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, 139 insertions, 0 deletions

diff --git a/net/mac80211/drop.h b/net/mac80211/drop.h
new file mode 100644
index 000000000..f06a8aa90
--- /dev/null
+++ b/net/mac80211/drop.h
@@ -0,0 +1,139 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * mac80211 drop reason list
+ *
+ * Copyright (C) 2023-2024, 2026 Intel Corporation
+ */
+
+#ifndef MAC80211_DROP_H
+#define MAC80211_DROP_H
+#include <net/dropreason.h>
+
+typedef unsigned int __bitwise ieee80211_rx_result;
+
+#define MAC80211_DROP_REASONS_UNUSABLE(R)	\
+	/* 0x00 == ___RX_DROP_UNUSABLE */	\
+	R(RX_DROP_U_MIC_FAIL)			\
+	R(RX_DROP_U_REPLAY)			\
+	R(RX_DROP_U_BAD_MMIE)			\
+	R(RX_DROP_U_DUP)			\
+	R(RX_DROP_U_SPURIOUS)			\
+	R(RX_DROP_U_DECRYPT_FAIL)		\
+	R(RX_DROP_U_NO_KEY_ID)			\
+	R(RX_DROP_U_BAD_CIPHER)			\
+	R(RX_DROP_U_OOM)			\
+	R(RX_DROP_U_NONSEQ_PN)			\
+	R(RX_DROP_U_BAD_KEY_COLOR)		\
+	R(RX_DROP_U_BAD_4ADDR)			\
+	R(RX_DROP_U_BAD_AMSDU)			\
+	R(RX_DROP_U_BAD_AMSDU_CIPHER)		\
+	R(RX_DROP_U_INVALID_8023)		\
+	/* 0x10 */				\
+	R(RX_DROP_U_RUNT_ACTION)		\
+	R(RX_DROP_U_UNPROT_ACTION)		\
+	R(RX_DROP_U_UNPROT_DUAL)		\
+	R(RX_DROP_U_UNPROT_UCAST_MGMT)		\
+	R(RX_DROP_U_UNPROT_MCAST_MGMT)		\
+	R(RX_DROP_U_UNPROT_BEACON)		\
+	R(RX_DROP_U_UNPROT_UNICAST_PUB_ACTION)	\
+	R(RX_DROP_U_UNPROT_ROBUST_ACTION)	\
+	R(RX_DROP_U_ACTION_UNKNOWN_SRC)		\
+	R(RX_DROP_U_REJECTED_ACTION_RESPONSE)	\
+	R(RX_DROP_U_EXPECT_DEFRAG_PROT)		\
+	R(RX_DROP_U_WEP_DEC_FAIL)		\
+	R(RX_DROP_U_NO_IV)			\
+	R(RX_DROP_U_NO_ICV)			\
+	R(RX_DROP_U_AP_RX_GROUPCAST)		\
+	R(RX_DROP_U_SHORT_MMIC)			\
+	/* 0x20 */				\
+	R(RX_DROP_U_MMIC_FAIL)			\
+	R(RX_DROP_U_SHORT_TKIP)			\
+	R(RX_DROP_U_TKIP_FAIL)			\
+	R(RX_DROP_U_SHORT_CCMP)			\
+	R(RX_DROP_U_SHORT_CCMP_MIC)		\
+	R(RX_DROP_U_SHORT_GCMP)			\
+	R(RX_DROP_U_SHORT_GCMP_MIC)		\
+	R(RX_DROP_U_SHORT_CMAC)			\
+	R(RX_DROP_U_SHORT_CMAC256)		\
+	R(RX_DROP_U_SHORT_GMAC)			\
+	R(RX_DROP_U_UNEXPECTED_VLAN_4ADDR)	\
+	R(RX_DROP_U_UNEXPECTED_STA_4ADDR)	\
+	R(RX_DROP_U_UNEXPECTED_VLAN_MCAST)	\
+	R(RX_DROP_U_NOT_PORT_CONTROL)		\
+	R(RX_DROP_U_UNEXPECTED_4ADDR_FRAME)	\
+	R(RX_DROP_U_BAD_BCN_KEYIDX)		\
+	/* 0x30 */				\
+	R(RX_DROP_U_BAD_MGMT_KEYIDX)		\
+	R(RX_DROP_U_UNKNOWN_ACTION_REJECTED)	\
+	R(RX_DROP_U_MESH_DS_BITS)		\
+	R(RX_DROP_U_MESH_A3_MISMATCH)		\
