Parse the build ID of a module when it is inserted and stash it away in 'struct module' in case we print module symbols. This will be used in a future patch to print the module build ID when module functions are in a stack trace.
Note: we only do this if CONFIG_KALLSYMS is enabled, because if it isn't enabled then module names aren't printed for symbolic pointers and thus build IDs aren't printed either. Cc: Jiri Olsa <[email protected]> Cc: Alexei Starovoitov <[email protected]> Cc: Jessica Yu <[email protected]> Cc: Evan Green <[email protected]> Cc: Hsin-Yi Wang <[email protected]> Signed-off-by: Stephen Boyd <[email protected]> --- include/linux/module.h | 4 ++++ kernel/module.c | 20 ++++++++++++++++++++ 2 files changed, 24 insertions(+) diff --git a/include/linux/module.h b/include/linux/module.h index 59f094fa6f74..9d1f6a5240c1 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -11,6 +11,7 @@ #include <linux/list.h> #include <linux/stat.h> +#include <linux/buildid.h> #include <linux/compiler.h> #include <linux/cache.h> #include <linux/kmod.h> @@ -432,6 +433,9 @@ struct module { /* Notes attributes */ struct module_notes_attrs *notes_attrs; + + /* Module build-id */ + char build_id[BUILD_ID_STR_SIZE_MAX]; #endif /* The command line arguments (may be mangled). People like diff --git a/kernel/module.c b/kernel/module.c index 30479355ab85..a7559a0de9d8 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -13,6 +13,7 @@ #include <linux/trace_events.h> #include <linux/init.h> #include <linux/kallsyms.h> +#include <linux/buildid.h> #include <linux/file.h> #include <linux/fs.h> #include <linux/sysfs.h> @@ -2770,6 +2771,20 @@ static void add_kallsyms(struct module *mod, const struct load_info *info) } mod->core_kallsyms.num_symtab = ndst; } + +static void module_init_build_id(struct module *mod, const struct load_info *info) +{ + const Elf_Shdr *sechdr; + unsigned int i; + + for (i = 0; i < info->hdr->e_shnum; i++) { + sechdr = &info->sechdrs[i]; + if (!sect_empty(sechdr) && sechdr->sh_type == SHT_NOTE && + !build_id_parse_buf((void *)sechdr->sh_addr, mod->build_id, + sechdr->sh_size)) + break; + } +} #else static inline void layout_symtab(struct module *mod, struct load_info *info) { @@ -2778,6 +2793,10 @@ static inline void layout_symtab(struct module *mod, struct load_info *info) static void add_kallsyms(struct module *mod, const struct load_info *info) { } + +static void module_init_build_id(struct module *mod, const struct load_info *info) +{ +} #endif /* CONFIG_KALLSYMS */ static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, unsigned int num) @@ -4004,6 +4023,7 @@ static int load_module(struct load_info *info, const char __user *uargs, goto free_arch_cleanup; } + module_init_build_id(mod, info); dynamic_debug_setup(mod, info->debug, info->num_debug); /* Ftrace init must be called in the MODULE_STATE_UNFORMED state */ -- https://chromeos.dev
