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, 147 insertions, 0 deletions

diff --git a/net/rxrpc/sysctl.c b/net/rxrpc/sysctl.c
new file mode 100644
index 000000000..46a20cf4c
--- /dev/null
+++ b/net/rxrpc/sysctl.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* sysctls for configuring RxRPC operating parameters
+ *
+ * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/sysctl.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "ar-internal.h"
+
+static struct ctl_table_header *rxrpc_sysctl_reg_table;
+static const unsigned int rxrpc_rx_mtu_min = 500;
+static const unsigned int rxrpc_jumbo_max = RXRPC_MAX_NR_JUMBO;
+static const unsigned int four = 4;
+static const unsigned int max_backlog = RXRPC_BACKLOG_MAX - 1;
+static const unsigned int n_65535 = 65535;
+static const unsigned int n_max_acks = 255;
+static const unsigned long one_ms = 1;
+static const unsigned long max_ms = 1000;
+static const unsigned long one_jiffy = 1;
+static const unsigned long max_jiffies = MAX_JIFFY_OFFSET;
+#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
+static const unsigned long max_500 = 500;
+#endif
+
+/*
+ * RxRPC operating parameters.
+ *
+ * See Documentation/networking/rxrpc.rst and the variable definitions for more
+ * information on the individual parameters.
+ */
+static struct ctl_table rxrpc_sysctl_table[] = {
+	/* Values measured in milliseconds */
+	{
+		.procname	= "soft_ack_delay",
+		.data		= &rxrpc_soft_ack_delay,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= proc_doulongvec_minmax,
+		.extra1		= (void *)&one_ms,
+		.extra2		= (void *)&max_ms,
+	},
+	{
+		.procname	= "idle_ack_delay",
+		.data		= &rxrpc_idle_ack_delay,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= proc_doulongvec_minmax,
+		.extra1		= (void *)&one_ms,
+		.extra2		= (void *)&max_ms,
+	},
+	{
+		.procname	= "idle_conn_expiry",
+		.data		= &rxrpc_conn_idle_client_expiry,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= proc_doulongvec_ms_jiffies_minmax,
+		.extra1		= (void *)&one_jiffy,
+		.extra2		= (void *)&max_jiffies,
+	},
+	{
+		.procname	= "idle_conn_fast_expiry",
+		.data		= &rxrpc_conn_idle_client_fast_expiry,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= proc_doulongvec_ms_jiffies_minmax,
+		.extra1		= (void *)&one_jiffy,
+		.extra2		= (void *)&max_jiffies,
+	},
+
+	/* Values used in milliseconds */
+#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
+	{
+		.procname	= "inject_rx_delay",
+		.data		= &rxrpc_inject_rx_delay,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= proc_doulongvec_minmax,
+		.extra1		= (void *)SYSCTL_LONG_ZERO,
+		.extra2		= (void *)&max_500,
+	},
+#endif
+
+	/* Non-time values */
+	{
+		.procname	= "reap_client_conns",
+		.data		= &rxrpc_reap_client_connections,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= (void *)SYSCTL_ONE,
+		.extra2		= (void *)&n_65535,
+	},
+	{
+		.procname	= "max_backlog",
+		.data		= &rxrpc_max_backlog,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= (void *)&four,
+		.extra2		= (void *)&max_backlog,
+	},
+	{
+		.procname	= "rx_window_size",
+		.data		= &rxrpc_rx_window_size,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= (void *)SYSCTL_ONE,
+		.extra2		= (void *)&n_max_acks,
+	},
+	{
+		.procname	= "rx_mtu",
+		.data		= &rxrpc_rx_mtu,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= (void *)&rxrpc_rx_mtu_min,
+		.extra2		= (void *)&n_65535,
+	},
+	{
+		.procname	= "rx_jumbo_max",
+		.data		= &rxrpc_rx_jumbo_max,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= (void *)SYSCTL_ONE,
+		.extra2		= (void *)&rxrpc_jumbo_max,
+	},
+};
+
+int __init rxrpc_sysctl_init(void)
+{
+	rxrpc_sysctl_reg_table = register_net_sysctl(&init_net, "net/rxrpc",
+						     rxrpc_sysctl_table);
+	if (!rxrpc_sysctl_reg_table)
+		return -ENOMEM;
+	return 0;
+}
+
+void rxrpc_sysctl_exit(void)
+{
+	if (rxrpc_sysctl_reg_table)
+		unregister_net_sysctl_table(rxrpc_sysctl_reg_table);
+}