mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-08-31 08:15:07 -04:00
df2175350e
Kumar Kartikeya Dwivedi says: ==================== Improve stack depth verification stats output Some improvements for more clarity in the stack depth verification statistics output. See commit logs for details. For example, ./test_progs -t subprogs/subprogs_alone loads prog4, which has a main program, two static subprograms, and two independently verified global subprograms. A sample run produces: verification time 1765 usec stack depth max 48 subprog 0 (prog4) main insns_self 29 insns_total 51 stack 8 subprog 1 (get_task_tgid) global insns_self 9 insns_total 9 stack 8 subprog 2 (sub4) static insns_self 15 insns_total 22 stack 8 subprog 3 (sub3) static insns_self 7 insns_total 7 stack 0 subprog 4 (sub1) global insns_self 10 insns_total 10 stack 8 processed 70 insns (limit 1000000) max_states_per_insn 0 total_states 7 peak_states 7 mark_read 0 The insns_self counts account for every processed instruction exactly once: 29 + 9 + 15 + 7 + 10 = 70 The main program and global subprograms are independent exploration roots, so their insns_total counts also account for the full processed budget: 51 + 9 + 10 = 70 Static subprogram totals provide a nested, top-down breakdown inside their root. In this example: sub4: 22 = 15 self + 7 in sub3 prog4: 51 = 29 self + 22 in sub4 The global subprogram bodies are accounted in their own root totals rather than being included in prog4 or the static callees which call them. Asynchronous callbacks start from fresh frame-zero verifier states, but the work remains part of the do_check_common() invocation for the main or global verification root under which it was scheduled. Running: ./test_progs -t verifier_subprog_insn_stats/stats_async_nested -v produces the following stats: stack depth max 0 subprog 0 (stats_async_nested) main insns_self 9 insns_total 25 stack 0 subprog 1 (stats_async_nested_schedule) static insns_self 7 insns_total 7 stack 0 subprog 2 (stats_async_outer) static insns_self 7 insns_total 7 stack 0 subprog 3 (stats_async_nested_leaf) static insns_self 2 insns_total 2 stack 0 processed 25 insns Here, 9 + 2 + 7 + 7 = 25. The main root total is the complete verifier budget for its do_check_common() invocation, including both directly and transitively scheduled asynchronous callbacks. Static subprogram and callback totals remain local to their synchronous paths. Changelog: ---------- v7 -> v8 v7: https://lore.kernel.org/bpf/20260808062601.1070988-1-memxor@gmail.com * Move the insns_total snapshot and delta for main and global roots into do_check_common() and explain why the override is needed for async subprograms. (Eduard) * Avoid splitting __msg string literals in the stack-depth stats tests. (Eduard) * Add a comment explaining why both the new per-subprogram records and the legacy one-line format are matched in veristat's parse_verif_log(). (Eduard) v6 -> v7 v6: https://lore.kernel.org/bpf/20260805011517.1717238-1-memxor@gmail.com * Rename insns_own to insns_self throughout. (Andrii) * Drop the async accounting call stack and attribute callback work to the scheduling main or global verification root using its processed-insn delta. (Eduard, Andrii) * Skip missing frames when folding instruction totals after a partial verifier state copy. (BPF CI Bot) * Use explicit callback argument operands in deterministic instruction-count tests and update tests and examples for root attribution. (BPF CI Bot) v5 -> v6 v5: https://lore.kernel.org/bpf/20260804081114.3871564-1-memxor@gmail.com * Track self and inclusive instruction counts for main, global, and static subprograms. (Andrii, Eduard) * Keep instruction subtotals path-local across verifier state copies. * Propagate async callback budget through nested scheduling chains. (Andrii) * Split per-subprogram instruction accounting into a preparatory patch. * Add deterministic selftests with exact self, total, and processed counts. v4 -> v5 v4: https://lore.kernel.org/bpf/20260803072733.191502-1-memxor@gmail.com * Change the format to combine instruction counts and stack depths into per-program records. (Andrii) * Adjust veristat for the new format while retaining support for the legacy format. * Explain why the legacy stack parsing buffer is zero-initialized. (BPF CI Bot) v3 -> v4 v3: https://lore.kernel.org/bpf/20260803031457.3115812-1-memxor@gmail.com * Read names from subprog_info directly to avoid an out-of-bounds access when func_info validation fails. (BPF CI Bot) v2 -> v3 v2: https://lore.kernel.org/bpf/20260802225209.2511758-1-memxor@gmail.com * Reuse subprog_name() to fetch subprogram names. (BPF CI Bot) v1 -> v2 v1: https://lore.kernel.org/bpf/20260801230400.850271-1-memxor@gmail.com * Use multi-line format. (Eduard) * Adjust veristat to work with old and new format. * Adjust selftest log_level without new option. (Eduard) ==================== Link: https://patch.msgid.link/20260812221925.3358041-1-memxor@gmail.com Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Linux kernel ============ The Linux kernel is the core of any Linux operating system. It manages hardware, system resources, and provides the fundamental services for all other software. Quick Start ----------- * Report a bug: See Documentation/admin-guide/reporting-issues.rst * Get the latest kernel: