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From:   Jijie Shao <shaojijie@huawei.com>
To:     <will@kernel.org>, <jonathan.cameron@huawei.com>,
        <mark.rutland@arm.com>, <yangyicong@hisilicon.com>,
        <shaojijie@huawei.com>
CC:     <chenhao418@huawei.com>, <shenjian15@huawei.com>,
        <wangjie125@huawei.com>, <liuyonglong@huawei.com>,
        <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>
Subject: [PATCH drivers/perf: hisi:] drivers/perf: hisi: fix NULL pointer issue when uninstall hns3 pmu driver
Date:   Mon, 9 Oct 2023 18:50:38 +0800
Message-ID: <20231009105038.126040-1-shaojijie@huawei.com>
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From: Hao Chen <chenhao418@huawei.com>

When uninstall hns3 pmu driver, it will call cpuhp_state_remove_instance()
and then callback function hns3_pmu_offline_cpu() is called, it may cause
NULL pointer call trace when other driver is installing or uninstalling
concurrently.

As John Garry's opinion, cpuhp_state_remove_instance() is used for shared
interrupt, and using cpuhp_state_remove_instance_nocalls() is fine for PCIe
or HNS3 pmu.

So, replace cpuhp_state_remove_instance() with
cpuhp_state_remove_instance_nocalls() to fix this problem.

Fixes: 66637ab137b4 ("drivers/perf: hisi: add driver for HNS3 PMU")
Signed-off-by: Hao Chen <chenhao418@huawei.com>
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
---
 drivers/perf/hisilicon/hns3_pmu.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/perf/hisilicon/hns3_pmu.c b/drivers/perf/hisilicon/hns3_pmu.c
index e0457d84af6b..16869bf5bf4c 100644
--- a/drivers/perf/hisilicon/hns3_pmu.c
+++ b/drivers/perf/hisilicon/hns3_pmu.c
@@ -1556,8 +1556,8 @@ static int hns3_pmu_init_pmu(struct pci_dev *pdev, struct hns3_pmu *hns3_pmu)
 	ret = perf_pmu_register(&hns3_pmu->pmu, hns3_pmu->pmu.name, -1);
 	if (ret) {
 		pci_err(pdev, "failed to register perf PMU, ret = %d.\n", ret);
-		cpuhp_state_remove_instance(CPUHP_AP_PERF_ARM_HNS3_PMU_ONLINE,
-					    &hns3_pmu->node);
+		cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_HNS3_PMU_ONLINE,
+						    &hns3_pmu->node);
 	}
 
 	return ret;
@@ -1568,8 +1568,8 @@ static void hns3_pmu_uninit_pmu(struct pci_dev *pdev)
 	struct hns3_pmu *hns3_pmu = pci_get_drvdata(pdev);
 
 	perf_pmu_unregister(&hns3_pmu->pmu);
-	cpuhp_state_remove_instance(CPUHP_AP_PERF_ARM_HNS3_PMU_ONLINE,
-				    &hns3_pmu->node);
+	cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_HNS3_PMU_ONLINE,
+					    &hns3_pmu->node);
 }
 
 static int hns3_pmu_init_dev(struct pci_dev *pdev)
-- 
2.30.0