[PATCH 6.18.y] PCI: imx6: Avoid dereferencing a NULL clock name

[Sasha Levin <sashal@kernel.org>]

From: Rudi Heitbaum <rudi@heitbaum.com>

[ Upstream commit e60d0d4dfddfac3058753a1c2255251401c92dad ]

of_clk_bulk_get() leaves 'clk_bulk_data->id' as NULL for every clock that
has no matching entry in "clock-names", which is legal: a node may list
more "clocks" phandles than it names. Both scans of the bulk array
dereference that id unconditionally, so such a node oopses during probe.

The loop in imx_pcie_probe() has been wrong since it was written. The
loop in imx_setup_phy_mpll() was not: it read a fixed clks[] whose ids
came from the driver's own clk_names[] and were never NULL, and only
became wrong when the driver moved to the bulk array.

Check 'clk_bulk_data->id' before dereferencing it in both.

Fixes: f6a1fdfc78e2 ("PCI: imx6: Use devm_clk_bulk_get_all() to fetch clocks")
Fixes: d8574ce57d76 ("PCI: imx6: Add external reference clock input mode support")
Signed-off-by: Rudi Heitbaum <rudi@heitbaum.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/am8iBwJSEhYhWTqk@6cfee64030a6/
Link: https://patch.msgid.link/aqfqE4OLhnN4a1lW@b65e9c1eb12f
[ sashal: Omitted the extref clock-name guard because the corresponding scan is absent. ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pci/controller/dwc/pci-imx6.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index de09cc2a63112..4235f1fb7b337 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -540,7 +540,7 @@ static int imx_setup_phy_mpll(struct imx_pcie *imx_pcie)
 		return 0;
 
 	for (i = 0; i < imx_pcie->num_clks; i++)
-		if (strncmp(clks[i].id, "pcie_phy", 8) == 0)
+		if (clks[i].id && strncmp(clks[i].id, "pcie_phy", 8) == 0)
 			phy_rate = clk_get_rate(clks[i].clk);
 
 	switch (phy_rate) {
-- 
2.53.0