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, 33 insertions, 0 deletions

diff --git a/arch/arm/tools/syscallnr.sh b/arch/arm/tools/syscallnr.sh
new file mode 100644
index 000000000..9e386770b
--- /dev/null
+++ b/arch/arm/tools/syscallnr.sh
@@ -0,0 +1,33 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+in="$1"
+out="$2"
+align=1
+
+fileguard=_ASM_ARM_`basename "$out" | sed \
+    -e 'y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/' \
+    -e 's/[^A-Z0-9_]/_/g' -e 's/__/_/g'`
+
+grep -E "^[0-9A-Fa-fXx]+[[:space:]]+" "$in" | sort -n | tail -n1 | (
+    echo "#ifndef ${fileguard}
+#define ${fileguard} 1
+
+/*
+ * This needs to be greater than __NR_last_syscall+1 in order to account
+ * for the padding in the syscall table.
+ */
+"
+
+    while read nr abi name entry; do
+        nr=$(($nr + 1))
+        while [ "$(($nr / (256 * $align) ))" -gt 0 ]; do
+            align=$(( $align * 4 ))
+        done
+        nr=$(( ($nr + $align - 1) & ~($align - 1) ))
+        echo "/* aligned to $align */"
+        echo "#define __NR_syscalls $nr"
+    done
+
+    echo ""
+    echo "#endif /* ${fileguard} */"
+) > "$out"