On Sun, Aug 29, 2021 at 4:45 PM Bryan Brattlof <hello@xxxxxxxxxxxxxxxxx> wrote: > > Hi Krish > > On this day, August 29, 2021, thus sayeth Krish Jain: > > On Sun, Aug 29, 2021 at 8:17 AM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > > > > On Sun, Aug 29, 2021 at 04:13:43AM +0200, Krish Jain wrote: > > > > On Sat, Aug 28, 2021 at 1:38 AM Bryan Brattlof <hello@xxxxxxxxxxxxxxxxx> wrote: > > > > > As for your patch, I built the driver using: > > > > > > > > > > $ make CCFLAGS=-Werror W=1 M=drivers/staging/android > > > > > > > > > > Which produced the following error: > > > > > > > > > > > > > > > drivers/staging/android/ashmem.c: In function ‘ashmem_mmap’: > > > > > drivers/staging/android/ashmem.c:380:2: warning: ‘static’ is not at beginning of declaration [-Wold-style-declaration] > > > > > 380 | const static struct file_operations vmfile_fops; > > > > > | ^~~~~ > > > > > drivers/staging/android/ashmem.c:431:16: error: assignment of read-only variable ‘vmfile_fops’ > > > > > 431 | vmfile_fops = *vmfile->f_op; > > > > > | ^ > > > > > drivers/staging/android/ashmem.c:432:21: error: assignment of member ‘mmap’ in read-only object > > > > > 432 | vmfile_fops.mmap = ashmem_vmfile_mmap; > > > > > | ^ > > > > > drivers/staging/android/ashmem.c:433:34: error: assignment of member ‘get_unmapped_area’ in read-only object > > > > > 433 | vmfile_fops.get_unmapped_area = > > > > > | ^ > > > > > make[1]: *** [scripts/Makefile.build:271: drivers/staging/android/ashmem.o] Error 1 > > > > > make: *** [Makefile:1851: drivers/staging/android] Error 2 > > > > > > > > > > > > > Hi, this seems very useful and I tried this myself just now. I don't > > > > get any errors that you do though. When I hit enter I just get a new > > > > shell prompt. What am I doing wrong? Probably a silly mistake. I ran > > > > make CCFLAGS=-Werror M=drivers/staging/android/. > > > > > > Are you sure the file is being built at all? You usually have to select > > > the proper configuration option to enable that driver as well. > > > > > > Hi, what option do you mean? I already ran make allmodconfig and sudo > > make modules_install install and then make "CCFLAGS=-Werror W=1 > > M=drivers/staging/android/" and now I do get output but one line > > "WARNING: Symbol version dump "Module.symvers" is missing. Modules may > > not have dependencies or modversions. You may get many unresolved > > symbol warnings." . Then I tried "make CCFLAGS=-Werror V=1 > > M=drivers/staging/android/" and that outputted the following: > > > > Most of the answers you're asking for are going to get vague responses > (if any) on the mailing lists. The idea being (and I agree with) that > giving out the answers will steal your opportunity to explore and learn > the material yourself. > > Yes, it would be faster if we told you the answer, but ultimately, we > would be doing a disservice to you. > > Besides, more times than not we (me especially) don't have the answer. > > With that said, I will give a (generous) hint. :) > Hi. Do I have to build the kernel once before this works? Or can I just build a module directly? Best Regards > > It looks like your having trouble with Kconfig. Have a look at: > > https://www.kernel.org/doc/html/latest/kbuild/makefiles.html > > and: > > https://www.kernel.org/doc/html/latest/kbuild/modules.html > > Also, you shouldn't need to install anything if you're just testing > whether a module builds. Especially when 'sudo' and 'install' are > involved. > > > > > 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."; \ > > > > If I were you I would be asking: > > "What is a Kernel configuration file? and how did I corrupt mine?" > > https://www.kernel.org/doc/html/latest/kbuild/kconfig.html > > > > > echo >&2 ; \ > > /bin/false) > > make -f ./scripts/Makefile.build obj=drivers/staging/android \ > > single-build= \ > > need-builtin=1 need-modorder=1 > > sh ./scripts/modules-check.sh drivers/staging/android/modules.order > > make -f ./scripts/Makefile.modpost > > WARNING: Symbol version dump "Module.symvers" is missing. > > Modules may not have dependencies or modversions. > > You may get many unresolved symbol warnings. > > make -f ./scripts/Makefile.modfinal > > > > "What is Module.symvers?" > > If you're reading the links I gave, you should know this by now. :) > Check out chapter 6 in "Building External Modules" > > > > > I followed this and ran make oldconfig && make prepare but all that is > > outputted is again "WARNING: Symbol version dump "Module.symvers" is > > missing. Modules may not have dependencies or modversions. You may get > > many unresolved symbol warnings." Then I just tried sudo make > > modules_install install again and what was outputted was: > > > > Again, Be *VERY* careful running commands you do not understand. > Especially when the words 'sudo' and 'install' are in the same > command. > > > > > sed: can't read modules.order: No such file or directory > > make[1]: *** [Makefile:1494: __modinst_pre] Error 2 > > make: *** [Makefile:351: __build_one_by_one] Error 2 > > > > "What does modules.order do?" > > https://www.kernel.org/doc/html/latest/kbuild/kbuild.html > > > > > Any ideas? I've been stuck on debugging for hours to no avail. Please > > enlighten me on where I am messing up. > > > > All I can say is the kernels' documentation is the greatest thing to > have when joining the community. The search bar is *fantastic*. > > https://www.kernel.org/doc/html/latest/index.html > > Together with the collective history of ~30 years of developer's > conversations on Linux Kernel Mailing List (LMKL). > > https://lore.kernel.org/lkml/ > > Along with our ability to see the full commit history at any time by: > > $ git grep <regexp> > > In the end, all of the questions you have are in the documentation. I > can't stress enough how appreciative we should be of contributers to > Documentation/ and people like Jonathan Corbet who take the time to > document how all of this stuff works in such a straight forward way. > > Withholding simple answers like this may seem unfair, but the juice is > absolutely worth the squeeze the next time you run into another issue. > > And trust me when I say you *will* run into another issue. We wouldn't > be here if there weren't constant issues to solve. > > We've all been where you're at. Even Greg, he may deny this, but I'm > sure he has been. > > I'm excited to see what you learn. > ~Bryan > > *** > > Just as an aside, for any other lurkers out there: This was the email > that gave me confidence that I could join this community and that > sending a patch, no matter how small, is welcome. > > https://lore.kernel.org/lkml/Pine.LNX.4.58.0412201646220.4112@xxxxxxxxxxxxxxx/ > > The old "grey-beards" here don't bite, no matter how much they and > everyone else say they do. >
