.
Jeff
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