From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- Documentation/process/maintainer-devicetree.rst | 72 +++++++++++++++++++++++++ 1 file changed, 72 insertions(+) create mode 100644 Documentation/process/maintainer-devicetree.rst (limited to 'Documentation/process/maintainer-devicetree.rst') diff --git a/Documentation/process/maintainer-devicetree.rst b/Documentation/process/maintainer-devicetree.rst new file mode 100644 index 000000000..ecc3ed638 --- /dev/null +++ b/Documentation/process/maintainer-devicetree.rst @@ -0,0 +1,72 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================================== +Devicetree and Open Firmware Subsystem +====================================== + +Other Process Documents +----------------------- + +Please see the documents in Documentation/devicetree/bindings/ for information +on how to write proper Devicetree bindings and how to submit patches. + +Patch Review and Handling +------------------------- + +Patches handled by Devicetree maintainers are processed differently depending +on the patch type: + +1. Core OF driver code, e.g. drivers/of/: + patches are reviewed and applied by DT maintainers. + +2. Devicetree bindings: + patches are reviewed by DT maintainers, but should be applied by subsystem + maintainers except in certain cases. See also *For kernel maintainers* in + Documentation/devicetree/bindings/submitting-patches.rst. + +3. DTS and drivers: + DT maintainers might provide comments, but review is generally not expected. + DTS must pass schema checks (dtbs_check) or at least do not add any + new warnings. + +Patchwork +~~~~~~~~~ + +Devicetree maintainers review patches using Patchwork, so the current status of +a patch can be checked there. For typical driver submissions, Patchwork +receives the entire patch set, but only a few patches are usually Devicetree +bindings that are reviewed by DT maintainers. + +Explanation of Patchwork statuses: + + - **New**: Not yet processed by the automation toolset. + - **Needs ACK**: Waiting for review by DT maintainers. + - **Handled Elsewhere**: Non-DT patch; not being reviewed here. + - **RFC**: Patch was likely ignored because it was an incomplete RFC. + - **Changes Requested**: Patch was reviewed and DT maintainers expect changes. + - **Accepted**: Patch was reviewed and applied by DT maintainers to their tree. + - **Not Applicable**: Patch was reviewed and is likely in good shape, with a + *Reviewed-by* or *Acked-by* tag provided, but DT maintainers expect someone + else to apply it. + +Patch Re-review and Pinging +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Due to the high volume of email traffic, Devicetree maintainers do not read +every email they receive and instead rely on Patchwork during the review +process. They also often skip patches that have already been reviewed. + +As a result, maintainers might miss: + +1. Questions about already reviewed patches. +2. Pings, for example when a patch has been reviewed by DT maintainers but has + not been picked up by subsystem maintainers. + +Such cases can be addressed by: + +1. Pinging DT maintainers on the IRC channel. +2. Dropping the DT maintainer’s *Acked-by* or *Reviewed-by* tag when sending a new + version of the patch set, together with an explanation in the patch + changelog describing why the tag was removed and what is expected from DT + maintainers. + -- cgit v1.3.1