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, 168 insertions, 0 deletions

diff --git a/include/crypto/internal/aead.h b/include/crypto/internal/aead.h
new file mode 100644
index 000000000..28a95eb31
--- /dev/null
+++ b/include/crypto/internal/aead.h
@@ -0,0 +1,168 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * AEAD: Authenticated Encryption with Associated Data
+ * 
+ * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#ifndef _CRYPTO_INTERNAL_AEAD_H
+#define _CRYPTO_INTERNAL_AEAD_H
+
+#include <crypto/aead.h>
+#include <crypto/algapi.h>
+#include <linux/stddef.h>
+#include <linux/types.h>
+
+struct rtattr;
+
+struct aead_instance {
+	void (*free)(struct aead_instance *inst);
+	union {
+		struct {
+			char head[offsetof(struct aead_alg, base)];
+			struct crypto_instance base;
+		} s;
+		struct aead_alg alg;
+	};
+};
+
+struct crypto_aead_spawn {
+	struct crypto_spawn base;
+};
+
+struct aead_queue {
+	struct crypto_queue base;
+};
+
+static inline void *crypto_aead_ctx(struct crypto_aead *tfm)
+{
+	return crypto_tfm_ctx(&tfm->base);
+}
+
+static inline void *crypto_aead_ctx_dma(struct crypto_aead *tfm)
+{
+	return crypto_tfm_ctx_dma(&tfm->base);
+}
+
+static inline struct crypto_instance *aead_crypto_instance(
+	struct aead_instance *inst)
+{
+	return container_of(&inst->alg.base, struct crypto_instance, alg);
+}
+
+static inline struct aead_instance *aead_instance(struct crypto_instance *inst)
+{
+	return container_of(&inst->alg, struct aead_instance, alg.base);
+}
+
+static inline struct aead_instance *aead_alg_instance(struct crypto_aead *aead)
+{
+	return aead_instance(crypto_tfm_alg_instance(&aead->base));
+}
+
+static inline void *aead_instance_ctx(struct aead_instance *inst)
+{
+	return crypto_instance_ctx(aead_crypto_instance(inst));
+}
+
+static inline void *aead_request_ctx(struct aead_request *req)
+{
+	return req->__ctx;
+}
+
+static inline void *aead_request_ctx_dma(struct aead_request *req)
+{
+	unsigned int align = crypto_dma_align();
+
+	if (align <= crypto_tfm_ctx_alignment())
+		align = 1;
+
+	return PTR_ALIGN(aead_request_ctx(req), align);
+}
+
+static inline void aead_request_complete(struct aead_request *req, int err)
+{
+	crypto_request_complete(&req->base, err);
+}
+
+static inline u32 aead_request_flags(struct aead_request *req)
+{
+	return req->base.flags;
+}
+
+static inline struct aead_request *aead_request_cast(
+	struct crypto_async_request *req)
+{
+	return container_of(req, struct aead_request, base);
+}
+
+int crypto_grab_aead(struct crypto_aead_spawn *spawn,
+		     struct crypto_instance *inst,
+		     const char *name, u32 type, u32 mask);
+
+static inline void crypto_drop_aead(struct crypto_aead_spawn *spawn)
+{
+	crypto_drop_spawn(&spawn->base);
+}
+
+static inline struct aead_alg *crypto_spawn_aead_alg(
+	struct crypto_aead_spawn *spawn)
+{
+	return container_of(spawn->base.alg, struct aead_alg, base);
+}
+
+static inline struct crypto_aead *crypto_spawn_aead(
+	struct crypto_aead_spawn *spawn)
+{
+	return crypto_spawn_tfm2(&spawn->base);
+}
+
+static inline void crypto_aead_set_reqsize(struct crypto_aead *aead,
+					   unsigned int reqsize)
+{
+	aead->reqsize = reqsize;
+}
+
+static inline void crypto_aead_set_reqsize_dma(struct crypto_aead *aead,
+					       unsigned int reqsize)
+{
+	reqsize += crypto_dma_align() & ~(crypto_tfm_ctx_alignment() - 1);
+	aead->reqsize = reqsize;
+}
+
+static inline void aead_init_queue(struct aead_queue *queue,
+				   unsigned int max_qlen)
+{
+	crypto_init_queue(&queue->base, max_qlen);
+}
+
+static inline unsigned int crypto_aead_alg_chunksize(struct aead_alg *alg)
+{
+	return alg->chunksize;
+}
+
+/**
+ * crypto_aead_chunksize() - obtain chunk size
+ * @tfm: cipher handle
+ *
+ * The block size is set to one for ciphers such as CCM.  However,
+ * you still need to provide incremental updates in multiples of
+ * the underlying block size as the IV does not have sub-block
+ * granularity.  This is known in this API as the chunk size.
+ *
+ * Return: chunk size in bytes
+ */
+static inline unsigned int crypto_aead_chunksize(struct crypto_aead *tfm)
+{
+	return crypto_aead_alg_chunksize(crypto_aead_alg(tfm));
+}
+
+int crypto_register_aead(struct aead_alg *alg);
+void crypto_unregister_aead(struct aead_alg *alg);
+int crypto_register_aeads(struct aead_alg *algs, int count);
+void crypto_unregister_aeads(struct aead_alg *algs, int count);
+int aead_register_instance(struct crypto_template *tmpl,
+			   struct aead_instance *inst);
+
+#endif	/* _CRYPTO_INTERNAL_AEAD_H */
+