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/tools/perf/util/capstone.h b/tools/perf/util/capstone.h
new file mode 100644
index 000000000..7c0baaa01
--- /dev/null
+++ b/tools/perf/util/capstone.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PERF_CAPSTONE_H
+#define __PERF_CAPSTONE_H
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <linux/compiler.h>
+#include <linux/types.h>
+
+struct annotate_args;
+struct machine;
+struct symbol;
+struct thread;
+
+#ifdef HAVE_LIBCAPSTONE_SUPPORT
+ssize_t capstone__fprintf_insn_asm(struct machine *machine, struct thread *thread, u8 cpumode,
+				   bool is64bit, const uint8_t *code, size_t code_size,
+				   uint64_t ip, int *lenp, int print_opts, FILE *fp);
+int symbol__disassemble_capstone(const char *filename, struct symbol *sym,
+				 struct annotate_args *args);
+int symbol__disassemble_capstone_powerpc(const char *filename, struct symbol *sym,
+					 struct annotate_args *args);
+
+#else /* !HAVE_LIBCAPSTONE_SUPPORT */
+static inline ssize_t capstone__fprintf_insn_asm(struct machine *machine __maybe_unused,
+						 struct thread *thread __maybe_unused,
+						 u8 cpumode __maybe_unused,
+						 bool is64bit __maybe_unused,
+						 const uint8_t *code __maybe_unused,
+						 size_t code_size __maybe_unused,
+						 uint64_t ip __maybe_unused,
+						 int *lenp __maybe_unused,
+						 int print_opts __maybe_unused,
+						 FILE *fp __maybe_unused)
+{
+	return -1;
+}
+
+static inline int symbol__disassemble_capstone(const char *filename __maybe_unused,
+					       struct symbol *sym __maybe_unused,
+					       struct annotate_args *args __maybe_unused)
+{
+	return -1;
+}
+
+static inline int symbol__disassemble_capstone_powerpc(const char *filename __maybe_unused,
+						       struct symbol *sym __maybe_unused,
+						       struct annotate_args *args __maybe_unused)
+{
+	return -1;
+}
+
+#endif /* HAVE_LIBCAPSTONE_SUPPORT */
+
+#endif /* __PERF_CAPSTONE_H */