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, 46 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/ppc-memtrace b/Documentation/ABI/testing/ppc-memtrace
new file mode 100644
index 000000000..9606aed33
--- /dev/null
+++ b/Documentation/ABI/testing/ppc-memtrace
@@ -0,0 +1,46 @@
+What:		/sys/kernel/debug/powerpc/memtrace
+Date:		Aug 2017
+KernelVersion:	4.14
+Contact:	linuxppc-dev@lists.ozlabs.org
+Description:	This folder contains the relevant debugfs files for the
+		hardware trace macro to use. CONFIG_PPC64_HARDWARE_TRACING
+		must be set.
+
+What:		/sys/kernel/debug/powerpc/memtrace/enable
+Date:		Aug 2017
+KernelVersion:	4.14
+Contact:	linuxppc-dev@lists.ozlabs.org
+Description:	Write an integer containing the size in bytes of the memory
+		you want removed from each NUMA node to this file - it must be
+		aligned to the memblock size. This amount of RAM will be removed
+		from each NUMA node in the kernel mappings and the following
+		debugfs files will be created. Once memory is successfully
+		removed from each node, the following files are created. To
+		re-add memory to the kernel, echo 0 into this file (it will be
+		automatically onlined).
+
+What:		/sys/kernel/debug/powerpc/memtrace/<node-id>
+Date:		Aug 2017
+KernelVersion:	4.14
+Contact:	linuxppc-dev@lists.ozlabs.org
+Description:	This directory contains information about the removed memory
+		from the specific NUMA node.
+
+What:		/sys/kernel/debug/powerpc/memtrace/<node-id>/size
+Date:		Aug 2017
+KernelVersion:	4.14
+Contact:	linuxppc-dev@lists.ozlabs.org
+Description:	This contains the size of the memory removed from the node.
+
+What:		/sys/kernel/debug/powerpc/memtrace/<node-id>/start
+Date:		Aug 2017
+KernelVersion:	4.14
+Contact:	linuxppc-dev@lists.ozlabs.org
+Description:	This contains the start address of the removed memory.
+
+What:		/sys/kernel/debug/powerpc/memtrace/<node-id>/trace
+Date:		Aug 2017
+KernelVersion:	4.14
+Contact:	linuxppc-dev@lists.ozlabs.org
+Description:	This is where the hardware trace macro will output the trace
+		it generates.