From: Chen-Yu Tsai <wenst@chromium.org>
To: Lai Jiangshan <jiangshanlai@gmail.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Chen-Yu Tsai" <wenst@chromium.org>,
rcu@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mediatek@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
"AngeloGioacchino Del Regno"
<angelogioacchino.delregno@collabora.com>,
"Nícolas F . R . A . Prado" <nfraprado@collabora.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Subject: [PATCH] notifier: Initialize new struct srcu_usage field
Date: Fri, 26 May 2023 15:35:37 +0800 [thread overview]
Message-ID: <20230526073539.339203-1-wenst@chromium.org> (raw)
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
WARNING: multiple messages have this Message-ID (diff)
From: Chen-Yu Tsai <wenst@chromium.org>
To: Lai Jiangshan <jiangshanlai@gmail.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Chen-Yu Tsai" <wenst@chromium.org>,
rcu@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mediatek@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
"AngeloGioacchino Del Regno"
<angelogioacchino.delregno@collabora.com>,
"Nícolas F . R . A . Prado" <nfraprado@collabora.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Subject: [PATCH] notifier: Initialize new struct srcu_usage field
Date: Fri, 26 May 2023 15:35:37 +0800 [thread overview]
Message-ID: <20230526073539.339203-1-wenst@chromium.org> (raw)
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
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next reply other threads:[~2023-05-26 7:36 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-26 7:35 Chen-Yu Tsai [this message]
2023-05-26 7:35 ` [PATCH] notifier: Initialize new struct srcu_usage field 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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