From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- Documentation/process/coding-assistants.rst | 96 +++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) create mode 100644 Documentation/process/coding-assistants.rst (limited to 'Documentation/process/coding-assistants.rst') diff --git a/Documentation/process/coding-assistants.rst b/Documentation/process/coding-assistants.rst new file mode 100644 index 000000000..051f0d819 --- /dev/null +++ b/Documentation/process/coding-assistants.rst @@ -0,0 +1,96 @@ +.. SPDX-License-Identifier: GPL-2.0 + +.. _coding_assistants: + +AI Coding Assistants +++++++++++++++++++++ + +This document provides guidance for AI tools and developers using AI +assistance when contributing to the Linux kernel. + +AI tools helping with Linux kernel development should follow the standard +kernel development process: + +* Documentation/process/development-process.rst +* Documentation/process/coding-style.rst +* Documentation/process/submitting-patches.rst + +For guidelines on content generated by AI coding assistants see: + +* Documentation/process/generated-content.rst + +Licensing and Legal Requirements +================================ + +All contributions must comply with the kernel's licensing requirements: + +* All code must be compatible with GPL-2.0-only +* Use appropriate SPDX license identifiers +* See Documentation/process/license-rules.rst for details + +Signed-off-by and Developer Certificate of Origin +================================================= + +AI agents MUST NOT add Signed-off-by tags. Only humans can legally +certify the Developer Certificate of Origin (DCO). The human submitter +is responsible for: + +* Reviewing all AI-generated code +* Ensuring compliance with licensing requirements +* Adding their own Signed-off-by tag to certify the DCO +* Taking full responsibility for the contribution + +Attribution +=========== + +When AI tools contribute to kernel development, proper attribution +helps track the evolving role of AI in the development process. +Contributions should include an Assisted-by tag in the following format:: + + Assisted-by: LLM [TOOL1] [TOOL2] + +* ``[TOOL1] [TOOL2]`` are optional specialized analysis tools used + (e.g., coccinelle, sparse, smatch, clang-tidy) + +Basic development tools (git, gcc, make, editors) should not be listed. + +Example:: + + Assisted-by: LLM coccinelle sparse + +Procedure for finding and fixing bugs +===================================== + +When an AI assistant is used to find and fix bugs, it **MUST** follow at least +these steps: + +1. Before starting, read the whole process documentation listed above, as well + as any other document mentioned in the request. Do not rely on isolated + parts found by keyword search. +2. Note the commit ID and Locate a bug as instructed. +3. For any bug found that is not trivial, verify that it looks real by + attempting to create a reproducer to demonstrate it. Lacking it may cause + the report to be ignored, as many unverified bug reports sent to maintainers + happen to be invalid. Stop here if it finally looks wrong. +4. Write a fix for the bug. This part is not optional: except in a few very + rare cases, an AI assistant able to find a bug is able to fix it. Note that + fixes written in the same session as used to find the bug will generally + lead to better and more accurate fixes as the LLM's reasoning context + remains present. +5. Build and verify that the fix works either using the reproducer or by + re-running a complete analysis; drop any fix that doesn't work and try + another one. The fix must not add build warnings and must pass the + checkpatch.pl checks (see submitting-patches.rst). +6. Commit the working fix with a detailed message describing the problem, the + solution and a Fixes tag. Do not add a Signed-off-by tag, and add an + Assisted-by tag, as described above. +7. Identify the maintainers and lists using scripts/get_maintainer.pl. + Documentation/process/security-bugs.rst shows how to do that. +8. Indicate what could not be done. If the fix could not be built or tested, or + if no reproducer could be produced, say so explicitly: maintainers currently + waste too much time analyzing unverified reports and untested fixes. +9. Read Documentation/process/threat-model.rst to determine whether the bug is + a vulnerability or a regular bug, and leave the result to the reporter for + review (the assistant must never send anything itself). Regular bugs are + submitted as described in Documentation/process/submitting-patches.rst, + vulnerabilities as described in Documentation/process/security-bugs.rst. -- cgit v1.3.1