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, 107 insertions, 0 deletions

diff --git a/drivers/android/binder/trace.rs b/drivers/android/binder/trace.rs
new file mode 100644
index 000000000..06aabb3cc
--- /dev/null
+++ b/drivers/android/binder/trace.rs
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0
+
+// Copyright (C) 2025 Google LLC.
+
+use crate::transaction::Transaction;
+
+use core::ptr;
+
+use kernel::bindings::{rust_binder_transaction, task_struct};
+use kernel::error::Result;
+use kernel::ffi::{c_int, c_uint, c_ulong};
+use kernel::task::Task;
+use kernel::tracepoint::declare_trace;
+
+declare_trace! {
+    unsafe fn binder_ioctl(cmd: c_uint, arg: c_ulong);
+    unsafe fn binder_ioctl_done(ret: c_int);
+    unsafe fn binder_read_done(ret: c_int);
+    unsafe fn binder_write_done(ret: c_int);
+    unsafe fn binder_wait_for_work(proc_work: bool, transaction_stack: bool, thread_todo: bool);
+    unsafe fn binder_transaction(reply: bool, t: rust_binder_transaction, thread: *mut task_struct);
+    unsafe fn binder_transaction_received(t: rust_binder_transaction);
+    unsafe fn binder_transaction_fd_send(t_debug_id: c_int, fd: c_int, offset: usize);
+    unsafe fn binder_transaction_fd_recv(t_debug_id: c_int, fd: c_int, offset: usize);
+    unsafe fn binder_command(cmd: u32);
+    unsafe fn binder_return(ret: u32);
+}
+
+#[inline]
+fn raw_transaction(t: &Transaction) -> rust_binder_transaction {
+    ptr::from_ref(t).cast_mut().cast()
+}
+
+#[inline]
+fn to_errno(ret: Result) -> i32 {
+    match ret {
+        Ok(()) => 0,
+        Err(err) => err.to_errno(),
+    }
+}
+
+#[inline]
+pub(crate) fn trace_ioctl(cmd: u32, arg: usize) {
+    // SAFETY: Always safe to call.
+    unsafe { binder_ioctl(cmd, arg as c_ulong) }
+}
+
+#[inline]
+pub(crate) fn trace_ioctl_done(ret: Result) {
+    // SAFETY: Always safe to call.
+    unsafe { binder_ioctl_done(to_errno(ret)) }
+}
+#[inline]
+pub(crate) fn trace_read_done(ret: Result) {
+    // SAFETY: Always safe to call.
+    unsafe { binder_read_done(to_errno(ret)) }
+}
+#[inline]
+pub(crate) fn trace_write_done(ret: Result) {
+    // SAFETY: Always safe to call.
+    unsafe { binder_write_done(to_errno(ret)) }
+}
+
+#[inline]
+pub(crate) fn trace_wait_for_work(proc_work: bool, transaction_stack: bool, thread_todo: bool) {
+    // SAFETY: Always safe to call.
+    unsafe { binder_wait_for_work(proc_work, transaction_stack, thread_todo) }
+}
+
+#[inline]
+pub(crate) fn trace_transaction(reply: bool, t: &Transaction, thread: Option<&Task>) {
+    let thread = match thread {
+        Some(thread) => thread.as_ptr(),
+        None => core::ptr::null_mut(),
+    };
+    // SAFETY: The raw transaction is valid for the duration of this call. The thread pointer is
+    // valid or null.
+    unsafe { binder_transaction(reply, raw_transaction(t), thread) }
+}
+
+#[inline]
+pub(crate) fn trace_transaction_received(t: &Transaction) {
+    // SAFETY: The raw transaction is valid for the duration of this call.
+    unsafe { binder_transaction_received(raw_transaction(t)) }
+}
+
+#[inline]
+pub(crate) fn trace_transaction_fd_send(t_debug_id: usize, fd: u32, offset: usize) {
+    // SAFETY: This function is always safe to call.
+    unsafe { binder_transaction_fd_send(t_debug_id as c_int, fd as c_int, offset) }
+}
+#[inline]
+pub(crate) fn trace_transaction_fd_recv(t_debug_id: usize, fd: u32, offset: usize) {
+    // SAFETY: This function is always safe to call.
+    unsafe { binder_transaction_fd_recv(t_debug_id as c_int, fd as c_int, offset) }
+}
+
+#[inline]
+pub(crate) fn trace_command(cmd: u32) {
+    // SAFETY: This function is always safe to call.
+    unsafe { binder_command(cmd) }
+}
+#[inline]
+pub(crate) fn trace_return(ret: u32) {
+    // SAFETY: This function is always safe to call.
+    unsafe { binder_return(ret) }
+}