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authorLinus Torvalds <torvalds@linux-foundation.org>2026-09-25 15:55:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-09-25 15:55:03 -0700
commit75467f60a3d14f08f86f2b353298d2826382ff23 (patch)
treeacd8a7d5b5a675042449386efa5b42ec44d8bf81 /Documentation/devicetree/changesets.rst
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Merge tag 'ipe-pr-20260925' of git://git.kernel.org/pub/scm/linux/kernel/git/wufan/ipegrafted
Pull IPE fixes from Fan Wu: "Two fixes for use-after-free issues found by recent LLM-assisted code analysis. - move successful policy load auditing under the new policy directory's inode lock, preventing a concurrent policy deletion from freeing the policy while it is still being audited - protect the dm-verity root hash with RCU, preventing policy evaluation from racing with root hash replacement during preresume" * tag 'ipe-pr-20260925' of git://git.kernel.org/pub/scm/linux/kernel/git/wufan/ipe: ipe: protect the dm-verity root hash with RCU ipe: fix use-after-free when auditing a newly loaded policy
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+.. SPDX-License-Identifier: GPL-2.0
+
+=====================
+Devicetree Changesets
+=====================
+
+A Devicetree changeset is a method which allows one to apply changes
+in the live tree in such a way that either the full set of changes
+will be applied, or none of them will be. If an error occurs partway
+through applying the changeset, then the tree will be rolled back to the
+previous state. A changeset can also be removed after it has been
+applied.
+
+When a changeset is applied, all of the changes get applied to the tree
+at once before emitting OF_RECONFIG notifiers. This is so that the
+receiver sees a complete and consistent state of the tree when it
+receives the notifier.
+
+The sequence of a changeset is as follows.
+
+1. of_changeset_init() - initializes a changeset
+
+2. A number of DT tree change calls, of_changeset_attach_node(),
+ of_changeset_detach_node(), of_changeset_add_property(),
+ of_changeset_remove_property, of_changeset_update_property() to prepare
+ a set of changes. No changes to the active tree are made at this point.
+ All the change operations are recorded in the of_changeset 'entries'
+ list.
+
+3. of_changeset_apply() - Apply the changes to the tree. Either the
+ entire changeset will get applied, or if there is an error the tree will
+ be restored to the previous state. The core ensures proper serialization
+ through locking. An unlocked version __of_changeset_apply is available,
+ if needed.
+
+If a successfully applied changeset needs to be removed, it can be done
+with of_changeset_revert().