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, 52 insertions, 0 deletions

diff --git a/Documentation/tools/rtla/rtla.rst b/Documentation/tools/rtla/rtla.rst
new file mode 100644
index 000000000..6df1296b8
--- /dev/null
+++ b/Documentation/tools/rtla/rtla.rst
@@ -0,0 +1,52 @@
+=========
+rtla
+=========
+--------------------------------
+Real-time Linux Analysis tool
+--------------------------------
+
+:Manual section: 1
+
+SYNOPSIS
+========
+**rtla** *COMMAND* [*OPTIONS*]
+
+DESCRIPTION
+===========
+The **rtla** is a meta-tool that includes a set of commands that aims to
+analyze the real-time properties of Linux. But instead of testing Linux
+as a black box, **rtla** leverages kernel tracing capabilities to provide
+precise information about the properties and root causes of unexpected
+results.
+
+COMMANDS
+========
+**hwnoise**
+
+        Detect and quantify hardware-related noise.
+
+**osnoise**
+
+        Gives information about the operating system noise (osnoise).
+
+**timerlat**
+
+        Measures the IRQ and thread timer latency.
+
+OPTIONS
+=======
+**-h**, **--help**
+
+        Display the help text.
+
+For other options, see the man page for the corresponding command.
+
+SEE ALSO
+========
+**rtla-hwnoise**\(1), **rtla-osnoise**\(1), **rtla-timerlat**\(1)
+
+AUTHOR
+======
+Daniel Bristot de Oliveira <bristot@kernel.org>
+
+.. include:: common_appendix.txt