taint: add explicit flag to show whether lock dep is still OK.

Fix up all callers as they were before, with make one change: an
unsigned module taints the kernel, but doesn't turn off lockdep.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

4 files changed, 31 insertions, 33 deletions

diff --git a/kernel/module.c b/kernel/module.c
index e69a5a6..cc000dd 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -197,9 +197,10 @@ static inline int strong_try_module_get(struct module *mod)
 		return -ENOENT;
 }
 
-static inline void add_taint_module(struct module *mod, unsigned flag)
+static inline void add_taint_module(struct module *mod, unsigned flag,
+				    enum lockdep_ok lockdep_ok)
 {
-	add_taint(flag);
+	add_taint(flag, lockdep_ok);
 	mod->taints |= (1U << flag);
 }
 
@@ -727,7 +728,7 @@ static inline int try_force_unload(unsigned int flags)
 {
 	int ret = (flags & O_TRUNC);
 	if (ret)
-		add_taint(TAINT_FORCED_RMMOD);
+		add_taint(TAINT_FORCED_RMMOD, LOCKDEP_NOW_UNRELIABLE);
 	return ret;
 }
 #else
@@ -1138,7 +1139,7 @@ static int try_to_force_load(struct module *mod, const char *reason)
 	if (!test_taint(TAINT_FORCED_MODULE))
 		printk(KERN_WARNING "%s: %s: kernel tainted.\n",
 		       mod->name, reason);
-	add_taint_module(mod, TAINT_FORCED_MODULE);
+	add_taint_module(mod, TAINT_FORCED_MODULE, LOCKDEP_NOW_UNRELIABLE);
 	return 0;
 #else
 	return -ENOEXEC;
@@ -2147,7 +2148,8 @@ static void set_license(struct module *mod, const char *license)
 		if (!test_taint(TAINT_PROPRIETARY_MODULE))
 			printk(KERN_WARNING "%s: module license '%s' taints "
 				"kernel.\n", mod->name, license);
-		add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
+		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
+				 LOCKDEP_NOW_UNRELIABLE);
 	}
 }
 
@@ -2700,10 +2702,10 @@ static int check_modinfo(struct module *mod, struct load_info *info, int flags)
 	}
 
 	if (!get_modinfo(info, "intree"))
-		add_taint_module(mod, TAINT_OOT_MODULE);
+		add_taint_module(mod, TAINT_OOT_MODULE, LOCKDEP_STILL_OK);
 
 	if (get_modinfo(info, "staging")) {
-		add_taint_module(mod, TAINT_CRAP);
+		add_taint_module(mod, TAINT_CRAP, LOCKDEP_STILL_OK);
 		printk(KERN_WARNING "%s: module is from the staging directory,"
 		       " the quality is unknown, you have been warned.\n",
 		       mod->name);
@@ -2869,15 +2871,17 @@ static int check_module_license_and_versions(struct module *mod)
 	 * using GPL-only symbols it needs.
 	 */
 	if (strcmp(mod->name, "ndiswrapper") == 0)
-		add_taint(TAINT_PROPRIETARY_MODULE);
+		add_taint(TAINT_PROPRIETARY_MODULE, LOCKDEP_NOW_UNRELIABLE);
 
 	/* driverloader was caught wrongly pretending to be under GPL */
 	if (strcmp(mod->name, "driverloader") == 0)
-		add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
+		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
+				 LOCKDEP_NOW_UNRELIABLE);
 
 	/* lve claims to be GPL but upstream won't provide source */
 	if (strcmp(mod->name, "lve") == 0)
-		add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
+		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
+				 LOCKDEP_NOW_UNRELIABLE);
 
 #ifdef CONFIG_MODVERSIONS
 	if ((mod->num_syms && !mod->crcs)
@@ -3197,7 +3201,7 @@ again:
 			    "%s: module verification failed: signature and/or"
 			    " required key missing - tainting kernel\n",
 			    mod->name);
-		add_taint_module(mod, TAINT_FORCED_MODULE);
+		add_taint_module(mod, TAINT_FORCED_MODULE, LOCKDEP_STILL_OK);
 	}
 #endif
 
diff --git a/kernel/panic.c b/kernel/panic.c
index e1b2822..7c57cc9 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -259,26 +259,19 @@ unsigned long get_taint(void)
 	return tainted_mask;
 }
 
-void add_taint(unsigned flag)
+/**
+ * add_taint: add a taint flag if not already set.
+ * @flag: one of the TAINT_* constants.
+ * @lockdep_ok: whether lock debugging is still OK.
+ *
+ * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
+ * some notewortht-but-not-corrupting cases, it can be set to true.
+ */
+void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
 {
-	/*
-	 * Can't trust the integrity of the kernel anymore.
-	 * We don't call directly debug_locks_off() because the issue
-	 * is not necessarily serious enough to set oops_in_progress to 1
-	 * Also we want to keep up lockdep for staging/out-of-tree
-	 * development and post-warning case.
-	 */
-	switch (flag) {
-	case TAINT_CRAP:
-	case TAINT_OOT_MODULE:
-	case TAINT_WARN:
-	case TAINT_FIRMWARE_WORKAROUND:
-		break;
-
-	default:
-		if (__debug_locks_off())
-			printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
-	}
+	if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
+		printk(KERN_WARNING
+		       "Disabling lock debugging due to kernel taint\n");
 
 	set_bit(flag, &tainted_mask);
 }
@@ -421,7 +414,8 @@ static void warn_slowpath_common(const char *file, int line, void *caller,
 	print_modules();
 	dump_stack();
 	print_oops_end_marker();
-	add_taint(taint);
+	/* Just a warning, don't kill lockdep. */
+	add_taint(taint, LOCKDEP_STILL_OK);
 }
 
 void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 257002c..662f3d5 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2785,7 +2785,7 @@ static noinline void __schedule_bug(struct task_struct *prev)
 	if (irqs_disabled())
 		print_irqtrace_events(prev);
 	dump_stack();
-	add_taint(TAINT_WARN);
+	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
 }
 
 /*
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c88878d..f97f9d7 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2006,7 +2006,7 @@ static int proc_taint(struct ctl_table *table, int write,
 		int i;
 		for (i = 0; i < BITS_PER_LONG && tmptaint >> i; i++) {
 			if ((tmptaint >> i) & 1)
-				add_taint(i);
+				add_taint(i, LOCKDEP_STILL_OK);
 		}
 	}