Re: [PATCH v2] static_key: Improve uninizialized key warning
From: Steven Rostedt
Date: Wed Oct 18 2017 - 12:07:09 EST
On Wed, 18 Oct 2017 17:24:28 +0200
Borislav Petkov <bp@xxxxxxxxx> 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@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>
Reviewed-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
-- Steve
> 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);
> }