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, 61 insertions, 0 deletions

diff --git a/lib/tests/Makefile b/lib/tests/Makefile
new file mode 100644
index 000000000..3cac3b63a
--- /dev/null
+++ b/lib/tests/Makefile
@@ -0,0 +1,61 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for tests of kernel library functions.
+
+# KUnit tests
+CFLAGS_bitfield_kunit.o := $(DISABLE_STRUCTLEAK_PLUGIN)
+obj-$(CONFIG_BASE64_KUNIT) += base64_kunit.o
+obj-$(CONFIG_BITOPS_KUNIT) += bitops_kunit.o
+obj-$(CONFIG_BITFIELD_KUNIT) += bitfield_kunit.o
+obj-$(CONFIG_BITS_TEST) += test_bits.o
+obj-$(CONFIG_SHDI3_KUNIT_TEST) += shdi3_kunit.o
+obj-$(CONFIG_BLACKHOLE_DEV_KUNIT_TEST) += blackhole_dev_kunit.o
+obj-$(CONFIG_CHECKSUM_KUNIT) += checksum_kunit.o
+obj-$(CONFIG_CMDLINE_KUNIT_TEST) += cmdline_kunit.o
+obj-$(CONFIG_CPUMASK_KUNIT_TEST) += cpumask_kunit.o
+obj-$(CONFIG_FFS_KUNIT_TEST) += ffs_kunit.o
+CFLAGS_fortify_kunit.o += $(call cc-disable-warning, unsequenced)
+CFLAGS_fortify_kunit.o += $(call cc-disable-warning, stringop-overread)
+CFLAGS_fortify_kunit.o += $(call cc-disable-warning, stringop-truncation)
+CFLAGS_fortify_kunit.o += $(DISABLE_STRUCTLEAK_PLUGIN)
+obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o
+CFLAGS_test_fprobe.o += $(CC_FLAGS_FTRACE)
+obj-$(CONFIG_FPROBE_SANITY_TEST) += test_fprobe.o
+obj-$(CONFIG_GLOB_KUNIT_TEST) += glob_kunit.o
+obj-$(CONFIG_HASHTABLE_KUNIT_TEST) += hashtable_test.o
+obj-$(CONFIG_HASH_KUNIT_TEST) += test_hash.o
+obj-$(CONFIG_TEST_IOV_ITER) += kunit_iov_iter.o
+obj-$(CONFIG_IS_SIGNED_TYPE_KUNIT_TEST) += is_signed_type_kunit.o
+obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o
+obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o
+obj-$(CONFIG_LIST_PRIVATE_KUNIT_TEST) += list-private-test.o
+obj-$(CONFIG_KFIFO_KUNIT_TEST) += kfifo_kunit.o
+obj-$(CONFIG_TEST_LIST_SORT) += test_list_sort.o
+obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o
+obj-$(CONFIG_LIVEUPDATE_TEST) += liveupdate.o
+
+CFLAGS_longest_symbol_kunit.o += $(call cc-disable-warning, missing-prototypes)
+obj-$(CONFIG_LONGEST_SYM_KUNIT_TEST) += longest_symbol_kunit.o
+
+obj-$(CONFIG_MEMCPY_KUNIT_TEST) += memcpy_kunit.o
+obj-$(CONFIG_MIN_HEAP_KUNIT_TEST) += min_heap_kunit.o
+CFLAGS_overflow_kunit.o = $(call cc-disable-warning, tautological-constant-out-of-range-compare)
+obj-$(CONFIG_OVERFLOW_KUNIT_TEST) += overflow_kunit.o
+obj-$(CONFIG_PRANDOM_KUNIT_TEST) += random32_kunit.o
+obj-$(CONFIG_PRINTF_KUNIT_TEST) += printf_kunit.o
+obj-$(CONFIG_RANDSTRUCT_KUNIT_TEST) += randstruct_kunit.o
+obj-$(CONFIG_SCANF_KUNIT_TEST) += scanf_kunit.o
+obj-$(CONFIG_SEQ_BUF_KUNIT_TEST) += seq_buf_kunit.o
+obj-$(CONFIG_SIPHASH_KUNIT_TEST) += siphash_kunit.o
+obj-$(CONFIG_SLUB_KUNIT_TEST) += slub_kunit.o
+obj-$(CONFIG_TEST_SORT) += test_sort.o
+CFLAGS_stackinit_kunit.o += $(call cc-disable-warning, switch-unreachable)
+obj-$(CONFIG_STACKINIT_KUNIT_TEST) += stackinit_kunit.o
+obj-$(CONFIG_STRING_KUNIT_TEST) += string_kunit.o
+obj-$(CONFIG_STRING_HELPERS_KUNIT_TEST) += string_helpers_kunit.o
+obj-$(CONFIG_USERCOPY_KUNIT_TEST) += usercopy_kunit.o
+obj-$(CONFIG_UTIL_MACROS_KUNIT) += util_macros_kunit.o
+obj-$(CONFIG_RATELIMIT_KUNIT_TEST) += test_ratelimit.o
+obj-$(CONFIG_UUID_KUNIT_TEST) += uuid_kunit.o
+
+obj-$(CONFIG_TEST_RUNTIME_MODULE)		+= module/