* [PATCH] notifier: Initialize new struct srcu_usage field
@ 2023-05-26 7:35 ` Chen-Yu Tsai
0 siblings, 0 replies; 6+ messages in thread
From: Chen-Yu Tsai @ 2023-05-26 7:35 UTC (permalink / raw)
To: Lai Jiangshan, Paul E. McKenney, Josh Triplett, Steven Rostedt,
Mathieu Desnoyers
Cc: Chen-Yu Tsai, rcu, linux-kernel, linux-mediatek,
linux-arm-kernel, AngeloGioacchino Del Regno,
Nícolas F . R . A . Prado, Rafael J. Wysocki
In commit 95433f726301 ("srcu: Begin offloading srcu_struct fields to
srcu_update"), a new struct srcu_usage field was added, but was not
properly initialized. This led to a "spinlock bad magic" BUG when
the SRCU notifier was ever used. This was observed in the MediaTek
CCI devfreq driver on next-20230525. Trimmed stack trace as follows:
BUG: spinlock bad magic on CPU#4, swapper/0/1
lock: 0xffffff80ff529ac0, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
Call trace:
spin_bug+0xa4/0xe8
do_raw_spin_lock+0xec/0x120
_raw_spin_lock_irqsave+0x78/0xb8
synchronize_srcu+0x3c/0x168
srcu_notifier_chain_unregister+0x5c/0xa0
cpufreq_unregister_notifier+0x94/0xe0
devfreq_passive_event_handler+0x7c/0x3e0
devfreq_remove_device+0x48/0xe8
Add __SRCU_USAGE_INIT() to SRCU_NOTIFIER_INIT() so that srcu_usage gets
initialized properly.
Fixes: 95433f726301 ("srcu: Begin offloading srcu_struct fields to srcu_update")
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
Also, the original patch subject said "srcu_update", however the data
structure ended up as "srcu_usage". Maybe that could be updated?
include/linux/notifier.h | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index 2aba75145144..86544707236a 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -106,12 +106,22 @@ extern void srcu_init_notifier_head(struct srcu_notifier_head *nh);
#define RAW_NOTIFIER_INIT(name) { \
.head = NULL }
+#ifdef CONFIG_TREE_SRCU
#define SRCU_NOTIFIER_INIT(name, pcpu) \
{ \
.mutex = __MUTEX_INITIALIZER(name.mutex), \
.head = NULL, \
+ .srcuu = __SRCU_USAGE_INIT(name.srcuu), \
.srcu = __SRCU_STRUCT_INIT(name.srcu, name.srcuu, pcpu), \
}
+#else
+#define SRCU_NOTIFIER_INIT(name, pcpu) \
+ { \
+ .mutex = __MUTEX_INITIALIZER(name.mutex), \
+ .head = NULL, \
+ .srcu = __SRCU_STRUCT_INIT(name.srcu, name.srcuu, pcpu), \
+ }
+#endif
#define ATOMIC_NOTIFIER_HEAD(name) \
struct atomic_notifier_head name = \
--
2.41.0.rc0.172.g3f132b7071-goog
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH] notifier: Initialize new struct srcu_usage field
@ 2023-05-26 7:35 ` Chen-Yu Tsai
0 siblings, 0 replies; 6+ messages in thread
From: Chen-Yu Tsai @ 2023-05-26 7:35 UTC (permalink / raw)
To: Lai Jiangshan, Paul E. McKenney, Josh Triplett, Steven Rostedt,
Mathieu Desnoyers
Cc: Chen-Yu Tsai, rcu, linux-kernel, linux-mediatek,
linux-arm-kernel, AngeloGioacchino Del Regno,
Nícolas F . R . A . Prado, Rafael J. Wysocki
In commit 95433f726301 ("srcu: Begin offloading srcu_struct fields to
srcu_update"), a new struct srcu_usage field was added, but was not
properly initialized. This led to a "spinlock bad magic" BUG when
the SRCU notifier was ever used. This was observed in the MediaTek
CCI devfreq driver on next-20230525. Trimmed stack trace as follows:
BUG: spinlock bad magic on CPU#4, swapper/0/1
lock: 0xffffff80ff529ac0, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
Call trace:
spin_bug+0xa4/0xe8
do_raw_spin_lock+0xec/0x120
_raw_spin_lock_irqsave+0x78/0xb8
synchronize_srcu+0x3c/0x168
srcu_notifier_chain_unregister+0x5c/0xa0
cpufreq_unregister_notifier+0x94/0xe0
devfreq_passive_event_handler+0x7c/0x3e0
devfreq_remove_device+0x48/0xe8
Add __SRCU_USAGE_INIT() to SRCU_NOTIFIER_INIT() so that srcu_usage gets
initialized properly.
