laptop-kernel/Documentation/trace, branch master

Documentation: trace: historgram-design: Separate sched_waking histogram section heading and the following diagram

2025-10-15T10:04:01Z

[ Upstream commit 8c716e87ea33519920811338100d6d8a7fb32456 ] Section heading for sched_waking histogram is shown as normal paragraph instead due to codeblock marker for the following diagram being in the same line as the section underline. Separate them. Fixes: daceabf1b494 ("tracing/doc: Fix ascii-art in histogram-design.rst") Reviewed-by: Tom Zanussi Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Bagas Sanjaya Acked-by: Steven Rostedt (Google) Signed-off-by: Jonathan Corbet Message-ID: <20250916054202.582074-5-bagasdotme@gmail.com> Signed-off-by: Sasha Levin

Merge tag 'trace-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2025-08-01T17:29:36Z

Pull tracing updates from Steven Rostedt: - Deprecate auto-mounting tracefs to /sys/kernel/debug/tracing When tracefs was first introduced back in 2014, the directory /sys/kernel/tracing was added and is the designated location to mount tracefs. To keep backward compatibility, tracefs was auto-mounted in /sys/kernel/debug/tracing as well. All distros now mount tracefs on /sys/kernel/tracing. Having it seen in two different locations has lead to various issues and inconsistencies. The VFS folks have to also maintain debugfs_create_automount() for this single user. It's been over 10 years. Tooling and scripts should start replacing the debugfs location with the tracefs one. The reason tracefs was created in the first place was to allow access to the tracing facilities without the need to configure debugfs into the kernel. Using tracefs should now be more robust. A new config is created: CONFIG_TRACEFS_AUTOMOUNT_DEPRECATED which is default y, so that the kernel is still built with the automount. This config allows those that want to remove the automount from debugfs to do so. When tracefs is accessed from /sys/kernel/debug/tracing, the following printk is triggerd: pr_warn("NOTICE: Automounting of tracing to debugfs is deprecated and will be removed in 2030\n"); This gives users another 5 years to fix their scripts. - Use queue_rcu_work() instead of call_rcu() for freeing event filters The number of filters to be free can be many depending on the number of events within an event system. Freeing them from softirq context can potentially cause undesired latency. Use the RCU workqueue to free them instead. - Remove pointless memory barriers in latency code Memory barriers were added to some of the latency code a long time ago with the idea of "making them visible", but that's not what memory barriers are for. They are to synchronize access between different variables. There was no synchronization here making them pointless. - Remove "__attribute__()" from the type field of event format When LLVM is used to compile the kernel with CONFIG_DEBUG_INFO_BTF=y and PAHOLE_HAS_BTF_TAG=y, some of the format fields get expanded with the following: field:const char * filename; offset:24; size:8; signed:0; Turns into: field:const char __attribute__((btf_type_tag("user"))) * filename; offset:24; size:8; signed:0; This confuses parsers. Add code to strip these tags from the strings. - Add eprobe config option CONFIG_EPROBE_EVENTS Eprobes were added back in 5.15 but were only enabled when another probe was enabled (kprobe, fprobe, uprobe, etc). The eprobes had no config option of their own. Add one as they should be a separate entity. It's default y to keep with the old kernels but still has dependencies on TRACING and HAVE_REGS_AND_STACK_ACCESS_API. - Add eprobe documentation When eprobes were added back in 5.15 no documentation was added to describe them. This needs to be rectified. - Replace open coded cpumask_next_wrap() in move_to_next_cpu() - Have preemptirq_delay_run() use off-stack CPU mask - Remove obsolete comment about pelt_cfs event DECLARE_TRACE() appends "_tp" to trace events now, but the comment above pelt_cfs still mentioned appending it manually. - Remove EVENT_FILE_FL_SOFT_MODE flag The SOFT_MODE flag was required when the soft enabling and disabling of trace events was first introduced. But there was a bug with this approach as it only worked for a single instance. When multiple users required soft disabling and disabling the code was changed to have a ref count. The SOFT_MODE flag is now set iff the ref count is non zero. This is redundant and just reading the ref count is good enough. - Fix typo in comment * tag 'trace-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: Documentation: tracing: Add documentation about eprobes tracing: Have eprobes have their own config option tracing: Remove "__attribute__()" from the type field of event format tracing: Deprecate auto-mounting tracefs in debugfs tracing: Fix comment in trace_module_remove_events() tracing: Remove EVENT_FILE_FL_SOFT_MODE flag tracing: Remove pointless memory barriers tracing/sched: Remove obsolete comment on suffixes kernel: trace: preemptirq_delay_test: use offstack cpu mask tracing: Use queue_rcu_work() to free filters tracing: Replace opencoded cpumask_next_wrap() in move_to_next_cpu()

