[PATCH] static_key: Improve uninizialized key warning

[PATCH] static_key: Improve uninizialized key warning

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

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 its address too:

  static_key_disable_cpuslocked, key ffffffff81c32680 used before call to jump_label_init

so that it can be found:

  $ objdump -D vmlinux | grep ffffffff81c32680
  ffffffff81c32680 <virt_spin_lock_key>:
  ffffffff81c32680:       01 00                   add    %eax,(%rax)

The problem is then obvious:

  smp_prepare_boot_cpu() ->
  native_smp_prepare_boot_cpu()->
  native_pv_lock_init()

which disables that key gets called before jump_label_init().

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
---
 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(-)

diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index cd5861651b17..2c070eeaf1f6 100644
--- a/include/linux/jump_label.h
+++ b/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, key %p 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);
diff --git a/include/linux/jump_label_ratelimit.h b/include/linux/jump_label_ratelimit.h
index 23da3af459fe..93086df0a847 100644
--- a/include/linux/jump_label_ratelimit.h
+++ b/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 */
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 0bf2e8f5244a..8ff4ca4665ff 100644
--- a/kernel/jump_label.c
+++ b/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);
 }
-- 
2.13.0

Re: [PATCH] static_key: Improve uninizialized key warning

[Steven Rostedt]

On Wed, 18 Oct 2017 12:39:13 +0200
Borislav Petkov <bp@alien8.de> wrote:

> From: Borislav Petkov <bp@suse.de>
> 
> 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 its address too:
> 
>   static_key_disable_cpuslocked, key ffffffff81c32680 used before call to jump_label_init
> 
> so that it can be found:
> 
>   $ objdump -D vmlinux | grep ffffffff81c32680
>   ffffffff81c32680 <virt_spin_lock_key>:
>   ffffffff81c32680:       01 00                   add    %eax,(%rax)
> 
> The problem is then obvious:
> 
>   smp_prepare_boot_cpu() ->
>   native_smp_prepare_boot_cpu()->
>   native_pv_lock_init()
> 
> which disables that key gets called before jump_label_init().
> 
> Signed-off-by: Borislav Petkov <bp@suse.de>
>


Acked-by: Steven Rostedt <rostedt@goodmis.org>

-- Steve

Re: [PATCH] static_key: Improve uninizialized key warning

[Ingo Molnar]

* Borislav Petkov <bp@alien8.de> wrote:

> but it doesn't tell me which key it is. So dump its address too:
> 
>   static_key_disable_cpuslocked, key ffffffff81c32680 used before call to jump_label_init

Is it possible to print out a symbol instead of an absolute address - does that 
work for data symbols?

Thanks,

	Ingo

Re: [PATCH] static_key: Improve uninizialized key warning

[Steven Rostedt]

On Wed, 18 Oct 2017 15:19:34 +0200
Ingo Molnar <mingo@kernel.org> wrote:

> * Borislav Petkov <bp@alien8.de> wrote:
> 
> > but it doesn't tell me which key it is. So dump its address too:
> > 
> >   static_key_disable_cpuslocked, key ffffffff81c32680 used before call to jump_label_init  
> 
> Is it possible to print out a symbol instead of an absolute address - does that 
> work for data symbols?

It should.

Boris, can you try it with "%pS" ?

-- Steve

[PATCH v2] static_key: Improve uninizialized key warning

[Borislav Petkov]

On Wed, Oct 18, 2017 at 09:27:10AM -0400, Steven Rostedt wrote:
> Boris, can you try it with "%pS" ?

%ps is better, as it doesn't dump offsets:

[    0.000000] static_key_disable_cpuslocked, key virt_spin_lock_key used before call to jump_label_init

Thx.

---
From: Borislav Petkov <bp@suse.de>

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, key virt_spin_lock_key used before call to jump_label_init.

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

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
---
 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(-)

diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index cd5861651b17..dc126d10a00d 100644
--- a/include/linux/jump_label.h
+++ b/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, 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);
diff --git a/include/linux/jump_label_ratelimit.h b/include/linux/jump_label_ratelimit.h
index 23da3af459fe..93086df0a847 100644
--- a/include/linux/jump_label_ratelimit.h
+++ b/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 */
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 0bf2e8f5244a..8ff4ca4665ff 100644
--- a/kernel/jump_label.c
+++ b/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);
 }
-- 
2.13.0

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

Re: [PATCH v2] static_key: Improve uninizialized key warning

[Steven Rostedt]

On Wed, 18 Oct 2017 17:24:28 +0200
Borislav Petkov <bp@alien8.de> wrote:

> On Wed, Oct 18, 2017 at 09:27:10AM -0400, Steven Rostedt wrote:
> > Boris, can you try it with "%pS" ?  
> 
> %ps is better, as it doesn't dump offsets:

Sometimes offsets are helpful even for variables.

