Messages in this thread Patch in this message | | | From | Jordi Pujol <> | Subject | Checking versions of the symbols in modules | Date | Tue, 5 Aug 2008 16:24:52 +0200 |
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Hello,
summary: In a kernel already compiled, we install new modules, some of that depend of the others. after charging the first module the next one can not find the symbols that uses from the first.
Kernel version: Linux version 2.6.26.1-686-jp2 (root@pcjordi) (gcc version 4.3.1 (Debian 4.3.1-2) ) #1 SMP PREEMPT Tue Aug 5 11:34:33 CEST 2008
Full description: In a kernel already compiled, we install new modules, some of them depending from the others. In this case the modules are lzma and squashfs-lzma after charging the module lzma we verify in /proc/kallsyms that the symbols have been exported and correctly noted. When we charge the module squashfs that depends on the symbols of sqlzma, the kernel responds: no symbol version for sqlzma_init Unknown symbol sqlzma_init no symbol version for sqlzma_un Unknown symbol sqlzma_un no symbol version for sqlzma_fin Unknown symbol sqlzma_fin
Keywords: modules, symbols
workaround: my first solution was to compile a kernel with MODULE_FORCE_LOADING enabled, and forcing modprobe to do that. That works,
the solution, inspecting the module.c source, can be appreciated differences with the version 2.6.25 in the routine check_version, so that previously has returned correct when the version for a symbol was not found, but in this routine, version 2.6.26 returns error. Works well after modifying some lines of module.c
Attached is the patch to module.c
P.D. if the source of that modules is needed, lzma is from the sid repository of Debian, and squashfs-lzma is my own develop, I can provide the Debian package for it,
Thanks for that good kernel,
Jordi Pujol --- linux-2.6.26.1-old/kernel/module.c 2008-08-02 00:58:24.000000000 +0200 +++ linux-2.6.26.1/kernel/module.c 2008-08-05 14:48:13.000000000 +0200 @@ -936,9 +936,11 @@ goto bad_version; } + /* Not in module's version table. OK, but that taints the kernel. */ printk(KERN_WARNING "%s: no symbol version for %s\n", mod->name, symname); - return 0; + add_taint_module(mod, TAINT_FORCED_MODULE); + return 1; bad_version: printk("%s: disagrees about version of symbol %s\n", | |