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, 175 insertions, 0 deletions

diff --git a/drivers/dpll/dpll_nl.c b/drivers/dpll/dpll_nl.c
new file mode 100644
index 000000000..b1ba490e7
--- /dev/null
+++ b/drivers/dpll/dpll_nl.c
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/dpll.yaml */
+/* YNL-GEN kernel source */
+/* To regenerate run: tools/net/ynl/ynl-regen.sh */
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include "dpll_nl.h"
+
+#include <uapi/linux/dpll.h>
+
+/* Common nested types */
+const struct nla_policy dpll_pin_parent_device_nl_policy[DPLL_A_PIN_OPERSTATE + 1] = {
+	[DPLL_A_PIN_PARENT_ID] = { .type = NLA_U32, },
+	[DPLL_A_PIN_DIRECTION] = NLA_POLICY_RANGE(NLA_U32, 1, 2),
+	[DPLL_A_PIN_PRIO] = { .type = NLA_U32, },
+	[DPLL_A_PIN_STATE] = NLA_POLICY_RANGE(NLA_U32, 1, 3),
+	[DPLL_A_PIN_OPERSTATE] = NLA_POLICY_RANGE(NLA_U32, 1, 4),
+	[DPLL_A_PIN_PHASE_OFFSET] = { .type = NLA_S64, },
+	[DPLL_A_PIN_FRACTIONAL_FREQUENCY_OFFSET] = { .type = NLA_SINT, },
+	[DPLL_A_PIN_FRACTIONAL_FREQUENCY_OFFSET_PPT] = { .type = NLA_SINT, },
+};
+
+const struct nla_policy dpll_pin_parent_pin_nl_policy[DPLL_A_PIN_STATE + 1] = {
+	[DPLL_A_PIN_PARENT_ID] = { .type = NLA_U32, },
+	[DPLL_A_PIN_STATE] = NLA_POLICY_RANGE(NLA_U32, 1, 3),
+};
+
+const struct nla_policy dpll_reference_sync_nl_policy[DPLL_A_PIN_STATE + 1] = {
+	[DPLL_A_PIN_ID] = { .type = NLA_U32, },
+	[DPLL_A_PIN_STATE] = NLA_POLICY_RANGE(NLA_U32, 1, 3),
+};
+
+/* DPLL_CMD_DEVICE_ID_GET - do */
+static const struct nla_policy dpll_device_id_get_nl_policy[DPLL_A_TYPE + 1] = {
+	[DPLL_A_MODULE_NAME] = { .type = NLA_NUL_STRING, },
+	[DPLL_A_CLOCK_ID] = { .type = NLA_U64, },
+	[DPLL_A_TYPE] = NLA_POLICY_RANGE(NLA_U32, 1, 3),
+};
+
+/* DPLL_CMD_DEVICE_GET - do */
+static const struct nla_policy dpll_device_get_nl_policy[DPLL_A_ID + 1] = {
+	[DPLL_A_ID] = { .type = NLA_U32, },
+};
+
+/* DPLL_CMD_DEVICE_SET - do */
+static const struct nla_policy dpll_device_set_nl_policy[DPLL_A_FREQUENCY_MONITOR + 1] = {
+	[DPLL_A_ID] = { .type = NLA_U32, },
+	[DPLL_A_MODE] = NLA_POLICY_RANGE(NLA_U32, 1, 2),
+	[DPLL_A_PHASE_OFFSET_MONITOR] = NLA_POLICY_MAX(NLA_U32, 1),
+	[DPLL_A_PHASE_OFFSET_AVG_FACTOR] = { .type = NLA_U32, },
+	[DPLL_A_FREQUENCY_MONITOR] = NLA_POLICY_MAX(NLA_U32, 1),
+};
+
+/* DPLL_CMD_PIN_ID_GET - do */
+static const struct nla_policy dpll_pin_id_get_nl_policy[DPLL_A_PIN_TYPE + 1] = {
+	[DPLL_A_PIN_MODULE_NAME] = { .type = NLA_NUL_STRING, },
+	[DPLL_A_PIN_CLOCK_ID] = { .type = NLA_U64, },
+	[DPLL_A_PIN_BOARD_LABEL] = { .type = NLA_NUL_STRING, },
+	[DPLL_A_PIN_PANEL_LABEL] = { .type = NLA_NUL_STRING, },
+	[DPLL_A_PIN_PACKAGE_LABEL] = { .type = NLA_NUL_STRING, },
+	[DPLL_A_PIN_TYPE] = NLA_POLICY_RANGE(NLA_U32, 1, 6),
+};
+
+/* DPLL_CMD_PIN_GET - do */
+static const struct nla_policy dpll_pin_get_do_nl_policy[DPLL_A_PIN_ID + 1] = {
+	[DPLL_A_PIN_ID] = { .type = NLA_U32, },
+};
+
+/* DPLL_CMD_PIN_GET - dump */
+static const struct nla_policy dpll_pin_get_dump_nl_policy[DPLL_A_PIN_ID + 1] = {
+	[DPLL_A_PIN_ID] = { .type = NLA_U32, },
+};
+
+/* DPLL_CMD_PIN_SET - do */
