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, 49 insertions, 0 deletions

diff --git a/fs/verity/Kconfig b/fs/verity/Kconfig
new file mode 100644
index 000000000..b20882963
--- /dev/null
+++ b/fs/verity/Kconfig
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config FS_VERITY
+	bool "FS Verity (read-only file-based authenticity protection)"
+	# Filesystems cache the Merkle tree at a 64K aligned offset in the
+	# pagecache.  That approach assumes the page size is at most 64K.
+	depends on PAGE_SHIFT <= 16
+	select CRYPTO_HASH_INFO
+	select CRYPTO_LIB_SHA256
+	select CRYPTO_LIB_SHA512
+	help
+	  This option enables fs-verity.  fs-verity is the dm-verity
+	  mechanism implemented at the file level.  On supported
+	  filesystems (currently ext4, f2fs, and btrfs), userspace can
+	  use an ioctl to enable verity for a file, which causes the
+	  filesystem to build a Merkle tree for the file.  The filesystem
+	  will then transparently verify any data read from the file
+	  against the Merkle tree.  The file is also made read-only.
+
+	  This serves as an integrity check, but the availability of the
+	  Merkle tree root hash also allows efficiently supporting
+	  various use cases where normally the whole file would need to
+	  be hashed at once, such as: (a) auditing (logging the file's
+	  hash), or (b) authenticity verification (comparing the hash
+	  against a known good value, e.g. from a digital signature).
+
+	  fs-verity is especially useful on large files where not all
+	  the contents may actually be needed.  Also, fs-verity verifies
+	  data each time it is paged back in, which provides better
+	  protection against malicious disks vs. an ahead-of-time hash.
+
+	  If unsure, say N.
+
+config FS_VERITY_BUILTIN_SIGNATURES
+	bool "FS Verity builtin signature support"
+	depends on FS_VERITY
+	select SYSTEM_DATA_VERIFICATION
+	help
+	  This option adds support for in-kernel verification of
+	  fs-verity builtin signatures.
+
+	  Please take great care before using this feature.  It is not
+	  the only way to do signatures with fs-verity, and the
+	  alternatives (such as userspace signature verification, and
+	  IMA appraisal) can be much better.  For details about the
+	  limitations of this feature, see
+	  Documentation/filesystems/fsverity.rst.
+
+	  If unsure, say N.