From: Rusty Russell Date: Thu, 5 Aug 2010 18:59:08 +0000 (-0600) Subject: module: fix crash in get_ksymbol() when oopsing in module init X-Git-Tag: firefly_0821_release~9833^2~1284^2~7 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=511ca6ae43fbe0a7c9e0b50ad275f7ef24ef3b58;p=firefly-linux-kernel-4.4.55.git module: fix crash in get_ksymbol() when oopsing in module init Andrew had the sole pleasure of tickling this bug in linux-next; when we set up "info->strtab" it's pointing into the temporary copy of the module. For most uses that is fine, but kallsyms keeps a pointer around during module load (inside mod->strtab). If we oops for some reason inside a module's init function, kallsyms will use the mod->strtab pointer into the now-freed temporary module copy. (Later oopses work fine: after init we overwrite mod->strtab to point to a compacted core-only strtab). Reported-by: Andrew "Grumpy" Morton Signed-off-by: Rusty "Buggy" Russell Tested-by: Andrew "Happy" Morton Signed-off-by: Rusty Russell --- diff --git a/kernel/module.c b/kernel/module.c index 79c4d6f69dd7..60cdd0459eac 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2045,7 +2045,8 @@ static void add_kallsyms(struct module *mod, struct load_info *info, mod->symtab = (void *)symsec->sh_addr; mod->num_symtab = symsec->sh_size / sizeof(Elf_Sym); - mod->strtab = info->strtab; + /* Make sure we get permanent strtab: don't use info->strtab. */ + mod->strtab = (void *)info->sechdrs[info->index.str].sh_addr; /* Set types up while we still have access to sections. */ for (i = 0; i < mod->num_symtab; i++)