linux-kernel - [PATCH 05/16] coresight: cti: disclaim device only when it's claimed

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Message-Id: <20200916191737.4001561-6-mathieu.poirier@linaro.org>
Date:   Wed, 16 Sep 2020 13:17:26 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     gregkh@...uxfoundation.org
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 05/16] coresight: cti: disclaim device only when it's claimed

From: Tingwei Zhang <tingwei@...eaurora.org>

Coresight_claim_device() is called in cti_starting_cpu() only
when CTI is enabled while coresight_disclaim_device() is called
uncontionally in cti_dying_cpu(). This triggered below WARNING.
Only call disclaim device when CTI device is enabled to fix it.

[   75.989643] WARNING: CPU: 1 PID: 14 at
kernel/drivers/hwtracing/coresight/coresight.c:209
coresight_disclaim_device_unlocked+0x10/0x24
[   75.989697] CPU: 1 PID: 14 Comm: migration/1 Not tainted
5.9.0-rc1-gff1304be0a05-dirty #21
[   75.989709] Hardware name: Thundercomm Dragonboard 845c (DT)
[   75.989737] pstate: 80c00085 (Nzcv daIf +PAN +UAO BTYPE=--)
[   75.989758] pc : coresight_disclaim_device_unlocked+0x10/0x24
[   75.989775] lr : coresight_disclaim_device+0x24/0x38
[   75.989783] sp : ffff800011cd3c90
.
[   75.990018] Call trace:
[   75.990041]  coresight_disclaim_device_unlocked+0x10/0x24
[   75.990066]  cti_dying_cpu+0x34/0x4c
[   75.990101]  cpuhp_invoke_callback+0x84/0x1e0
[   75.990121]  take_cpu_down+0x90/0xe0
[   75.990154]  multi_cpu_stop+0x134/0x160
[   75.990171]  cpu_stopper_thread+0xb0/0x13c
[   75.990196]  smpboot_thread_fn+0x1c4/0x270
[   75.990222]  kthread+0x128/0x154
[   75.990251]  ret_from_fork+0x10/0x18

Fixes: e9b880581d55 ("coresight: cti: Add CPU Hotplug handling to CTI driver")
Signed-off-by: Tingwei Zhang <tingwei@...eaurora.org>
Reviewed-by: Mike Leach <mike.leach@...aro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
---
 drivers/hwtracing/coresight/coresight-cti.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c
index 3ccc703dc940..d6fea6efec71 100644
--- a/drivers/hwtracing/coresight/coresight-cti.c
+++ b/drivers/hwtracing/coresight/coresight-cti.c
@@ -742,7 +742,8 @@ static int cti_dying_cpu(unsigned int cpu)
 
 	spin_lock(&drvdata->spinlock);
 	drvdata->config.hw_powered = false;
-	coresight_disclaim_device(drvdata->base);
+	if (drvdata->config.hw_enabled)
+		coresight_disclaim_device(drvdata->base);
 	spin_unlock(&drvdata->spinlock);
 	return 0;
 }
-- 
2.25.1