+static const struct nla_policy dpll_pin_set_nl_policy[DPLL_A_PIN_REFERENCE_SYNC + 1] = {
+	[DPLL_A_PIN_ID] = { .type = NLA_U32, },
+	[DPLL_A_PIN_FREQUENCY] = { .type = NLA_U64, },
+	[DPLL_A_PIN_DIRECTION] = NLA_POLICY_RANGE(NLA_U32, 1, 2),
+	[DPLL_A_PIN_PRIO] = { .type = NLA_U32, },
+	[DPLL_A_PIN_STATE] = NLA_POLICY_RANGE(NLA_U32, 1, 3),
+	[DPLL_A_PIN_PARENT_DEVICE] = NLA_POLICY_NESTED(dpll_pin_parent_device_nl_policy),
+	[DPLL_A_PIN_PARENT_PIN] = NLA_POLICY_NESTED(dpll_pin_parent_pin_nl_policy),
+	[DPLL_A_PIN_PHASE_ADJUST] = { .type = NLA_S32, },
+	[DPLL_A_PIN_ESYNC_FREQUENCY] = { .type = NLA_U64, },
+	[DPLL_A_PIN_REFERENCE_SYNC] = NLA_POLICY_NESTED(dpll_reference_sync_nl_policy),
+};
+
+/* Ops table for dpll */
+static const struct genl_split_ops dpll_nl_ops[] = {
+	{
+		.cmd		= DPLL_CMD_DEVICE_ID_GET,
+		.pre_doit	= dpll_lock_doit,
+		.doit		= dpll_nl_device_id_get_doit,
+		.post_doit	= dpll_unlock_doit,
+		.policy		= dpll_device_id_get_nl_policy,
+		.maxattr	= DPLL_A_TYPE,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd		= DPLL_CMD_DEVICE_GET,
+		.pre_doit	= dpll_pre_doit,
+		.doit		= dpll_nl_device_get_doit,
+		.post_doit	= dpll_post_doit,
+		.policy		= dpll_device_get_nl_policy,
+		.maxattr	= DPLL_A_ID,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd	= DPLL_CMD_DEVICE_GET,
+		.dumpit	= dpll_nl_device_get_dumpit,
+		.flags	= GENL_ADMIN_PERM | GENL_CMD_CAP_DUMP,
+	},
+	{
+		.cmd		= DPLL_CMD_DEVICE_SET,
+		.pre_doit	= dpll_pre_doit,
+		.doit		= dpll_nl_device_set_doit,
+		.post_doit	= dpll_post_doit,
+		.policy		= dpll_device_set_nl_policy,
+		.maxattr	= DPLL_A_FREQUENCY_MONITOR,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd		= DPLL_CMD_PIN_ID_GET,
+		.pre_doit	= dpll_lock_doit,
+		.doit		= dpll_nl_pin_id_get_doit,
+		.post_doit	= dpll_unlock_doit,
+		.policy		= dpll_pin_id_get_nl_policy,
+		.maxattr	= DPLL_A_PIN_TYPE,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd		= DPLL_CMD_PIN_GET,
+		.pre_doit	= dpll_pin_pre_doit,
+		.doit		= dpll_nl_pin_get_doit,
+		.post_doit	= dpll_pin_post_doit,
+		.policy		= dpll_pin_get_do_nl_policy,
+		.maxattr	= DPLL_A_PIN_ID,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd		= DPLL_CMD_PIN_GET,
+		.dumpit		= dpll_nl_pin_get_dumpit,
+		.policy		= dpll_pin_get_dump_nl_policy,
+		.maxattr	= DPLL_A_PIN_ID,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DUMP,
+	},
+	{
+		.cmd		= DPLL_CMD_PIN_SET,
+		.pre_doit	= dpll_pin_pre_doit,
+		.doit		= dpll_nl_pin_set_doit,
+		.post_doit	= dpll_pin_post_doit,
+		.policy		= dpll_pin_set_nl_policy,
+		.maxattr	= DPLL_A_PIN_REFERENCE_SYNC,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+	},
+};
+
+static const struct genl_multicast_group dpll_nl_mcgrps[] = {
+	[DPLL_NLGRP_MONITOR] = { "monitor", },
+};
+
+struct genl_family dpll_nl_family __ro_after_init = {
+	.name		= DPLL_FAMILY_NAME,
+	.version	= DPLL_FAMILY_VERSION,
+	.netnsok	= true,
+	.parallel_ops	= true,
+	.module		= THIS_MODULE,
+	.split_ops	= dpll_nl_ops,
+	.n_split_ops	= ARRAY_SIZE(dpll_nl_ops),
+	.mcgrps		= dpll_nl_mcgrps,
+	.n_mcgrps	= ARRAY_SIZE(dpll_nl_mcgrps),
+};