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, 38 insertions, 0 deletions

diff --git a/fs/proc/Makefile b/fs/proc/Makefile
new file mode 100644
index 000000000..27e2b26b2
--- /dev/null
+++ b/fs/proc/Makefile
@@ -0,0 +1,38 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the Linux proc filesystem routines.
+#
+
+obj-y   += proc.o
+
+CFLAGS_task_mmu.o	+= -Wno-override-init
+proc-y			:= nommu.o task_nommu.o
+proc-$(CONFIG_MMU)	:= task_mmu.o
+
+proc-y       += inode.o root.o base.o generic.o array.o \
+		fd.o
+proc-$(CONFIG_TTY)      += proc_tty.o
+proc-y	+= cmdline.o
+proc-y	+= consoles.o
+proc-y	+= cpuinfo.o
+proc-y	+= devices.o
+ifneq ($(CONFIG_GENERIC_IRQ_SHOW),y)
+proc-y += interrupts.o
+endif
+proc-y	+= loadavg.o
+proc-y	+= meminfo.o
+proc-y	+= stat.o
+proc-y	+= uptime.o
+proc-y	+= util.o
+proc-y	+= version.o
+proc-y	+= softirqs.o
+proc-y	+= namespaces.o
+proc-y	+= self.o
+proc-y	+= thread_self.o
+proc-$(CONFIG_SYSCTL)		+= proc_sysctl.o
+proc-$(CONFIG_NET)		+= proc_net.o
+proc-$(CONFIG_PROC_KCORE)	+= kcore.o
+proc-$(CONFIG_PROC_VMCORE)	+= vmcore.o
+proc-$(CONFIG_PRINTK)	+= kmsg.o
+proc-$(CONFIG_PROC_PAGE_MONITOR)	+= page.o
+proc-$(CONFIG_BOOT_CONFIG)	+= bootconfig.o