From 27600805e62f800bacf990354632eae4e487d34c Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Thu, 3 Sep 2026 10:43:25 -0500 Subject: x86/amd_node: Fix PCI device reference counting in amd_smn_init() 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 Assisted-by: LLM Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Mario Limonciello (AMD) Cc: Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com --- include/net/arp.h | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 include/net/arp.h (limited to 'include/net/arp.h') diff --git a/include/net/arp.h b/include/net/arp.h new file mode 100644 index 000000000..e8747e071 --- /dev/null +++ b/include/net/arp.h @@ -0,0 +1,77 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* linux/net/inet/arp.h */ +#ifndef _ARP_H +#define _ARP_H + +#include +#include +#include + + +extern struct neigh_table arp_tbl; + +static inline u32 arp_hashfn(const void *pkey, const struct net_device *dev, u32 *hash_rnd) +{ + u32 key = *(const u32 *)pkey; + u32 val = key ^ hash32_ptr(dev); + + return val * hash_rnd[0]; +} + +#ifdef CONFIG_INET +static inline struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key) +{ + if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) + key = INADDR_ANY; + + return ___neigh_lookup_noref(&arp_tbl, neigh_key_eq32, arp_hashfn, &key, dev); +} +#else +static inline +struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key) +{ + return NULL; +} +#endif + +static inline struct neighbour *__ipv4_neigh_lookup(struct net_device *dev, u32 key) +{ + struct neighbour *n; + + rcu_read_lock(); + n = __ipv4_neigh_lookup_noref(dev, key); + if (n && !refcount_inc_not_zero(&n->refcnt)) + n = NULL; + rcu_read_unlock(); + + return n; +} + +static inline void __ipv4_confirm_neigh(struct net_device *dev, u32 key) +{ + struct neighbour *n; + + rcu_read_lock(); + n = __ipv4_neigh_lookup_noref(dev, key); + neigh_confirm(n); + rcu_read_unlock(); +} + +void arp_init(void); +int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg); +void arp_send(int type, int ptype, __be32 dest_ip, + struct net_device *dev, __be32 src_ip, + const unsigned char *dest_hw, + const unsigned char *src_hw, const unsigned char *th); +int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir); +void arp_ifdown(struct net_device *dev); +int arp_invalidate(struct net_device *dev, __be32 ip, bool force); + +struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, + struct net_device *dev, __be32 src_ip, + const unsigned char *dest_hw, + const unsigned char *src_hw, + const unsigned char *target_hw); +void arp_xmit(struct sk_buff *skb); + +#endif /* _ARP_H */ -- cgit v1.3.1