Thread (9 messages) 9 messages, 3 authors, 2022-07-06

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

From: Christophe Leroy <hidden>
Date: 2022-06-28 05:54:36
Also in: lkml


Le 27/06/2022 à 18:40, Aaron Tomlin a écrit :
quoted hunk ↗ jump to hunk
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 <redacted>
---
  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));
You replace a bounded string copy by an unbounded strict contat.

Should you use strlcat() instead ?
  
  	free_module(mod);
  	/* someone could wait for the module in add_unformed_module() */
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