[PATCH 5.15.y 2/2] wifi: rtw88: check for PCI upstream bridge existence

[Sasha Levin <sashal@kernel.org>]

From: Fedor Pchelkin <pchelkin@ispras.ru>

[ Upstream commit eb101d2abdcccb514ca4fccd3b278dd8267374f6 ]

pci_upstream_bridge() returns NULL if the device is on a root bus.  If
8821CE is installed in the system with such a PCI topology, the probing
routine will crash.  This has probably been unnoticed as 8821CE is mostly
supplied in laptops where there is a PCI-to-PCI bridge located upstream
from the device.  However the card might be installed on a system with
different configuration.

Check if the bridge does exist for the specific workaround to be applied.

Found by Linux Verification Center (linuxtesting.org) with Svace static
analysis tool.

Fixes: 24f5e38a13b5 ("rtw88: Disable PCIe ASPM while doing NAPI poll on 8821CE")
Cc: stable@vger.kernel.org
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20260220094730.49791-1-pchelkin@ispras.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/realtek/rtw88/pci.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtw88/pci.c b/drivers/net/wireless/realtek/rtw88/pci.c
index 0d1b1dfab8a2c..fa302d5e7839d 100644
--- a/drivers/net/wireless/realtek/rtw88/pci.c
+++ b/drivers/net/wireless/realtek/rtw88/pci.c
@@ -1766,7 +1766,8 @@ int rtw_pci_probe(struct pci_dev *pdev,
 	}
 
 	/* Disable PCIe ASPM L1 while doing NAPI poll for 8821CE */
-	if (rtwdev->chip->id == RTW_CHIP_TYPE_8821C && bridge->vendor == PCI_VENDOR_ID_INTEL)
+	if (rtwdev->chip->id == RTW_CHIP_TYPE_8821C &&
+	    bridge && bridge->vendor == PCI_VENDOR_ID_INTEL)
 		rtwpci->rx_no_aspm = true;
 
 	rtw_pci_phy_cfg(rtwdev);
-- 
2.53.0