+	R(RX_DROP_U_MESH_NO_A4)			\
+	R(RX_DROP_U_MESH_A4_MISMATCH)		\
+	R(RX_DROP_U_MESH_UNEXP_DATA)		\
+	R(RX_DROP_U_MESH_WRONG_ACTION)		\
+	R(RX_DROP_U_MESH_UNEXP_MGMT)		\
+	R(RX_DROP_U_SPURIOUS_NOTIF)		\
+	R(RX_DROP_U_RUNT_DATA)			\
+	R(RX_DROP_U_KEY_TAINTED)		\
+	R(RX_DROP_U_UNPROTECTED)		\
+	R(RX_DROP_U_MCAST_FRAGMENT)		\
+	R(RX_DROP_U_DEFRAG_MISMATCH)		\
+	R(RX_DROP_U_RUNT_MESH_DATA)		\
+	/* 0x40 */				\
+	R(RX_DROP_U_MESH_NO_TTL)		\
+	R(RX_DROP_U_MESH_RMC)			\
+	R(RX_DROP_U_MESH_BAD_AE)		\
+	R(RX_DROP_U_MESH_TTL_EXPIRED)		\
+	R(RX_DROP_U_MESH_NOT_FORWARDING)	\
+	R(RX_DROP_U_AMSDU_WITHOUT_DATA)		\
+	R(RX_DROP_U_NULL_DATA)			\
+	R(RX_DROP_U_UNEXPECTED_4ADDR)		\
+	R(RX_DROP_U_PORT_CONTROL)		\
+	R(RX_DROP_U_UNKNOWN_STA)		\
+	R(RX_DROP_U_RUNT_BAR)			\
+	R(RX_DROP_U_BAR_OUTSIDE_SESSION)	\
+	R(RX_DROP_U_CTRL_FRAME)			\
+	R(RX_DROP_U_RUNT_MGMT)			\
+	R(RX_DROP_U_EXPECTED_MGMT)		\
+	R(RX_DROP_U_NONBCAST_BEACON)		\
+	/* 0x50 */				\
+	R(RX_DROP_U_MALFORMED_ACTION)		\
+	R(RX_DROP_U_UNKNOWN_MCAST_ACTION)	\
+	R(RX_DROP_U_UNEXPECTED_EXT_FRAME)	\
+	R(RX_DROP_U_UNHANDLED_MGMT)		\
+	R(RX_DROP_U_MCAST_DEAUTH)		\
+	R(RX_DROP_U_UNHANDLED_DEAUTH)		\
+	R(RX_DROP_U_MCAST_DISASSOC)		\
+	R(RX_DROP_U_UNHANDLED_DISASSOC)		\
+	R(RX_DROP_U_UNHANDLED_PREQ)		\
+	R(RX_DROP_U_UNHANDLED_MGMT_STYPE)	\
+	R(RX_DROP_U_NO_LINK)			\
+/* this line for the trailing \ - add before this */
+
+/* having two enums allows for checking ieee80211_rx_result use with sparse */
+enum ___mac80211_drop_reason {
+/* if we get to the end of handlers with RX_CONTINUE this will be the reason */
+	___RX_CONTINUE	= SKB_CONSUMED,
+
+/* this never gets used as an argument to kfree_skb_reason() */
+	___RX_QUEUED	= SKB_NOT_DROPPED_YET,
+
+#define ENUM(x) ___ ## x,
+	___RX_DROP_UNUSABLE = SKB_DROP_REASON_SUBSYS_MAC80211_UNUSABLE <<
+		SKB_DROP_REASON_SUBSYS_SHIFT,
+	MAC80211_DROP_REASONS_UNUSABLE(ENUM)
+#undef ENUM
+};
+
+enum mac80211_drop_reason {
+	RX_CONTINUE	= (__force ieee80211_rx_result)___RX_CONTINUE,
+	RX_QUEUED	= (__force ieee80211_rx_result)___RX_QUEUED,
+#define DEF(x) x = (__force ieee80211_rx_result)___ ## x,
+	MAC80211_DROP_REASONS_UNUSABLE(DEF)
+#undef DEF
+};
+
+#define RX_RES_IS_UNUSABLE(result)	\
+	(((__force u32)(result) & SKB_DROP_REASON_SUBSYS_MASK) == ___RX_DROP_UNUSABLE)
+
+#endif /* MAC80211_DROP_H */