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, 215 insertions, 0 deletions

diff --git a/include/trace/events/erofs.h b/include/trace/events/erofs.h
new file mode 100644
index 000000000..0a178cb10
--- /dev/null
+++ b/include/trace/events/erofs.h
@@ -0,0 +1,215 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM erofs
+
+#if !defined(_TRACE_EROFS_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_EROFS_H
+
+#include <linux/tracepoint.h>
+#include <linux/fs.h>
+
+struct erofs_map_blocks;
+
+#define show_dev(dev)		MAJOR(dev), MINOR(dev)
+#define show_dev_nid(entry)	show_dev(entry->dev), entry->nid
+
+#define show_file_type(type)						\
+	__print_symbolic(type,						\
+		{ 0,		"FILE" },				\
+		{ 1,		"DIR" })
+
+#define show_map_flags(flags) __print_flags(flags, "|",	\
+	{ EROFS_GET_BLOCKS_FIEMAP,	"FIEMAP" },	\
+	{ EROFS_GET_BLOCKS_READMORE,	"READMORE" },	\
+	{ EROFS_GET_BLOCKS_FINDTAIL,	"FINDTAIL" })
+
+#define show_mflags(flags) __print_flags(flags, "",	\
+	{ EROFS_MAP_MAPPED,		"M" },		\
+	{ EROFS_MAP_META,		"I" },		\
+	{ EROFS_MAP_PARTIAL_MAPPED,	"T" },		\
+	{ EROFS_MAP_PARTIAL_REF,	"P" },		\
+	{ EROFS_MAP_FRAGMENT,		"R" })
+
+TRACE_EVENT(erofs_lookup,
+
+	TP_PROTO(struct inode *dir, struct dentry *dentry, unsigned int flags),
+
+	TP_ARGS(dir, dentry, flags),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev	)
+		__field(erofs_nid_t,	nid	)
+		__string(name,		dentry->d_name.name	)
+		__field(unsigned int,	flags	)
+	),
+
+	TP_fast_assign(
+		__entry->dev	= dir->i_sb->s_dev;
+		__entry->nid	= EROFS_I(dir)->nid;
+		__assign_str(name);
+		__entry->flags	= flags;
+	),
+
+	TP_printk("dev = (%d,%d), pnid = %llu, name:%s, flags:%x",
+		show_dev_nid(__entry),
+		__get_str(name),
+		__entry->flags)
+);
+
+TRACE_EVENT(erofs_fill_inode,
+	TP_PROTO(struct inode *inode),
+	TP_ARGS(inode),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev	)
+		__field(erofs_nid_t,	nid	)
+		__field(erofs_blk_t,	blkaddr )
+		__field(unsigned int,	ofs	)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= inode->i_sb->s_dev;
+		__entry->nid		= EROFS_I(inode)->nid;
+		__entry->blkaddr	= erofs_blknr(inode->i_sb, erofs_iloc(inode));
+		__entry->ofs		= erofs_blkoff(inode->i_sb, erofs_iloc(inode));
+	),
+
+	TP_printk("dev = (%d,%d), nid = %llu, blkaddr %llu ofs %u",
+		  show_dev_nid(__entry),
+		  __entry->blkaddr, __entry->ofs)
+);
+
+TRACE_EVENT(erofs_read_folio,
+
+	TP_PROTO(struct inode *inode, struct folio *folio, bool raw),
+
+	TP_ARGS(inode, folio, raw),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev	)
+		__field(erofs_nid_t,    nid     )
+		__field(int,		dir	)
+		__field(pgoff_t,	index	)
+		__field(unsigned int,	order	)
+		__field(bool,		raw	)
+	),
+
+	TP_fast_assign(
+		__entry->dev	= inode->i_sb->s_dev;
+		__entry->nid	= EROFS_I(inode)->nid;
+		__entry->dir	= S_ISDIR(inode->i_mode);
+		__entry->index	= folio->index;
+		__entry->order	= folio_order(folio);
