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, 57 insertions, 0 deletions

diff --git a/arch/arm/tools/Makefile b/arch/arm/tools/Makefile
new file mode 100644
index 000000000..28b6da8ac
--- /dev/null
+++ b/arch/arm/tools/Makefile
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# linux/arch/arm/tools/Makefile
+#
+# Copyright (C) 2001 Russell King
+#
+
+gen := arch/$(ARCH)/include/generated
+kapi := $(gen)/asm
+uapi := $(gen)/uapi/asm
+syshdr := $(srctree)/scripts/syscallhdr.sh
+sysnr := $(src)/syscallnr.sh
+systbl := $(srctree)/scripts/syscalltbl.sh
+syscall := $(src)/syscall.tbl
+
+gen-y := $(gen)/calls-oabi.S
+gen-y += $(gen)/calls-eabi.S
+kapi-hdrs-y := $(kapi)/unistd-nr.h
+kapi-hdrs-y += $(kapi)/mach-types.h
+uapi-hdrs-y += $(uapi)/unistd-oabi.h
+uapi-hdrs-y += $(uapi)/unistd-eabi.h
+
+targets += $(addprefix ../../../,$(gen-y) $(kapi-hdrs-y) $(uapi-hdrs-y))
+
+PHONY += kapi uapi
+
+kapi:	$(kapi-hdrs-y) $(gen-y)
+
+uapi:	$(uapi-hdrs-y)
+
+# Create output directory if not already present
+$(shell mkdir -p $(kapi) $(uapi))
+
+quiet_cmd_gen_mach = GEN     $@
+      cmd_gen_mach = $(AWK) -f $(real-prereqs) > $@
+
+$(kapi)/mach-types.h: $(src)/gen-mach-types $(src)/mach-types FORCE
+	$(call if_changed,gen_mach)
+
+quiet_cmd_syshdr = SYSHDR  $@
+      cmd_syshdr = $(CONFIG_SHELL) $(syshdr) --abis common,$* \
+		   --offset __NR_SYSCALL_BASE $< $@
+
+quiet_cmd_systbl = SYSTBL  $@
+      cmd_systbl = $(CONFIG_SHELL) $(systbl) --abis common,$* $< $@
+
+quiet_cmd_sysnr  = SYSNR   $@
+      cmd_sysnr  = $(CONFIG_SHELL) $(sysnr) $< $@
+
+$(uapi)/unistd-%.h: $(syscall) $(syshdr) FORCE
+	$(call if_changed,syshdr)
+
+$(kapi)/unistd-nr.h: $(syscall) $(sysnr) FORCE
+	$(call if_changed,sysnr)
+
+$(gen)/calls-%.S: $(syscall) $(systbl) FORCE
+	$(call if_changed,systbl)