Hi Doug,
I tried using the MODULE_DEBUG #define and I ran into some compile
issues. This patch gets things to work and adds an official option /
entry to NOTES for help with other folks debugging kern_module.c
logic. I also added some additional data to assist with determining
causes of failure, as well as remove an impossible == NULL case when
using malloc(.., M_WAITOK).
Thanks!
-Garrett
Index: sys/kern/kern_module.c
===================================================================
--- sys/kern/kern_module.c (revision 223138)
+++ sys/kern/kern_module.c (working copy)
@@ -25,6 +25,7 @@
*/
#include "opt_compat.h"
+#include "opt_global.h"
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
@@ -44,6 +45,15 @@
#include <sys/module.h>
#include <sys/linker.h>
+#ifdef MODULE_DEBUG
+#include <sys/sysctl.h>
+
+int mod_debug = 1;
+
+SYSCTL_INT(_debug, OID_AUTO, module_debug, CTLTYPE_INT|CTLFLAG_RW|CTLFLAG_TUN,
+ &mod_debug, 0, "kernel module events to intercept");
+#endif
+
static MALLOC_DEFINE(M_MODULE, "module", "module data structures");
struct module {
@@ -164,10 +174,6 @@
}
namelen = strlen(data->name) + 1;
newmod = malloc(sizeof(struct module) + namelen, M_MODULE, M_WAITOK);
- if (newmod == NULL) {
- MOD_XUNLOCK;
- return (ENOMEM);
- }
newmod->refs = 1;
newmod->id = nextid++;
newmod->name = (char *)(newmod + 1);
@@ -190,7 +196,7 @@
MOD_XLOCK_ASSERT;
- MOD_DPF(REFS, ("module_reference: before, refs=%d\n", mod->refs));
+ MOD_DPF(REFS, "module_reference: before, refs=%d\n", mod->refs);
mod->refs++;
}
@@ -201,12 +207,17 @@
MOD_XLOCK_ASSERT;
if (mod->refs <= 0)
- panic("module_release: bad reference count");
+ panic("module_release: bad reference count, refs=%d\n",
+ mod->refs);
- MOD_DPF(REFS, ("module_release: before, refs=%d\n", mod->refs));
-
+ MOD_DPF(REFS, "module_release: before, module=%s refs=%d\n",
+ mod->name, mod->refs);
+
mod->refs--;
if (mod->refs == 0) {
+ MOD_DPF(REFS,
+ "module_release: freeing last reference to module: %s\n",
+ mod->name);
TAILQ_REMOVE(&modules, mod, link);
if (mod->file)
TAILQ_REMOVE(&mod->file->modules, mod, flink);
Index: sys/sys/module.h
===================================================================
--- sys/sys/module.h (revision 223138)
+++ sys/sys/module.h (working copy)
@@ -177,18 +177,18 @@
void module_setspecific(module_t, modspecific_t *);
struct linker_file *module_file(module_t);
-#ifdef MOD_DEBUG
+#ifdef MODULE_DEBUG
extern int mod_debug;
#define MOD_DEBUG_REFS 1
-#define MOD_DPF(cat, args) do { \
+#define MOD_DPF(cat, fmt, ...) do { \
if (mod_debug & MOD_DEBUG_##cat) \
- printf(args); \
+ printf(fmt, ##__VA_ARGS__); \
} while (0)
-#else /* !MOD_DEBUG */
+#else /* !MODULE_DEBUG */
-#define MOD_DPF(cat, args)
+#define MOD_DPF(cat, fmt, ...)
#endif
#endif /* _KERNEL */
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