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, 51 insertions, 0 deletions

diff --git a/net/atm/common.h b/net/atm/common.h
new file mode 100644
index 000000000..11cb51dd7
--- /dev/null
+++ b/net/atm/common.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* net/atm/common.h - ATM sockets (common part for PVC and SVC) */
+
+/* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */
+
+
+#ifndef NET_ATM_COMMON_H
+#define NET_ATM_COMMON_H
+
+#include <linux/net.h>
+#include <linux/poll.h> /* for poll_table */
+
+
+int vcc_create(struct net *net, struct socket *sock, int protocol, int family, int kern);
+int vcc_release(struct socket *sock);
+int vcc_connect(struct socket *sock, int itf, short vpi, int vci);
+int vcc_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
+		int flags);
+int vcc_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len);
+__poll_t vcc_poll(struct file *file, struct socket *sock, poll_table *wait);
+int vcc_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
+int vcc_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
+int vcc_setsockopt(struct socket *sock, int level, int optname,
+		   sockptr_t optval, unsigned int optlen);
+int vcc_getsockopt(struct socket *sock, int level, int optname,
+		   sockopt_t *opt);
+void vcc_process_recv_queue(struct atm_vcc *vcc);
+
+int atmpvc_init(void);
+void atmpvc_exit(void);
+int atm_sysfs_init(void);
+void atm_sysfs_exit(void);
+
+#ifdef CONFIG_PROC_FS
+int atm_proc_init(void);
+void atm_proc_exit(void);
+#else
+static inline int atm_proc_init(void)
+{
+	return 0;
+}
+
+static inline void atm_proc_exit(void)
+{
+	/* nothing */
+}
+#endif /* CONFIG_PROC_FS */
+
+void atm_dev_release_vccs(struct atm_dev *dev);
+
+#endif