[PATCH 2/2] module: Show the last unloaded module's taint flag(s)

From: Aaron Tomlin
Date: Mon Jun 27 2022 - 12:41:14 EST


For diagnostic purposes, this patch, in addition to keeping a record/or
track of the last known unloaded module, we now will include the
module's taint flag(s) too e.g: " [last unloaded: fpga_mgr_mod(OE)]"

Signed-off-by: Aaron Tomlin <atomlin@xxxxxxxxxx>
---
kernel/module/main.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/kernel/module/main.c b/kernel/module/main.c
index dcb83cf18d84..0ca6fd38b903 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -524,7 +524,12 @@ static struct module_attribute modinfo_##field = { \
MODINFO_ATTR(version);
MODINFO_ATTR(srcversion);

-static char last_unloaded_module[MODULE_NAME_LEN+1];
+/*
+ * Maximum number of characters written by module_flags()
+ * without a module's state information.
+ */
+#define LAST_UNLOADED_MODULE_NAME_LEN (MODULE_NAME_LEN + MODULE_FLAGS_BUF_SIZE - 2 + 1)
+static char last_unloaded_module[LAST_UNLOADED_MODULE_NAME_LEN];

#ifdef CONFIG_MODULE_UNLOAD

@@ -694,6 +699,7 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
{
struct module *mod;
char name[MODULE_NAME_LEN];
+ char buf[LAST_UNLOADED_MODULE_NAME_LEN];
int ret, forced = 0;

if (!capable(CAP_SYS_MODULE) || modules_disabled)
@@ -753,8 +759,8 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user,

async_synchronize_full();

- /* Store the name of the last unloaded module for diagnostic purposes */
strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));
+ strcat(last_unloaded_module, module_flags(mod, buf, false));

free_module(mod);
/* someone could wait for the module in add_unformed_module() */
--
2.34.3