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, 51 insertions, 0 deletions

diff --git a/include/trace/events/fsnotify.h b/include/trace/events/fsnotify.h
new file mode 100644
index 000000000..341bbd57a
--- /dev/null
+++ b/include/trace/events/fsnotify.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM fsnotify
+
+#if !defined(_TRACE_FSNOTIFY_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_FSNOTIFY_H
+
+#include <linux/tracepoint.h>
+
+#include <trace/misc/fsnotify.h>
+
+TRACE_EVENT(fsnotify,
+	TP_PROTO(__u32 mask, const void *data, int data_type,
+		 struct inode *dir, const struct qstr *file_name,
+		 struct inode *inode, u32 cookie),
+
+	TP_ARGS(mask, data, data_type, dir, file_name, inode, cookie),
+
+	TP_STRUCT__entry(
+		__field(__u32, mask)
+		__field(unsigned long, dir_ino)
+		__field(unsigned long, ino)
+		__field(dev_t, s_dev)
+		__field(int, data_type)
+		__field(u32, cookie)
+		__string(file_name, file_name ? (const char *)file_name->name : "")
+	),
+
+	TP_fast_assign(
+		__entry->mask = mask;
+		__entry->dir_ino = dir ? dir->i_ino : 0;
+		__entry->ino = inode ? inode->i_ino : 0;
+		__entry->s_dev = dir ? dir->i_sb->s_dev :
+				 inode ? inode->i_sb->s_dev : 0;
+		__entry->data_type = data_type;
+		__entry->cookie = cookie;
+		__assign_str(file_name);
+	),
+
+	TP_printk("dev=%d:%d dir=%lu ino=%lu data_type=%d cookie=0x%x mask=0x%x %s name=%s",
+		  MAJOR(__entry->s_dev), MINOR(__entry->s_dev),
+		  __entry->dir_ino, __entry->ino,
+		  __entry->data_type, __entry->cookie,
+		  __entry->mask, show_fsnotify_mask(__entry->mask),
+		  __get_str(file_name))
+);
+
+#endif /* _TRACE_FSNOTIFY_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>