On Sun, Aug 29, 2021 at 11:00 PM Bryan Brattlof <hello@xxxxxxxxxxxxxxxxx> wrote: > > On this day, August 29, 2021, thus sayeth Krish Jain: > > Keeping you updated. Small win. The "Symbol version dump > > "Module.symvers" is missing. " error disappeared. Now I still don't > > know why > > > > Whoop! Any win, no matter their size, always feel great. I ran around > the house yesterday after cross compiling DOOM! for an armel chip. It's > that "win" feeling you get that keeps me involved. > > It is important that you find out why though. What is the importance to > having Module.symvers? and why is it a WARNING and not an ERROR? When a module is loaded/used, the values contained in the kernel are compared with similar values in the module; if they are not equal, the kernel refuses to load the module. I don't need it in my case. > What would happen if we didn't have the proper symbols when compiling or > installing this driver? > How and what generates the Module.symvers file when we *do* need it? The kernel would refuse to load the module. > How can we turn this warning off when we don't need it? > > This is covered in chapter "6. Module Versioning" > > https://www.kernel.org/doc/html/latest/kbuild/modules.html > > > > > ERROR: Kernel configuration is invalid."; \ > > echo >&2 " include/generated/autoconf.h or > > include/config/auto.conf are missing.";\ > > echo >&2 " Run 'make oldconfig && make prepare' on kernel src > > to fix it."; \ > > > > > > is still present. > > > > How can I fix this? > > > > Are there any other 'make *config' options we could try? Yes, like main menuconfig. I tried it but it still doesn't work. > What does 'make prepare' even do? Prepares for different architectures etc. > Why do we even need a configuration file? > > https://www.kernel.org/doc/html/latest/kbuild/kconfig.html > > > > > Best Regards > > > > On Sun, Aug 29, 2021 at 8:28 PM Krish Jain <krishjain02939@xxxxxxxxx> wrote: > > > > > > Basically it says "you must have a prebuilt kernel available that > > > contains the configuration and header files used in the build." Since > > > for the staging kernel "make oldconfig" asked me for more > > > configurations apart from my old configuration file (as it reads the > > > existing .config file that was used for an old kernel and prompts the > > > user for options in the current kernel source that are not found in > > > the file) . So I *don't* currently have a prebuilt kernel that > > > contains all the configuration in my staging kernel's .config file. So > > > do I have to build the kernel once before I can just build the module > > > with "make CCFLAGS=-Werror W=1 M=drivers/staging/android" ? > > > > > What do all these other configuration settings turn on and off anyway? > > Do we really need CONFIG_INFINIBAND turned on if we're working in the > drivers/staging tree of the kernel? No, we don't. I removed it. > What would we gain from having a compiled kernel if we want to test a > single staging driver? No need to compile the entire kernel I guess for my use case. But after all this reading :( I still don't get why " sudo make CCFLAGS=-Werror W=1 M=drivers/staging/android/ V=1" worked for you but not for me. I still get the following errors test -e include/generated/autoconf.h -a -e include/config/auto.conf || ( \ echo >&2; \ echo >&2 " ERROR: Kernel configuration is invalid."; \ echo >&2 " include/generated/autoconf.h or include/config/auto.conf are missing.";\ echo >&2 " Run 'make oldconfig && make prepare' on kernel src to fix it."; \ echo >&2 ; \ /bin/false) ..... How can I fix this? > If you found what Module.symvers does, you should know this. > > > > > > > > > > > Again, do not allow others to rob you of learning how to solve these > > > > > issues yourself. I *strongly* encourage you to familiarize yourself with > > > > > the Kernel Build System in the Documentation. > > > > > > > > > > https://www.kernel.org/doc/html/latest/kbuild/modules.html > > > > > > > > > > Specifically the first paragraph of "2. How to Build External Modules" > > > > > > > > > > It may seem like a lot for such a simple issue but it *is* worth it. > > > > > ~Bryan > > > > > > > > > > > > > That section says > > > > > > > > > > > > "To build external modules, *you must have a prebuilt kernel > > > > available* that contains the configuration and header files used in > > > > the build. Also, the kernel must have been built with modules enabled. > > > > If you are using a distribution kernel, there will be a package for > > > > the kernel you are running provided by your distribution. > > > > > > > > An alternative is to use the “make” target “modules_prepare.” This > > > > will make sure the kernel contains the information required. The > > > > target exists solely as a simple way to prepare a kernel source tree > > > > for building external modules. > > > > > > > > NOTE: “modules_prepare” will not build Module.symvers even if > > > > CONFIG_MODVERSIONS is set; therefore, *a full kernel build needs to be > > > > executed to make module versioning work.*" > > > > > > > > So I am just trying to confirm with you whether I have to first build > > > > the kernel with like "make" or not? As you can imagine my hardware > > > > takes *very* long to build a kernel as I did in my last attempt so I > > > > am asking whether it is needed. Hope you understand. > > > > > > I understand. Though I still don't wish to rob you of this opportunity. > > Your ability to come up with these questions and answer them yourself is > what will make you a better programmer and developer. > > Don't get me wrong. Greg knows all too well the garbage I can shovel his > way. It's not about knowing the answer. It about knowing how to find the > answer yourself. > > ~Bryan >
