On Tue, Apr 19, 2005 at 12:22:46PM -0500, Tony Asleson wrote: > Timur Tabi wrote: > > >Before compiling usesexport.ko, try loading providesexport.ko. The > >warning should go away. > > Looks like loading the providesexport.ko before the compile does not > remove the warning. insmod to provide symbols to a compile? I don't think so. > > When I load the module providesexport.ko I see this in /var/log/messages > > Apr 19 11:08:39 amd kernel: Provider loaded, exported symbol available. > > When I cat /proc/kallsyms I get > > ffffffff8824b080 r __ksymtab_some_exported_symbol [providesexport] > ffffffff8824b090 r __kstrtab_some_exported_symbol [providesexport] > ffffffff8824b0a8 r __kcrctab_some_exported_symbol [providesexport] > ffffffff8824b030 t some_exported_symbol [providesexport] > 000000006fd120ab a __crc_some_exported_symbol [providesexport] OK, so the some_exported_symbol is defined and loaded. The compiler doesn't care about this. > > So the symbol is available, but with the module loaded I still get the > same warning when > compiling the module that depends on the exported symbol. > > make -C /lib/modules/2.6.11-1.14_FC3/build M=/home/tony/learnexport/user > modules > make[1]: Entering directory `/lib/modules/2.6.11-1.14_FC3/build' > CC [M] /home/tony/learnexport/user/user.o > LD [M] /home/tony/learnexport/user/usesexport.o > Building modules, stage 2. > MODPOST > *** Warning: "some_exported_symbol" > [/home/tony/learnexport/user/usesexport.ko] undefined! > CC /home/tony/learnexport/user/usesexport.mod.o > LD [M] /home/tony/learnexport/user/usesexport.ko > make[1]: Leaving directory `/lib/modules/2.6.11-1.14_FC3/build' As someone said earlier in this thread, it appears that you need something like this in usesexport.c: extern int some_exported_symbol; When you insmod providesexport.ko and then usesexport.ko, the appropriate linkages should be made. > > Any other ideas? The 3rd edition of Linux Device Drivers does not cover > this as > does the other 2 other kernel books I have. At least as I haven't found > it in the > books anyway. Do you: EXPORT_SYMBOL (some_exported_symbol); in providesexport.c? As recommended in LDD, read through other modules in /usr/src/linux/drivers. Trying grepping on EXPORT_SYMBOL: grep -r EXPORT /usr/src/linux/drivers Good luck, -- Mike -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