But regardless...

> 
> [    0.000000] static_key_disable_cpuslocked, key virt_spin_lock_key used before call to jump_label_init
> 
> Thx.
> 
> ---
> From: Borislav Petkov <bp@suse.de>
> 
> 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, key virt_spin_lock_key used before call to jump_label_init.
> 
> And that makes pinpointing which key is causing that, a lot easier.
> 
> Signed-off-by: Borislav Petkov <bp@suse.de>
> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Juergen Gross <jgross@suse.com>
> Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

-- Steve

> Cc: Jason Baron <jbaron@akamai.com>
> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> ---
>  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(-)
> 
> diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
> index cd5861651b17..dc126d10a00d 100644
> --- a/include/linux/jump_label.h
> +++ b/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, 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);
> diff --git a/include/linux/jump_label_ratelimit.h b/include/linux/jump_label_ratelimit.h
> index 23da3af459fe..93086df0a847 100644
> --- a/include/linux/jump_label_ratelimit.h
> +++ b/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 */
> diff --git a/kernel/jump_label.c b/kernel/jump_label.c
> index 0bf2e8f5244a..8ff4ca4665ff 100644
> --- a/kernel/jump_label.c
> +++ b/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);
>  }

Re: [PATCH v2] static_key: Improve uninizialized key warning

[Steven Rostedt]

On Wed, 18 Oct 2017 12:06:59 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> > Signed-off-by: Borislav Petkov <bp@suse.de>
> > Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
> > Cc: Ingo Molnar <mingo@kernel.org>
> > Cc: Juergen Gross <jgross@suse.com>
> > Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>  
> 
> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> 


Ingo, you may want to fix the typo in the subject "uninitialized".

-- Steve

Re: [PATCH v2] static_key: Improve uninizialized key warning

[Ingo Molnar]

* Steven Rostedt <rostedt@goodmis.org> wrote:

> On Wed, 18 Oct 2017 12:06:59 -0400
> Steven Rostedt <rostedt@goodmis.org> wrote:
> 
> > > Signed-off-by: Borislav Petkov <bp@suse.de>
> > > Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
> > > Cc: Ingo Molnar <mingo@kernel.org>
> > > Cc: Juergen Gross <jgross@suse.com>
> > > Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>  
> > 
> > Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > 
> 
> 
> Ingo, you may want to fix the typo in the subject "uninitialized".

Yeah, I also changed it to %pS to help debug arrays, or cases where somehow a 
non-data symbol ends up being passed to it. Plus I changed the message from:

  static_key_disable_cpuslocked, key virt_spin_lock_key used before call to jump_label_init.

to:

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

to make it all obviously readable. I mean, what if the symbol is named 'key' and 
we'd get confusing printouts like:

  static_key_disable_cpuslocked, key key used before call to jump_label_init.

Plus functions should be referred to with () to disambiguate them from other 
symbol names. Also, proper use of punctuation symbols.

Thanks,

	Ingo

[tip:locking/core] locking/static_keys: Improve uninitialized key warning

[tip-bot for Borislav Petkov]

Commit-ID:  5cdda5117e125e0dbb020425cc55a4c143c6febc
Gitweb:     https://git.kernel.org/tip/5cdda5117e125e0dbb020425cc55a4c143c6febc
Author:     Borislav Petkov <bp@suse.de>
AuthorDate: Wed, 18 Oct 2017 17:24:28 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 19 Oct 2017 07:49:14 +0200

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

diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index cd58616..979a2f2 100644
--- a/include/linux/jump_label.h
+++ b/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);
diff --git a/include/linux/jump_label_ratelimit.h b/include/linux/jump_label_ratelimit.h
index 23da3af..93086df 100644
--- a/include/linux/jump_label_ratelimit.h
+++ b/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 */
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 0bf2e8f5..8ff4ca4 100644
--- a/kernel/jump_label.c
+++ b/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);
 }