[PATCH v2] static_key: Improve uninizialized key warning

From: Borislav Petkov
Date: Wed Oct 18 2017 - 11:24:43 EST


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@xxxxxxx>

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@xxxxxxx>
Cc: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
Cc: Jason Baron <jbaron@xxxxxxxxxx>
Cc: "Peter Zijlstra (Intel)" <peterz@xxxxxxxxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
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.

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