Fixes: 95433f726301 ("srcu: Begin offloading srcu_struct fields to srcu_update")
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
Also, the original patch subject said "srcu_update", however the data
structure ended up as "srcu_usage". Maybe that could be updated?
include/linux/notifier.h | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index 2aba75145144..86544707236a 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -106,12 +106,22 @@ extern void srcu_init_notifier_head(struct srcu_notifier_head *nh);
#define RAW_NOTIFIER_INIT(name) { \
.head = NULL }
+#ifdef CONFIG_TREE_SRCU
#define SRCU_NOTIFIER_INIT(name, pcpu) \
{ \
.mutex = __MUTEX_INITIALIZER(name.mutex), \
.head = NULL, \
+ .srcuu = __SRCU_USAGE_INIT(name.srcuu), \
.srcu = __SRCU_STRUCT_INIT(name.srcu, name.srcuu, pcpu), \
}
+#else
+#define SRCU_NOTIFIER_INIT(name, pcpu) \
+ { \
+ .mutex = __MUTEX_INITIALIZER(name.mutex), \
+ .head = NULL, \
+ .srcu = __SRCU_STRUCT_INIT(name.srcu, name.srcuu, pcpu), \
+ }
+#endif
#define ATOMIC_NOTIFIER_HEAD(name) \
struct atomic_notifier_head name = \
--
2.41.0.rc0.172.g3f132b7071-goog
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] notifier: Initialize new struct srcu_usage field
2023-05-26 7:35 ` Chen-Yu Tsai
@ 2023-05-26 8:45 ` AngeloGioacchino Del Regno
-1 siblings, 0 replies; 6+ messages in thread
From: AngeloGioacchino Del Regno @ 2023-05-26 8:45 UTC (permalink / raw)
To: Chen-Yu Tsai, Lai Jiangshan, Paul E. McKenney, Josh Triplett,
Steven Rostedt, Mathieu Desnoyers
Cc: rcu, linux-kernel, linux-mediatek, linux-arm-kernel,
Nícolas F . R . A . Prado, Rafael J. Wysocki
Il 26/05/23 09:35, Chen-Yu Tsai ha scritto:
> In commit 95433f726301 ("srcu: Begin offloading srcu_struct fields to
> srcu_update"), a new struct srcu_usage field was added, but was not
> properly initialized. This led to a "spinlock bad magic" BUG when
> the SRCU notifier was ever used. This was observed in the MediaTek
> CCI devfreq driver on next-20230525. Trimmed stack trace as follows:
>
> BUG: spinlock bad magic on CPU#4, swapper/0/1
> lock: 0xffffff80ff529ac0, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
> Call trace:
> spin_bug+0xa4/0xe8
> do_raw_spin_lock+0xec/0x120
> _raw_spin_lock_irqsave+0x78/0xb8
> synchronize_srcu+0x3c/0x168
> srcu_notifier_chain_unregister+0x5c/0xa0
> cpufreq_unregister_notifier+0x94/0xe0
> devfreq_passive_event_handler+0x7c/0x3e0
> devfreq_remove_device+0x48/0xe8
>
> Add __SRCU_USAGE_INIT() to SRCU_NOTIFIER_INIT() so that srcu_usage gets
> initialized properly.
