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, 197 insertions, 0 deletions

diff --git a/io_uring/xattr.c b/io_uring/xattr.c
new file mode 100644
index 000000000..5303df3f2
--- /dev/null
+++ b/io_uring/xattr.c
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/namei.h>
+#include <linux/io_uring.h>
+#include <linux/xattr.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "../fs/internal.h"
+
+#include "io_uring.h"
+#include "xattr.h"
+
+struct io_xattr {
+	struct file			*file;
+	struct kernel_xattr_ctx		ctx;
+	struct delayed_filename		filename;
+};
+
+void io_xattr_cleanup(struct io_kiocb *req)
+{
+	struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
+
+	dismiss_delayed_filename(&ix->filename);
+	kfree(ix->ctx.kname);
+	kvfree(ix->ctx.kvalue);
+}
+
+static void io_xattr_finish(struct io_kiocb *req, int ret)
+{
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+
+	io_xattr_cleanup(req);
+	io_req_set_res(req, ret, 0);
+}
+
+static int __io_getxattr_prep(struct io_kiocb *req,
+			      const struct io_uring_sqe *sqe)
+{
+	struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
+	const char __user *name;
+	int ret;
+
+	INIT_DELAYED_FILENAME(&ix->filename);
+	ix->ctx.kvalue = NULL;
+	name = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	ix->ctx.value = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	ix->ctx.size = READ_ONCE(sqe->len);
+	ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
+
+	if (ix->ctx.flags)
+		return -EINVAL;
+
+	ix->ctx.kname = kmalloc_obj(*ix->ctx.kname);
+	if (!ix->ctx.kname)
+		return -ENOMEM;
+
+	ret = import_xattr_name(ix->ctx.kname, name);
+	if (ret) {
+		kfree(ix->ctx.kname);
+		return ret;
+	}
+
+	req->flags |= REQ_F_NEED_CLEANUP;
+	req->flags |= REQ_F_FORCE_ASYNC;
+	return 0;
+}
+
+int io_fgetxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	return __io_getxattr_prep(req, sqe);
+}
+
+int io_getxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
+	const char __user *path;
+	int ret;
+
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	ret = __io_getxattr_prep(req, sqe);
+	if (ret)
+		return ret;
+
+	path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
+
+	return delayed_getname(&ix->filename, path);
+}
+
+int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
+	int ret;
+
+	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
+
+	ret = file_getxattr(req->file, &ix->ctx);
+	io_xattr_finish(req, ret);
+	return IOU_COMPLETE;
+}
+
+int io_getxattr(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
+	CLASS(filename_complete_delayed, name)(&ix->filename);
+	int ret;
+
+	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
+
+	ret = filename_getxattr(AT_FDCWD, name, LOOKUP_FOLLOW, &ix->ctx);
+	io_xattr_finish(req, ret);
+	return IOU_COMPLETE;
+}
+
+static int __io_setxattr_prep(struct io_kiocb *req,
+			const struct io_uring_sqe *sqe)
+{
+	struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
+	const char __user *name;
+	int ret;
+
+	INIT_DELAYED_FILENAME(&ix->filename);
+	name = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	ix->ctx.cvalue = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	ix->ctx.kvalue = NULL;
+	ix->ctx.size = READ_ONCE(sqe->len);
+	ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
+
+	ix->ctx.kname = kmalloc_obj(*ix->ctx.kname);
+	if (!ix->ctx.kname)
+		return -ENOMEM;
+
+	ret = setxattr_copy(name, &ix->ctx);
+	if (ret) {
+		kfree(ix->ctx.kname);
+		return ret;
+	}
+
+	req->flags |= REQ_F_NEED_CLEANUP;
+	req->flags |= REQ_F_FORCE_ASYNC;
+	return 0;
+}
+
+int io_setxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
+	const char __user *path;
+	int ret;
+
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	ret = __io_setxattr_prep(req, sqe);
+	if (ret)
+		return ret;
+
+	path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
+
+	return delayed_getname(&ix->filename, path);
+}
+
+int io_fsetxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	return __io_setxattr_prep(req, sqe);
+}
+
+int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
+	int ret;
+
+	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
+
+	ret = file_setxattr(req->file, &ix->ctx);
+	io_xattr_finish(req, ret);
+	return IOU_COMPLETE;
+}
+
+int io_setxattr(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
+	CLASS(filename_complete_delayed, name)(&ix->filename);
+	int ret;
+
+	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
+
+	ret = filename_setxattr(AT_FDCWD, name, LOOKUP_FOLLOW, &ix->ctx);
+	io_xattr_finish(req, ret);
+	return IOU_COMPLETE;
+}