x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 56 insertions, 0 deletions

diff --git a/drivers/hwspinlock/Kconfig b/drivers/hwspinlock/Kconfig
new file mode 100644
index 000000000..d84e00084
--- /dev/null
+++ b/drivers/hwspinlock/Kconfig
@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Generic HWSPINLOCK framework
+#
+
+menuconfig HWSPINLOCK
+	bool "Hardware Spinlock drivers"
+
+if HWSPINLOCK
+
+config HWSPINLOCK_OMAP
+	tristate "OMAP Hardware Spinlock device"
+	depends on ARCH_OMAP4 || SOC_OMAP5 || SOC_DRA7XX || SOC_AM33XX || SOC_AM43XX || ARCH_K3 || COMPILE_TEST
+	help
+	  Say y here to support the OMAP Hardware Spinlock device (firstly
+	  introduced in OMAP4).
+
+	  If unsure, say N.
+
+config HWSPINLOCK_QCOM
+	tristate "Qualcomm Hardware Spinlock device"
+	depends on ARCH_QCOM || COMPILE_TEST
+	select MFD_SYSCON
+	help
+	  Say y here to support the Qualcomm Hardware Mutex functionality, which
+	  provides a synchronisation mechanism for the various processors on
+	  the SoC.
+
+	  If unsure, say N.
+
+config HWSPINLOCK_SPRD
+	tristate "SPRD Hardware Spinlock device"
+	depends on ARCH_SPRD || COMPILE_TEST
+	help
+	  Say y here to support the SPRD Hardware Spinlock device.
+
+	  If unsure, say N.
+
+config HWSPINLOCK_STM32
+	tristate "STM32 Hardware Spinlock device"
+	depends on MACH_STM32MP157 || COMPILE_TEST
+	help
+	  Say y here to support the STM32 Hardware Spinlock device.
+
+	  If unsure, say N.
+
+config HWSPINLOCK_SUN6I
+	tristate "SUN6I Hardware Spinlock device"
+	depends on ARCH_SUNXI || COMPILE_TEST
+	help
+	  Say y here to support the SUN6I Hardware Spinlock device which can be
+	  found in most of the sun6i compatible Allwinner SoCs.
+
+	  If unsure, say N.
+
+endif # HWSPINLOCK