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, 76 insertions, 0 deletions

diff --git a/tools/testing/selftests/clock-helpers.h b/tools/testing/selftests/clock-helpers.h
new file mode 100644
index 000000000..01451f538
--- /dev/null
+++ b/tools/testing/selftests/clock-helpers.h
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __CLOCK_HELPERS_H
+#define __CLOCK_HELPERS_H
+
+#include <sys/types.h>
+#include <time.h>
+
+#define MSEC_PER_SEC	1000LL
+#define USEC_PER_MSEC	1000LL
+#define NSEC_PER_USEC	1000LL
+#define NSEC_PER_MSEC	1000000LL
+#define USEC_PER_SEC	1000000LL
+#define NSEC_PER_SEC	1000000000LL
+#define PSEC_PER_SEC	1000000000000LL
+#define FSEC_PER_SEC	1000000000000000LL
+
+#ifndef CLOCK_AUX
+#define CLOCK_AUX	16
+#endif
+
+#ifndef MAX_AUX_CLOCKS
+#define MAX_AUX_CLOCKS	8
+#endif
+
+#ifndef CLOCK_AUX_LAST
+#define CLOCK_AUX_LAST	(CLOCK_AUX + MAX_AUX_CLOCKS - 1)
+#endif
+
+__attribute__((unused))
+static inline const char *clock_name(clockid_t clockid)
+{
+	switch (clockid) {
+	case CLOCK_REALTIME:
+		return "CLOCK_REALTIME";
+	case CLOCK_MONOTONIC:
+		return "CLOCK_MONOTONIC";
+	case CLOCK_PROCESS_CPUTIME_ID:
+		return "CLOCK_PROCESS_CPUTIME_ID";
+	case CLOCK_THREAD_CPUTIME_ID:
+		return "CLOCK_THREAD_CPUTIME_ID";
+	case CLOCK_MONOTONIC_RAW:
+		return "CLOCK_MONOTONIC_RAW";
+	case CLOCK_REALTIME_COARSE:
+		return "CLOCK_REALTIME_COARSE";
+	case CLOCK_MONOTONIC_COARSE:
+		return "CLOCK_MONOTONIC_COARSE";
+	case CLOCK_BOOTTIME:
+		return "CLOCK_BOOTTIME";
+	case CLOCK_REALTIME_ALARM:
+		return "CLOCK_REALTIME_ALARM";
+	case CLOCK_BOOTTIME_ALARM:
+		return "CLOCK_BOOTTIME_ALARM";
+	case CLOCK_TAI:
+		return "CLOCK_TAI";
+	case CLOCK_AUX + 0:
+		return "CLOCK_AUX0";
+	case CLOCK_AUX + 1:
+		return "CLOCK_AUX1";
+	case CLOCK_AUX + 2:
+		return "CLOCK_AUX2";
+	case CLOCK_AUX + 3:
+		return "CLOCK_AUX3";
+	case CLOCK_AUX + 4:
+		return "CLOCK_AUX4";
+	case CLOCK_AUX + 5:
+		return "CLOCK_AUX5";
+	case CLOCK_AUX + 6:
+		return "CLOCK_AUX6";
+	case CLOCK_AUX + 7:
+		return "CLOCK_AUX7";
+	};
+	return "UNKNOWN_CLOCKID";
+}
+
+#endif /* __CLOCK_HELPERS_H */