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, 87 insertions, 0 deletions

diff --git a/drivers/accessibility/speakup/fakekey.c b/drivers/accessibility/speakup/fakekey.c
new file mode 100644
index 000000000..9c0b24038
--- /dev/null
+++ b/drivers/accessibility/speakup/fakekey.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* fakekey.c
+ * Functions for simulating key presses.
+ *
+ * Copyright (C) 2010 the Speakup Team
+ */
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/preempt.h>
+#include <linux/percpu.h>
+#include <linux/input.h>
+
+#include "speakup.h"
+
+#define PRESSED 1
+#define RELEASED 0
+
+static DEFINE_PER_CPU(int, reporting_keystroke);
+
+static struct input_dev *virt_keyboard;
+
+int speakup_add_virtual_keyboard(void)
+{
+	int err;
+
+	virt_keyboard = input_allocate_device();
+
+	if (!virt_keyboard)
+		return -ENOMEM;
+
+	virt_keyboard->name = "Speakup";
+	virt_keyboard->id.bustype = BUS_VIRTUAL;
+	virt_keyboard->phys = "speakup/input0";
+	virt_keyboard->dev.parent = NULL;
+
+	__set_bit(EV_KEY, virt_keyboard->evbit);
+	__set_bit(KEY_DOWN, virt_keyboard->keybit);
+
+	err = input_register_device(virt_keyboard);
+	if (err) {
+		input_free_device(virt_keyboard);
+		virt_keyboard = NULL;
+	}
+
+	return err;
+}
+
+void speakup_remove_virtual_keyboard(void)
+{
+	if (virt_keyboard) {
+		input_unregister_device(virt_keyboard);
+		virt_keyboard = NULL;
+	}
+}
+
+/*
+ * Send a simulated down-arrow to the application.
+ */
+void speakup_fake_down_arrow(void)
+{
+	unsigned long flags;
+
+	/* disable keyboard interrupts */
+	local_irq_save(flags);
+	/* don't change CPU */
+	preempt_disable();
+
+	__this_cpu_write(reporting_keystroke, true);
+	input_report_key(virt_keyboard, KEY_DOWN, PRESSED);
+	input_report_key(virt_keyboard, KEY_DOWN, RELEASED);
+	input_sync(virt_keyboard);
+	__this_cpu_write(reporting_keystroke, false);
+
+	/* re-enable preemption */
+	preempt_enable();
+	/* re-enable keyboard interrupts */
+	local_irq_restore(flags);
+}
+
+/*
+ * Are we handling a simulated key press on the current CPU?
+ * Returns a boolean.
+ */
+bool speakup_fake_key_pressed(void)
+{
+	return this_cpu_read(reporting_keystroke);
+}