locking/static_keys: Improve uninitialized key warning

Right now it says:

  static_key_disable_cpuslocked used before call to jump_label_init
  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 0 at kernel/jump_label.c:161 static_key_disable_cpuslocked+0x68/0x70
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper Not tainted 4.14.0-rc5+ #1
  Hardware name: SGI.COM C2112-4GP3/X10DRT-P-Series, BIOS 2.0a 05/09/2016
  task: ffffffff81c0e480 task.stack: ffffffff81c00000
  RIP: 0010:static_key_disable_cpuslocked+0x68/0x70
  RSP: 0000:ffffffff81c03ef0 EFLAGS: 00010096 ORIG_RAX: 0000000000000000
  RAX: 0000000000000041 RBX: ffffffff81c32680 RCX: ffffffff81c5cbf8
  RDX: 0000000000000001 RSI: 0000000000000092 RDI: 0000000000000002
  RBP: ffff88807fffd240 R08: 726f666562206465 R09: 0000000000000136
  R10: 0000000000000000 R11: 696e695f6c656261 R12: ffffffff82158900
  R13: ffffffff8215f760 R14: 0000000000000001 R15: 0000000000000008
  FS:  0000000000000000(0000) GS:ffff883f7f400000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: ffff88807ffff000 CR3: 0000000001c09000 CR4: 00000000000606b0
  Call Trace:
   static_key_disable+0x16/0x20
   start_kernel+0x15a/0x45d
   ? load_ucode_intel_bsp+0x11/0x2d
   secondary_startup_64+0xa5/0xb0
  Code: 48 c7 c7 a0 15 cf 81 e9 47 53 4b 00 48 89 df e8 5f fc ff ff eb e8 48 c7 c6 \
	c0 97 83 81 48 c7 c7 d0 ff a2 81 31 c0 e8 c5 9d f5 ff <0f> ff eb a7 0f ff eb \
	b0 e8 eb a2 4b 00 53 48 89 fb e8 42 0e f0

but it doesn't tell me which key it is. So dump the key's name too:

  static_key_disable_cpuslocked(): static key 'virt_spin_lock_key' used before call to jump_label_init()

And that makes pinpointing which key is causing that a lot easier.

 include/linux/jump_label.h           |   14 +++++++-------
 include/linux/jump_label_ratelimit.h |    6 +++---
 kernel/jump_label.c                  |   14 +++++++-------
 3 files changed, 17 insertions(+), 17 deletions(-)

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20171018152428.ffjgak4o25f7ept6@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/jump_label.h

@@ -81,9 +81,9 @@
 
 extern bool static_key_initialized;
 
-#define STATIC_KEY_CHECK_USE() WARN(!static_key_initialized,		      \
-				    "%s used before call to jump_label_init", \
-				    __func__)
+#define STATIC_KEY_CHECK_USE(key) WARN(!static_key_initialized,		      \
+				    "%s(): static key '%pS' used before call to jump_label_init()", \
+				    __func__, (key))
 
 #ifdef HAVE_JUMP_LABEL
 
@@ -211,13 +211,13 @@ static __always_inline bool static_key_true(struct static_key *key)
 
 static inline void static_key_slow_inc(struct static_key *key)
 {
-	STATIC_KEY_CHECK_USE();
+	STATIC_KEY_CHECK_USE(key);
 	atomic_inc(&key->enabled);
 }
 
 static inline void static_key_slow_dec(struct static_key *key)
 {
-	STATIC_KEY_CHECK_USE();
+	STATIC_KEY_CHECK_USE(key);
 	atomic_dec(&key->enabled);
 }
 
