[PATCH][BUG]kallsyms_lookup_name should return the text addres On architectures like IA64, kallsyms_lookup_name(name) returns the actual text address corresponding to the "name" and sometimes returns address of the function descriptor, the behavior is not consistent. The bug is kallsyms_lookup_name() -> module_kallsyms_lookup_name(mod, name) search the name in the given module and returns the address when name is matched. This address very well could be the address of 'U' type which is different address than 't' type. Example: Here is the output of cat /proc/kallsyms when we have test1.ko using the my_test_reentrant_export_function. ----------------------------------------------------------------- a00000020008c090 U my_test_reentrant_export_function [test1] a00000020008c0a0 r __ksymtab_my_test_reentrant_export_function [mon_dummy] a00000020008c0b0 r __kstrtab_my_test_reentrant_export_function [mon_dummy] a00000020008c0d8 r __kcrctab_my_test_reentrant_export_function [mon_dummy] 00000000a356bab8 a __crc_my_test_reentrant_export_function [mon_dummy] a00000020008c000 T my_test_reentrant_export_function [mon_dummy] --------------------------------------------------------------- When we have test1.ko loaded, kallsyms_lookup_name(my_test_reentrant_export_function) returns 0xa00000020008c090 which is a function descriptor address and when test1.ko is removed kallsyms_lookup_name(my_test_reentrant_export_function) returns 0xa00000020008c000 which is the actual text address The current patch check for 't' type(text type) and always returns text address. With this below fix, kallsyms_lookup_name(name) always returns consistent text address. Signed-off-by: Anil S Keshavamurthy ------------------------------------------------------------------- kernel/module.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) Index: linux-2.6.15-mm1/kernel/module.c =================================================================== --- linux-2.6.15-mm1.orig/kernel/module.c +++ linux-2.6.15-mm1/kernel/module.c @@ -2085,13 +2085,14 @@ struct module *module_get_kallsym(unsign up(&module_mutex); return NULL; } - +/* Return the text address corresponding to this name */ static unsigned long mod_find_symname(struct module *mod, const char *name) { unsigned int i; for (i = 0; i < mod->num_symtab; i++) - if (strcmp(name, mod->strtab+mod->symtab[i].st_name) == 0) + if ((strcmp(name, mod->strtab+mod->symtab[i].st_name) == 0) && + (mod->symtab[i].st_info == 't')) return mod->symtab[i].st_value; return 0; } --