module: Introduce module unload taint tracking

Currently, only the initial module that tainted the kernel is
recorded e.g. when an out-of-tree module is loaded.

The purpose of this patch is to allow the kernel to maintain a record of
each unloaded module that taints the kernel. So, in addition to
displaying a list of linked modules (see print_modules()) e.g. in the
event of a detected bad page, unloaded modules that carried a taint/or
taints are displayed too. A tainted module unload count is maintained.

The number of tracked modules is not fixed. This feature is disabled by
default.

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/kernel/module/internal.h b/kernel/module/internal.h
index 0bdf64c9dfb5..bc5507ab8450 100644
--- a/kernel/module/internal.h
+++ b/kernel/module/internal.h
@@ -145,6 +145,27 @@ static inline bool set_livepatch_module(struct module *mod)
 #endif
 }
 
+#ifdef CONFIG_MODULE_UNLOAD_TAINT_TRACKING
+struct mod_unload_taint {
+	struct list_head list;
+	char name[MODULE_NAME_LEN];
+	unsigned long taints;
+	u64 count;
+};
+
+int try_add_tainted_module(struct module *mod);
+void print_unloaded_tainted_modules(void);
+#else /* !CONFIG_MODULE_UNLOAD_TAINT_TRACKING */
+static inline int try_add_tainted_module(struct module *mod)
+{
+	return 0;
+}
+
+static inline void print_unloaded_tainted_modules(void)
+{
+}
+#endif /* CONFIG_MODULE_UNLOAD_TAINT_TRACKING */
+
 #ifdef CONFIG_MODULE_DECOMPRESS
 int module_decompress(struct load_info *info, const void *buf, size_t size);
 void module_decompress_cleanup(struct load_info *info);