@@ -236,7 +236,7 @@ static inline int jump_label_apply_nops(struct module *mod)
 
 static inline void static_key_enable(struct static_key *key)
 {
-	STATIC_KEY_CHECK_USE();
+	STATIC_KEY_CHECK_USE(key);
 
 	if (atomic_read(&key->enabled) != 0) {
 		WARN_ON_ONCE(atomic_read(&key->enabled) != 1);
@@ -247,7 +247,7 @@ static inline void static_key_enable(struct static_key *key)
 
 static inline void static_key_disable(struct static_key *key)
 {
-	STATIC_KEY_CHECK_USE();
+	STATIC_KEY_CHECK_USE(key);
 
 	if (atomic_read(&key->enabled) != 1) {
 		WARN_ON_ONCE(atomic_read(&key->enabled) != 0);

include/linux/jump_label_ratelimit.h

@@ -24,18 +24,18 @@ struct static_key_deferred {
 };
 static inline void static_key_slow_dec_deferred(struct static_key_deferred *key)
 {
-	STATIC_KEY_CHECK_USE();
+	STATIC_KEY_CHECK_USE(key);
 	static_key_slow_dec(&key->key);
 }
 static inline void static_key_deferred_flush(struct static_key_deferred *key)
 {
-	STATIC_KEY_CHECK_USE();
+	STATIC_KEY_CHECK_USE(key);
 }
 static inline void
 jump_label_rate_limit(struct static_key_deferred *key,
 		unsigned long rl)
 {
-	STATIC_KEY_CHECK_USE();
+	STATIC_KEY_CHECK_USE(key);
 }
 #endif	/* HAVE_JUMP_LABEL */
 #endif	/* _LINUX_JUMP_LABEL_RATELIMIT_H */

kernel/jump_label.c

@@ -83,7 +83,7 @@ static void static_key_slow_inc_cpuslocked(struct static_key *key)
 {
 	int v, v1;
 
-	STATIC_KEY_CHECK_USE();
+	STATIC_KEY_CHECK_USE(key);
 
 	/*
 	 * Careful if we get concurrent static_key_slow_inc() calls;
@@ -128,7 +128,7 @@ EXPORT_SYMBOL_GPL(static_key_slow_inc);
 
 void static_key_enable_cpuslocked(struct static_key *key)
 {
-	STATIC_KEY_CHECK_USE();
+	STATIC_KEY_CHECK_USE(key);
 
 	if (atomic_read(&key->enabled) > 0) {
 		WARN_ON_ONCE(atomic_read(&key->enabled) != 1);
@@ -158,7 +158,7 @@ EXPORT_SYMBOL_GPL(static_key_enable);
 
 void static_key_disable_cpuslocked(struct static_key *key)
 {
-	STATIC_KEY_CHECK_USE();
+	STATIC_KEY_CHECK_USE(key);
 
 	if (atomic_read(&key->enabled) != 1) {
 		WARN_ON_ONCE(atomic_read(&key->enabled) != 0);
@@ -224,21 +224,21 @@ static void jump_label_update_timeout(struct work_struct *work)
 
 void static_key_slow_dec(struct static_key *key)
 {
-	STATIC_KEY_CHECK_USE();
+	STATIC_KEY_CHECK_USE(key);
 	__static_key_slow_dec(key, 0, NULL);
 }
 EXPORT_SYMBOL_GPL(static_key_slow_dec);
 
 void static_key_slow_dec_deferred(struct static_key_deferred *key)
 {
-	STATIC_KEY_CHECK_USE();
+	STATIC_KEY_CHECK_USE(key);
 	__static_key_slow_dec(&key->key, key->timeout, &key->work);
 }
 EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred);
 
 void static_key_deferred_flush(struct static_key_deferred *key)
 {
-	STATIC_KEY_CHECK_USE();
+	STATIC_KEY_CHECK_USE(key);
 	flush_delayed_work(&key->work);
 }
 EXPORT_SYMBOL_GPL(static_key_deferred_flush);
@@ -246,7 +246,7 @@ EXPORT_SYMBOL_GPL(static_key_deferred_flush);
 void jump_label_rate_limit(struct static_key_deferred *key,
 		unsigned long rl)
 {
-	STATIC_KEY_CHECK_USE();
+	STATIC_KEY_CHECK_USE(key);
 	key->timeout = rl;
 	INIT_DELAYED_WORK(&key->work, jump_label_update_timeout);
 }