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, 199 insertions, 0 deletions

diff --git a/Documentation/netlink/specs/rt-addr.yaml b/Documentation/netlink/specs/rt-addr.yaml
new file mode 100644
index 000000000..0ecbd24c8
--- /dev/null
+++ b/Documentation/netlink/specs/rt-addr.yaml
@@ -0,0 +1,199 @@
+# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+---
+name: rt-addr
+protocol: netlink-raw
+uapi-header: linux/rtnetlink.h
+protonum: 0
+
+doc: >-
+  Address configuration over rtnetlink.
+
+definitions:
+  -
+    name: ifaddrmsg
+    type: struct
+    members:
+      -
+        name: ifa-family
+        type: u8
+      -
+        name: ifa-prefixlen
+        type: u8
+      -
+        name: ifa-flags
+        type: u8
+        enum: ifa-flags
+        enum-as-flags: true
+      -
+        name: ifa-scope
+        type: u8
+      -
+        name: ifa-index
+        type: u32
+  -
+    name: ifa-cacheinfo
+    type: struct
+    members:
+      -
+        name: ifa-prefered
+        type: u32
+      -
+        name: ifa-valid
+        type: u32
+      -
+        name: cstamp
+        type: u32
+      -
+        name: tstamp
+        type: u32
+
+  -
+    name: ifa-flags
+    type: flags
+    name-prefix: ifa-f-
+    enum-name:
+    entries:
+      -
+        name: secondary
+      -
+        name: nodad
+      -
+        name: optimistic
+      -
+        name: dadfailed
+      -
+        name: homeaddress
+      -
+        name: deprecated
+      -
+        name: tentative
+      -
+        name: permanent
+      -
+        name: managetempaddr
+      -
+        name: noprefixroute
+      -
+        name: mcautojoin
+      -
+        name: stable-privacy
+
+attribute-sets:
+  -
+    name: addr-attrs
+    name-prefix: ifa-
+    attributes:
+      -
+        name: address
+        type: binary
+        display-hint: ipv4-or-v6
+      -
+        name: local
+        type: binary
+        display-hint: ipv4-or-v6
+      -
+        name: label
+        type: string
+      -
+        name: broadcast
+        type: u32
+        byte-order: big-endian
+        display-hint: ipv4
+      -
+        name: anycast
+        type: binary
+      -
+        name: cacheinfo
+        type: binary
+        struct: ifa-cacheinfo
+      -
+        name: multicast
+        type: binary
+      -
+        name: flags
+        type: u32
+        enum: ifa-flags
+        enum-as-flags: true
+      -
+        name: rt-priority
+        type: u32
+      -
+        name: target-netnsid
+        type: binary
+      -
+        name: proto
+        type: u8
+      -
+        name: mc-users
+        type: u32
+
+
+operations:
+  fixed-header: ifaddrmsg
+  enum-model: directional
+  name-prefix: rtm-
+  list:
+    -
+      name: newaddr
+      doc: Add new address
+      attribute-set: addr-attrs
+      do:
+        request:
+          value: 20
+          attributes: &ifaddr-all
+            - address
+            - label
+            - local
+            - cacheinfo
+    -
+      name: deladdr
+      doc: Remove address
+      attribute-set: addr-attrs
+      do:
+        request:
+          value: 21
+          attributes:
+            - address
+            - local
+    -
+      name: getaddr
+      doc: Dump address information.
+      attribute-set: addr-attrs
+      dump:
+        request:
+          value: 22
+          attributes: []
+        reply:
+          value: 20
+          attributes: *ifaddr-all
+    -
+      name: getmulticast
+      doc: Get / dump IPv4/IPv6 multicast addresses.
+      attribute-set: addr-attrs
+      fixed-header: ifaddrmsg
+      do:
+        request:
+          value: 58
+          attributes: []
+        reply:
+          value: 58
+          attributes: &mcaddr-attrs
+            - multicast
+            - mc-users
+            - cacheinfo
+      dump:
+        request:
+          value: 58
+          attributes: []
+        reply:
+          value: 58
+          attributes: *mcaddr-attrs
+
+mcast-groups:
+  list:
+    -
+      name: rtnlgrp-ipv4-ifaddr
+      value: 5
+    -
+      name: rtnlgrp-ipv6-ifaddr
+      value: 9