https://kernel.org * Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst * Join the community: https://lore.kernel.org/ Essential Documentation ----------------------- All users should be familiar with: * Building requirements: Documentation/process/changes.rst * Code of Conduct: Documentation/process/code-of-conduct.rst * License: See COPYING Documentation can be built with make htmldocs or viewed online at: https://www.kernel.org/doc/html/latest/ Who Are You? ============ Find your role below: * New Kernel Developer - Getting started with kernel development * Academic Researcher - Studying kernel internals and architecture * Security Expert - Hardening and vulnerability analysis * Backport/Maintenance Engineer - Maintaining stable kernels * System Administrator - Configuring and troubleshooting * Maintainer - Leading subsystems and reviewing patches * Hardware Vendor - Writing drivers for new hardware * Distribution Maintainer - Packaging kernels for distros * AI Coding Assistant - LLMs and AI-powered development tools For Specific Users ================== New Kernel Developer -------------------- Welcome! Start your kernel development journey here: * Getting Started: Documentation/process/development-process.rst * Your First Patch: Documentation/process/submitting-patches.rst * Coding Style: Documentation/process/coding-style.rst * Build System: Documentation/kbuild/index.rst * Development Tools: Documentation/dev-tools/index.rst * Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst * Core APIs: Documentation/core-api/index.rst Academic Researcher ------------------- Explore the kernel's architecture and internals: * Researcher Guidelines: Documentation/process/researcher-guidelines.rst * Memory Management: Documentation/mm/index.rst * Scheduler: Documentation/scheduler/index.rst * Networking Stack: Documentation/networking/index.rst * Filesystems: Documentation/filesystems/index.rst * RCU (Read-Copy Update): Documentation/RCU/index.rst * Locking Primitives: Documentation/locking/index.rst * Power Management: Documentation/power/index.rst Security Expert --------------- Security documentation and hardening guides: * Security Documentation: Documentation/security/index.rst * LSM Development: Documentation/security/lsm-development.rst * Self Protection: Documentation/security/self-protection.rst * Reporting Vulnerabilities: Documentation/process/security-bugs.rst * CVE Procedures: Documentation/process/cve.rst * Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst * Security Features: Documentation/userspace-api/seccomp_filter.rst Backport/Maintenance Engineer ----------------------------- Maintain and stabilize kernel versions: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * Backporting Guide: Documentation/process/backporting.rst * Applying Patches: Documentation/process/applying-patches.rst * Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git for Maintainers: Documentation/maintainer/configure-git.rst System Administrator -------------------- Configure, tune, and troubleshoot Linux systems: * Admin Guide: Documentation/admin-guide/index.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst * Tracing/Debugging: Documentation/trace/index.rst * Performance Security: Documentation/admin-guide/perf-security.rst * Hardware Monitoring: Documentation/hwmon/index.rst Maintainer ---------- Lead kernel subsystems and manage contributions: * Maintainer Handbook: Documentation/maintainer/index.rst * Pull Requests: Documentation/maintainer/pull-requests.rst * Managing Patches: Documentation/maintainer/modifying-patches.rst * Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst * Development Process: Documentation/process/maintainer-handbooks.rst * Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git Configuration: Documentation/maintainer/configure-git.rst Hardware Vendor --------------- Write drivers and support new hardware: * Driver API Guide: Documentation/driver-api/index.rst * Driver Model: Documentation/driver-api/driver-model/driver.rst * Device Drivers: Documentation/driver-api/infrastructure.rst * Bus Types: Documentation/driver-api/driver-model/bus.rst * Device Tree Bindings: Documentation/devicetree/bindings/ * Power Management: Documentation/driver-api/pm/index.rst * DMA API: Documentation/core-api/dma-api.rst Distribution Maintainer ----------------------- Package and distribute the kernel: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * ABI Documentation: Documentation/ABI/README * Kernel Configuration: Documentation/kbuild/kconfig.rst * Module Signing: Documentation/admin-guide/module-signing.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst AI Coding Assistant ------------------- CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and follow the AI coding assistants documentation before contributing to the Linux kernel: * Documentation/process/coding-assistants.rst This documentation contains essential requirements about licensing, attribution, and the Developer Certificate of Origin that all AI tools must comply with. Communication and Support ========================= * Mailing Lists: https://lore.kernel.org/ * IRC: #kernelnewbies on irc.oftc.net * Bugzilla: https://bugzilla.kernel.org/ * MAINTAINERS file: Lists subsystem maintainers and mailing lists * Email Clients: Documentation/process/email-clients.rst