From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
To: Chen-Yu Tsai <wenst@chromium.org>,
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: rcu@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mediatek@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
"Nícolas F . R . A . Prado" <nfraprado@collabora.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: [PATCH] notifier: Initialize new struct srcu_usage field
Date: Fri, 26 May 2023 10:45:32 +0200 [thread overview]
Message-ID: <23366389-1be5-92ef-7728-ce639d46a0b0@collabora.com> (raw)
In-Reply-To: <20230526073539.339203-1-wenst@chromium.org>
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>
WARNING: multiple messages have this Message-ID (diff)
From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
To: Chen-Yu Tsai <wenst@chromium.org>,
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: rcu@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mediatek@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
"Nícolas F . R . A . Prado" <nfraprado@collabora.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: [PATCH] notifier: Initialize new struct srcu_usage field
Date: Fri, 26 May 2023 10:45:32 +0200 [thread overview]
Message-ID: <23366389-1be5-92ef-7728-ce639d46a0b0@collabora.com> (raw)
In-Reply-To: <20230526073539.339203-1-wenst@chromium.org>
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>
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next prev parent reply other threads:[~2023-05-26 8:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
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 [this message]
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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