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, 38 insertions, 0 deletions

diff --git a/arch/alpha/Kconfig.debug b/arch/alpha/Kconfig.debug
new file mode 100644
index 000000000..f85f4281c
--- /dev/null
+++ b/arch/alpha/Kconfig.debug
@@ -0,0 +1,38 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config EARLY_PRINTK
+	bool
+	depends on ALPHA_GENERIC || ALPHA_SRM
+	default y
+
+config ALPHA_LEGACY_START_ADDRESS
+	bool "Legacy kernel start address"
+	depends on ALPHA_GENERIC
+	default n
+	help
+	  The 2.4 kernel changed the kernel start address from 0x310000
+	  to 0x810000 to make room for the Wildfire's larger SRM console.
+	  Recent consoles on Titan and Marvel machines also require the
+	  extra room.
+
+	  If you're using aboot 0.7 or later, the bootloader will examine the
+	  ELF headers to determine where to transfer control. Unfortunately,
+	  most older bootloaders -- APB or MILO -- hardcoded the kernel start
+	  address rather than examining the ELF headers, and the result is a
+	  hard lockup.
+
+	  Say Y if you have a broken bootloader.  Say N if you do not, or if
+	  you wish to run on Wildfire, Titan, or Marvel.
+
+config ALPHA_LEGACY_START_ADDRESS
+	bool
+	depends on !ALPHA_GENERIC && !ALPHA_TITAN && !ALPHA_MARVEL && !ALPHA_WILDFIRE
+	default y
+
+config MATHEMU
+	tristate "Kernel FP software completion" if DEBUG_KERNEL && !SMP
+	default y if !DEBUG_KERNEL || SMP
+	help
+	  This option is required for IEEE compliant floating point arithmetic
+	  on the Alpha. The only time you would ever not say Y is to say M in
+	  order to debug the code. Say Y unless you know what you are doing.