linux-kernel - [PATCH] soc: qcom: icc-bwmon: Fix refcount imbalance seen during bwmon

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Date: Thu, 13 Jun 2024 22:15:06 +0530
From: Sibi Sankar <quic_sibis@...cinc.com>
To: <andersson@...nel.org>, <konrad.dybcio@...aro.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <thara.gopinath@...il.com>
CC: <linux-kernel@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        <quic_rgottimu@...cinc.com>, <quic_kshivnan@...cinc.com>,
        <quic_sibis@...cinc.com>, <abel.vesa@...aro.org>
Subject: [PATCH] soc: qcom: icc-bwmon: Fix refcount imbalance seen during bwmon_remove

The following warning is seen during bwmon_remove due to refcount
imbalance, fix this by releasing the OPPs after use.

Logs:
WARNING: at drivers/opp/core.c:1640 _opp_table_kref_release+0x150/0x158
Hardware name: Qualcomm Technologies, Inc. X1E80100 CRD (DT)
...
Call trace:
_opp_table_kref_release+0x150/0x158
dev_pm_opp_remove_table+0x100/0x1b4
devm_pm_opp_of_table_release+0x10/0x1c
devm_action_release+0x14/0x20
devres_release_all+0xa4/0x104
device_unbind_cleanup+0x18/0x60
device_release_driver_internal+0x1ec/0x228
driver_detach+0x50/0x98
bus_remove_driver+0x6c/0xbc
driver_unregister+0x30/0x60
platform_driver_unregister+0x14/0x20
bwmon_driver_exit+0x18/0x524 [icc_bwmon]
__arm64_sys_delete_module+0x184/0x264
invoke_syscall+0x48/0x118
el0_svc_common.constprop.0+0xc8/0xe8
do_el0_svc+0x20/0x2c
el0_svc+0x34/0xdc
el0t_64_sync_handler+0x13c/0x158
el0t_64_sync+0x190/0x194
--[ end trace 0000000000000000 ]---

Fixes: 0276f69f13e2 ("soc: qcom: icc-bwmon: Set default thresholds dynamically")
Fixes: b9c2ae6cac40 ("soc: qcom: icc-bwmon: Add bandwidth monitoring driver")
Signed-off-by: Sibi Sankar <quic_sibis@...cinc.com>
---
 drivers/soc/qcom/icc-bwmon.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/qcom/icc-bwmon.c b/drivers/soc/qcom/icc-bwmon.c
index fb323b3364db..ecddb60bd665 100644
--- a/drivers/soc/qcom/icc-bwmon.c
+++ b/drivers/soc/qcom/icc-bwmon.c
@@ -565,7 +565,7 @@ static void bwmon_start(struct icc_bwmon *bwmon)
 	int window;
 
 	/* No need to check for errors, as this must have succeeded before. */
-	dev_pm_opp_find_bw_ceil(bwmon->dev, &bw_low, 0);
+	dev_pm_opp_put(dev_pm_opp_find_bw_ceil(bwmon->dev, &bw_low, 0));
 
 	bwmon_clear_counters(bwmon, true);
 
@@ -772,11 +772,13 @@ static int bwmon_probe(struct platform_device *pdev)
 	opp = dev_pm_opp_find_bw_floor(dev, &bwmon->max_bw_kbps, 0);
 	if (IS_ERR(opp))
 		return dev_err_probe(dev, PTR_ERR(opp), "failed to find max peak bandwidth\n");
+	dev_pm_opp_put(opp);
 
 	bwmon->min_bw_kbps = 0;
 	opp = dev_pm_opp_find_bw_ceil(dev, &bwmon->min_bw_kbps, 0);
 	if (IS_ERR(opp))
 		return dev_err_probe(dev, PTR_ERR(opp), "failed to find min peak bandwidth\n");
+	dev_pm_opp_put(opp);
 
 	bwmon->dev = dev;
 
-- 
2.34.1