+		__entry->raw = raw;
+	),
+
+	TP_printk("dev = (%d,%d), nid = %llu, %s, index = %lu, order = %u, raw = %d",
+		show_dev_nid(__entry),
+		show_file_type(__entry->dir),
+		(unsigned long)__entry->index,
+		__entry->order,
+		__entry->raw)
+);
+
+TRACE_EVENT(erofs_readahead,
+
+	TP_PROTO(struct inode *inode, pgoff_t start, unsigned int nrpage,
+		bool raw),
+
+	TP_ARGS(inode, start, nrpage, raw),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev	)
+		__field(erofs_nid_t,	nid	)
+		__field(pgoff_t,	start	)
+		__field(unsigned int,	nrpage	)
+		__field(bool,		raw	)
+	),
+
+	TP_fast_assign(
+		__entry->dev	= inode->i_sb->s_dev;
+		__entry->nid	= EROFS_I(inode)->nid;
+		__entry->start	= start;
+		__entry->nrpage	= nrpage;
+		__entry->raw	= raw;
+	),
+
+	TP_printk("dev = (%d,%d), nid = %llu, start = %lu nrpage = %u raw = %d",
+		show_dev_nid(__entry),
+		(unsigned long)__entry->start,
+		__entry->nrpage,
+		__entry->raw)
+);
+
+TRACE_EVENT(erofs_map_blocks_enter,
+
+	TP_PROTO(struct inode *inode, struct erofs_map_blocks *map,
+		 unsigned int flags),
+
+	TP_ARGS(inode, map, flags),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,		dev		)
+		__field(	erofs_nid_t,	nid		)
+		__field(	erofs_off_t,	la		)
+		__field(	u64,		llen		)
+		__field(	unsigned int,	flags		)
+	),
+
+	TP_fast_assign(
+		__entry->dev    = inode->i_sb->s_dev;
+		__entry->nid    = EROFS_I(inode)->nid;
+		__entry->la	= map->m_la;
+		__entry->llen	= map->m_llen;
+		__entry->flags	= flags;
+	),
+
+	TP_printk("dev = (%d,%d), nid = %llu, la %llu llen %llu flags %s",
+		  show_dev_nid(__entry),
+		  __entry->la, __entry->llen,
+		  __entry->flags ? show_map_flags(__entry->flags) : "NULL")
+);
+
+TRACE_EVENT(erofs_map_blocks_exit,
+
+	TP_PROTO(struct inode *inode, struct erofs_map_blocks *map,
+		 unsigned int flags, int ret),
+
+	TP_ARGS(inode, map, flags, ret),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,		dev		)
+		__field(	erofs_nid_t,	nid		)
+		__field(        unsigned int,   flags           )
+		__field(	erofs_off_t,	la		)
+		__field(	erofs_off_t,	pa		)
+		__field(	u64,		llen		)
+		__field(	u64,		plen		)
+		__field(        unsigned int,	mflags		)
+		__field(	int,		ret		)
+	),
+
+	TP_fast_assign(
+		__entry->dev    = inode->i_sb->s_dev;
+		__entry->nid    = EROFS_I(inode)->nid;
+		__entry->flags	= flags;
+		__entry->la	= map->m_la;
+		__entry->pa	= map->m_pa;
+		__entry->llen	= map->m_llen;
+		__entry->plen	= map->m_plen;
+		__entry->mflags	= map->m_flags;
+		__entry->ret	= ret;
+	),
+
+	TP_printk("dev = (%d,%d), nid = %llu, flags %s "
+		  "la %llu pa %llu llen %llu plen %llu mflags %s ret %d",
+		  show_dev_nid(__entry),
+		  __entry->flags ? show_map_flags(__entry->flags) : "NULL",
+		  __entry->la, __entry->pa, __entry->llen, __entry->plen,
+		  show_mflags(__entry->mflags), __entry->ret)
+);
+
+#endif /* _TRACE_EROFS_H */
+
+ /* This part must be outside protection */
+#include <trace/define_trace.h>