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, 45 insertions, 0 deletions

diff --git a/fs/lockd/netlink.c b/fs/lockd/netlink.c
new file mode 100644
index 000000000..880c42b4f
--- /dev/null
+++ b/fs/lockd/netlink.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/lockd.yaml */
+/* YNL-GEN kernel source */
+/* To regenerate run: tools/net/ynl/ynl-regen.sh */
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include "netlink.h"
+
+#include <uapi/linux/lockd_netlink.h>
+
+/* LOCKD_CMD_SERVER_SET - do */
+static const struct nla_policy lockd_server_set_nl_policy[LOCKD_A_SERVER_UDP_PORT + 1] = {
+	[LOCKD_A_SERVER_GRACETIME] = { .type = NLA_U32, },
+	[LOCKD_A_SERVER_TCP_PORT] = { .type = NLA_U16, },
+	[LOCKD_A_SERVER_UDP_PORT] = { .type = NLA_U16, },
+};
+
+/* Ops table for lockd */
+static const struct genl_split_ops lockd_nl_ops[] = {
+	{
+		.cmd		= LOCKD_CMD_SERVER_SET,
+		.doit		= lockd_nl_server_set_doit,
+		.policy		= lockd_server_set_nl_policy,
+		.maxattr	= LOCKD_A_SERVER_UDP_PORT,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd	= LOCKD_CMD_SERVER_GET,
+		.doit	= lockd_nl_server_get_doit,
+		.flags	= GENL_CMD_CAP_DO,
+	},
+};
+
+struct genl_family lockd_nl_family __ro_after_init = {
+	.name		= LOCKD_FAMILY_NAME,
+	.version	= LOCKD_FAMILY_VERSION,
+	.netnsok	= true,
+	.parallel_ops	= true,
+	.module		= THIS_MODULE,
+	.split_ops	= lockd_nl_ops,
+	.n_split_ops	= ARRAY_SIZE(lockd_nl_ops),
+};