linux-kernel - [PATCH] pci: tegra194: Fix debugfs cleanup for !CONFIG

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Message-Id: <20250405145459.26800-1-18255117159@163.com>
Date: Sat,  5 Apr 2025 22:54:59 +0800
From: Hans Zhang <18255117159@....com>
To: lpieralisi@...nel.org
Cc: manivannan.sadhasivam@...aro.org,
	thierry.reding@...il.com,
	kw@...ux.com,
	robh@...nel.org,
	bhelgaas@...gle.com,
	jonathanh@...dia.com,
	linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-tegra@...r.kernel.org,
	Hans Zhang <18255117159@....com>
Subject: [PATCH] pci: tegra194: Fix debugfs cleanup for !CONFIG_PCIEASPM

When CONFIG_PCIEASPM is disabled, debugfs entries are not created, but
tegra_pcie_dw_remove() and tegra_pcie_dw_shutdown() unconditionally call
debugfs_remove_recursive(), leading to potential NULL pointer operations.

Introduce deinit_debugfs() to wrap debugfs_remove_recursive(), which is
stubbed for !CONFIG_PCIEASPM. Use this function during removal/shutdown to
ensure debugfs cleanup only occurs when entries were initialized.

This prevents kernel warnings and instability when ASPM support is
disabled.

Signed-off-by: Hans Zhang <18255117159@....com>
---
 drivers/pci/controller/dwc/pcie-tegra194.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 5103995cd6c7..d762e733c2d8 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -716,11 +716,20 @@ static void init_debugfs(struct tegra_pcie_dw *pcie)
 	debugfs_create_devm_seqfile(pcie->dev, "aspm_state_cnt", pcie->debugfs,
 				    aspm_state_cnt);
 }
+
+static void deinit_debugfs(struct tegra_pcie_dw *pcie)
+{
+	if (!pcie->debugfs)
+		return;
+
+	debugfs_remove_recursive(pcie->debugfs);
+}
 #else
 static inline void disable_aspm_l12(struct tegra_pcie_dw *pcie) { return; }
 static inline void disable_aspm_l11(struct tegra_pcie_dw *pcie) { return; }
 static inline void init_host_aspm(struct tegra_pcie_dw *pcie) { return; }
 static inline void init_debugfs(struct tegra_pcie_dw *pcie) { return; }
+static inline void deinit_debugfs(struct tegra_pcie_dw *pcie) { return; }
 #endif
 
 static void tegra_pcie_enable_system_interrupts(struct dw_pcie_rp *pp)
@@ -2289,7 +2298,7 @@ static void tegra_pcie_dw_remove(struct platform_device *pdev)
 		if (!pcie->link_state)
 			return;
 
-		debugfs_remove_recursive(pcie->debugfs);
+		deinit_debugfs(pcie->debugfs);
 		tegra_pcie_deinit_controller(pcie);
 		pm_runtime_put_sync(pcie->dev);
 	} else {
@@ -2408,7 +2417,7 @@ static void tegra_pcie_dw_shutdown(struct platform_device *pdev)
 		if (!pcie->link_state)
 			return;
 
-		debugfs_remove_recursive(pcie->debugfs);
+		deinit_debugfs(pcie->debugfs);
 		tegra_pcie_downstream_dev_to_D0(pcie);
 
 		disable_irq(pcie->pci.pp.irq);

base-commit: a8662bcd2ff152bfbc751cab20f33053d74d0963
-- 
2.25.1