>
> Fixes: 95433f726301 ("srcu: Begin offloading srcu_struct fields to srcu_update")
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] notifier: Initialize new struct srcu_usage field
@ 2023-05-26 8:45 ` AngeloGioacchino Del Regno
0 siblings, 0 replies; 6+ messages in thread
From: AngeloGioacchino Del Regno @ 2023-05-26 8:45 UTC (permalink / raw)
To: Chen-Yu Tsai, Lai Jiangshan, Paul E. McKenney, Josh Triplett,
Steven Rostedt, Mathieu Desnoyers
Cc: rcu, linux-kernel, linux-mediatek, linux-arm-kernel,
Nícolas F . R . A . Prado, Rafael J. Wysocki
Il 26/05/23 09:35, Chen-Yu Tsai ha scritto:
> In commit 95433f726301 ("srcu: Begin offloading srcu_struct fields to
> srcu_update"), a new struct srcu_usage field was added, but was not
> properly initialized. This led to a "spinlock bad magic" BUG when
> the SRCU notifier was ever used. This was observed in the MediaTek
> CCI devfreq driver on next-20230525. Trimmed stack trace as follows:
>
> BUG: spinlock bad magic on CPU#4, swapper/0/1
> lock: 0xffffff80ff529ac0, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
> Call trace:
> spin_bug+0xa4/0xe8
> do_raw_spin_lock+0xec/0x120
> _raw_spin_lock_irqsave+0x78/0xb8
> synchronize_srcu+0x3c/0x168
> srcu_notifier_chain_unregister+0x5c/0xa0
> cpufreq_unregister_notifier+0x94/0xe0
> devfreq_passive_event_handler+0x7c/0x3e0
> devfreq_remove_device+0x48/0xe8
>
> Add __SRCU_USAGE_INIT() to SRCU_NOTIFIER_INIT() so that srcu_usage gets
> initialized properly.
>
> Fixes: 95433f726301 ("srcu: Begin offloading srcu_struct fields to srcu_update")
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] notifier: Initialize new struct srcu_usage field
2023-05-26 7:35 ` Chen-Yu Tsai
@ 2023-05-27 10:27 ` Paul E. McKenney
-1 siblings, 0 replies; 6+ messages in thread
From: Paul E. McKenney @ 2023-05-27 10:27 UTC (permalink / raw)
To: Chen-Yu Tsai
Cc: Lai Jiangshan, Josh Triplett, Steven Rostedt, Mathieu Desnoyers,
rcu, linux-kernel, linux-mediatek, linux-arm-kernel,
AngeloGioacchino Del Regno, Nícolas F . R . A . Prado,
Rafael J. Wysocki
On Fri, May 26, 2023 at 03:35:37PM +0800, Chen-Yu Tsai wrote:
> In commit 95433f726301 ("srcu: Begin offloading srcu_struct fields to
> srcu_update"), a new struct srcu_usage field was added, but was not
> properly initialized. This led to a "spinlock bad magic" BUG when
> the SRCU notifier was ever used. This was observed in the MediaTek
> CCI devfreq driver on next-20230525. Trimmed stack trace as follows:
>
> BUG: spinlock bad magic on CPU#4, swapper/0/1
> lock: 0xffffff80ff529ac0, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
> Call trace:
> spin_bug+0xa4/0xe8
> do_raw_spin_lock+0xec/0x120
> _raw_spin_lock_irqsave+0x78/0xb8
> synchronize_srcu+0x3c/0x168
> srcu_notifier_chain_unregister+0x5c/0xa0
> cpufreq_unregister_notifier+0x94/0xe0
> devfreq_passive_event_handler+0x7c/0x3e0
> devfreq_remove_device+0x48/0xe8
>
> Add __SRCU_USAGE_INIT() to SRCU_NOTIFIER_INIT() so that srcu_usage gets
> initialized properly.
>
> Fixes: 95433f726301 ("srcu: Begin offloading srcu_struct fields to srcu_update")
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Good catch, thank you!
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
> ---
>
> Also, the original patch subject said "srcu_update", however the data
> structure ended up as "srcu_usage". Maybe that could be updated?
