Re: [PATCH v6 modules-next 1/2] module: Overwrite st_size instead of st_info

From: Jessica Yu
Date: Fri Dec 14 2018 - 15:59:33 EST


+++ Vincent Whitchurch [14/12/18 17:05 +0100]:
st_info is currently overwritten after relocation and used to store the
elf_type(). However, we're going to need it fix kallsyms on ARM's
Thumb-2 kernels, so preserve st_info and overwrite the st_size field
instead. st_size is neither used by the module core nor by any
architecture.

Reviewed-by: Miroslav Benes <mbenes@xxxxxxx>
Reviewed-by: Dave Martin <Dave.Martin@xxxxxxx>
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>

Applied both. (Thanks for rebasing!)

Thanks,

Jessica

---
v6: Add Miroslav Benes' Reviewed-by
v5: Add Dave Martin's Reviewed-by
v4: Split out to separate patch. Use st_size instead of st_other.
v1-v3: See PATCH 2/2

kernel/module.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 1b5edf78694c..b36ff8a3d562 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2684,7 +2684,7 @@ static void add_kallsyms(struct module *mod, const struct load_info *info)

/* Set types up while we still have access to sections. */
for (i = 0; i < mod->kallsyms->num_symtab; i++)
- mod->kallsyms->symtab[i].st_info
+ mod->kallsyms->symtab[i].st_size
= elf_type(&mod->kallsyms->symtab[i], info);

/* Now populate the cut down core kallsyms for after init. */
@@ -4070,7 +4070,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
kallsyms = rcu_dereference_sched(mod->kallsyms);
if (symnum < kallsyms->num_symtab) {
*value = kallsyms->symtab[symnum].st_value;
- *type = kallsyms->symtab[symnum].st_info;
+ *type = kallsyms->symtab[symnum].st_size;
strlcpy(name, kallsyms_symbol_name(kallsyms, symnum), KSYM_NAME_LEN);
strlcpy(module_name, mod->name, MODULE_NAME_LEN);
*exported = is_exported(name, *value, mod);
--
2.11.0