[PATCH 1/3] module: Fix missing taint flags for unloaded modules

[Petr Pavlu]

When recording taint flags for an unloaded module, try_add_tainted_module()
can fail to record some of the module's flags if a record for a module with
the same name already exists and the two have at least one flag in common.
This happens because the function uses 'mod_taint->taints & mod->taints' to
determine whether to merge the new module with the existing record. As
a result, the final report may not provide accurate information about the
taint flags of unloaded modules.

Fix the duplicate check by using the stricter equality comparison.

Fixes: 99bd9956551b ("module: Introduce module unload taint tracking")
Signed-off-by: Petr Pavlu <petr.pavlu@xxxxxxxx>
---
 kernel/module/tracking.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/module/tracking.c b/kernel/module/tracking.c
index 9033ff54c4e2..5bcd1c2701f0 100644
--- a/kernel/module/tracking.c
+++ b/kernel/module/tracking.c
@@ -27,7 +27,7 @@ int try_add_tainted_module(struct module *mod)
 	list_for_each_entry_rcu(mod_taint, &unloaded_tainted_modules, list,
 				lockdep_is_held(&module_mutex)) {
 		if (!strcmp(mod_taint->name, mod->name) &&
-		    mod_taint->taints & mod->taints) {
+		    mod_taint->taints == mod->taints) {
 			mod_taint->count++;
 			goto out;
 		}

-- 
2.55.0