>
> include/linux/notifier.h | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/include/linux/notifier.h b/include/linux/notifier.h
> index 2aba75145144..86544707236a 100644
> --- a/include/linux/notifier.h
> +++ b/include/linux/notifier.h
> @@ -106,12 +106,22 @@ extern void srcu_init_notifier_head(struct srcu_notifier_head *nh);
> #define RAW_NOTIFIER_INIT(name) { \
> .head = NULL }
>
> +#ifdef CONFIG_TREE_SRCU
> #define SRCU_NOTIFIER_INIT(name, pcpu) \
> { \
> .mutex = __MUTEX_INITIALIZER(name.mutex), \
> .head = NULL, \
> + .srcuu = __SRCU_USAGE_INIT(name.srcuu), \
> .srcu = __SRCU_STRUCT_INIT(name.srcu, name.srcuu, pcpu), \
> }
> +#else
> +#define SRCU_NOTIFIER_INIT(name, pcpu) \
> + { \
> + .mutex = __MUTEX_INITIALIZER(name.mutex), \
> + .head = NULL, \
> + .srcu = __SRCU_STRUCT_INIT(name.srcu, name.srcuu, pcpu), \
> + }
> +#endif
>
> #define ATOMIC_NOTIFIER_HEAD(name) \
> struct atomic_notifier_head name = \
> --
> 2.41.0.rc0.172.g3f132b7071-goog
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] notifier: Initialize new struct srcu_usage field
@ 2023-05-27 10:27 ` Paul E. McKenney
0 siblings, 0 replies; 6+ messages in thread
From: Paul E. McKenney @ 2023-05-27 10:27 UTC (permalink / raw)
To: Chen-Yu Tsai
Cc: Lai Jiangshan, Josh Triplett, Steven Rostedt, Mathieu Desnoyers,
rcu, linux-kernel, linux-mediatek, linux-arm-kernel,
AngeloGioacchino Del Regno, Nícolas F . R . A . Prado,
Rafael J. Wysocki
On Fri, May 26, 2023 at 03:35:37PM +0800, Chen-Yu Tsai wrote:
> In commit 95433f726301 ("srcu: Begin offloading srcu_struct fields to
> srcu_update"), a new struct srcu_usage field was added, but was not
> properly initialized. This led to a "spinlock bad magic" BUG when
> the SRCU notifier was ever used. This was observed in the MediaTek
> CCI devfreq driver on next-20230525. Trimmed stack trace as follows:
>
> BUG: spinlock bad magic on CPU#4, swapper/0/1
> lock: 0xffffff80ff529ac0, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
> Call trace:
> spin_bug+0xa4/0xe8
> do_raw_spin_lock+0xec/0x120
> _raw_spin_lock_irqsave+0x78/0xb8
> synchronize_srcu+0x3c/0x168
> srcu_notifier_chain_unregister+0x5c/0xa0
> cpufreq_unregister_notifier+0x94/0xe0
> devfreq_passive_event_handler+0x7c/0x3e0
> devfreq_remove_device+0x48/0xe8
>
> Add __SRCU_USAGE_INIT() to SRCU_NOTIFIER_INIT() so that srcu_usage gets
> initialized properly.
>
> Fixes: 95433f726301 ("srcu: Begin offloading srcu_struct fields to srcu_update")
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Good catch, thank you!
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
> ---
>
> Also, the original patch subject said "srcu_update", however the data
> structure ended up as "srcu_usage". Maybe that could be updated?
>
> include/linux/notifier.h | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/include/linux/notifier.h b/include/linux/notifier.h
> index 2aba75145144..86544707236a 100644
> --- a/include/linux/notifier.h
> +++ b/include/linux/notifier.h
> @@ -106,12 +106,22 @@ extern void srcu_init_notifier_head(struct srcu_notifier_head *nh);
> #define RAW_NOTIFIER_INIT(name) { \
> .head = NULL }
>
> +#ifdef CONFIG_TREE_SRCU
> #define SRCU_NOTIFIER_INIT(name, pcpu) \
> { \
> .mutex = __MUTEX_INITIALIZER(name.mutex), \
> .head = NULL, \
> + .srcuu = __SRCU_USAGE_INIT(name.srcuu), \
> .srcu = __SRCU_STRUCT_INIT(name.srcu, name.srcuu, pcpu), \
> }
> +#else
> +#define SRCU_NOTIFIER_INIT(name, pcpu) \
> + { \
> + .mutex = __MUTEX_INITIALIZER(name.mutex), \
> + .head = NULL, \
> + .srcu = __SRCU_STRUCT_INIT(name.srcu, name.srcuu, pcpu), \
> + }
> +#endif
>
> #define ATOMIC_NOTIFIER_HEAD(name) \
> struct atomic_notifier_head name = \
> --
> 2.41.0.rc0.172.g3f132b7071-goog
>
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-05-27 10:28 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2023-05-26 7:35 [PATCH] notifier: Initialize new struct srcu_usage field Chen-Yu Tsai
2023-05-26 7:35 ` Chen-Yu Tsai
2023-05-26 8:45 ` AngeloGioacchino Del Regno
2023-05-26 8:45 ` AngeloGioacchino Del Regno
2023-05-27 10:27 ` Paul E. McKenney
2023-05-27 10:27 ` Paul E. McKenney
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