Merge tag 'docs-6.17' of git://git.lwn.net/linux

2025-07-31T15:36:51Z

Pull documentation updates from Jonathan Corbet: "It has been a relatively busy cycle for docs, especially the build system: - The Perl kernel-doc script was added to 2.3.52pre1 just after the turn of the millennium. Over the following 25 years, it accumulated a vast amount of cruft, all in a language few people want to deal with anymore. Mauro's Python replacement in 6.16 faithfully reproduced all of the cruft in the hope of avoiding regressions. Now that we have a more reasonable code base, though, we can work on cleaning it up; many of the changes this time around are toward that end. - A reorganization of the ext4 docs into the usual TOC format. - Various Chinese translations and updates. - A new script from Mauro to help with docs-build testing. - A new document for linked lists - A sweep through MAINTAINERS fixing broken GitHub git:// repository links. ...and lots of fixes and updates" * tag 'docs-6.17' of git://git.lwn.net/linux: (147 commits) scripts: add origin commit identification based on specific patterns sphinx: kernel_abi: fix performance regression with O= Documentation: core-api: entry: Replace deprecated KVM entry/exit functions docs: fault-injection: drop reference to md-faulty docs: document linked lists scripts: kdoc: make it backward-compatible with Python 3.7 docs: kernel-doc: emit warnings for ancient versions of Python Documentation/rtla: Describe exit status Documentation/rtla: Add include common_appendix.rst docs: kernel: Clarify printk_ratelimit_burst reset behavior Documentation: ioctl-number: Don't repeat macro names Documentation: ioctl-number: Shorten macros table Documentation: ioctl-number: Correct full path to papr-physical-attestation.h Documentation: ioctl-number: Extend "Include File" column width Documentation: ioctl-number: Fix linuxppc-dev mailto link overlayfs.rst: fix typos docs: kdoc: emit a warning for ancient versions of Python docs: kdoc: clean up check_sections() docs: kdoc: directly access the always-there KdocItem fields docs: kdoc: straighten up dump_declaration() ...

Merge tag 'trace-rv-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2025-07-30T23:23:12Z

Pull runtime verification updates from Steven Rostedt: - Added Linear temporal logic monitors for RT application Real-time applications may have design flaws causing them to have unexpected latency. For example, the applications may raise page faults, or may be blocked trying to take a mutex without priority inheritance. However, while attempting to implement DA monitors for these real-time rules, deterministic automaton is found to be inappropriate as the specification language. The automaton is complicated, hard to understand, and error-prone. For these cases, linear temporal logic is found to be more suitable. The LTL is more concise and intuitive. - Make printk_deferred() public The new monitors needed access to printk_deferred(). Make them visible for the entire kernel. - Add a vpanic() to allow for va_list to be passed to panic. - Add rtapp container monitor. A collection of monitors that check for common problems with real-time applications that cause unexpected latency. - Add page fault tracepoints to risc-v These tracepoints are necessary to for the RV monitor to run on risc-v. - Fix the behaviour of the rv tool with -s and idle tasks. - Allow the rv tool to gracefully terminate with SIGTERM - Adjusts dot2c not to create lines over 100 columns - Properly order nested monitors in the RV Kconfig file - Return the registration error in all DA monitor instead of 0 - Update and add new sched collection monitors Replace tss and sncid monitors with more complete sts: Not only prove that switches occur in scheduling context and scheduling needs interrupt disabled but also that each call to the scheduler disables interrupts to (optionally) switch. New monitor: nrp Preemption requires need resched which is cleared by any switch (includes a non optimal workaround for /nested/ preemptions) New monitor: sssw suspension requires setting the task to sleepable and, after the switch occurs, the task requires a wakeup to come back to runnable New monitor: opid waking and need-resched operations occur with interrupts and preemption disabled or in IRQ without explicitly disabling preemption" * tag 'trace-rv-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (48 commits) rv: Add opid per-cpu monitor rv: Add nrp and sssw per-task monitors rv: Replace tss and sncid monitors with more complete sts sched: Adapt sched tracepoints for RV task model rv: Retry when da monitor detects race conditions rv: Adjust monitor dependencies rv: Use strings in da monitors tracepoints rv: Remove trailing whitespace from tracepoint string rv: Add da_handle_start_run_event_ to per-task monitors rv: Fix wrong type cast in reactors_show() and monitor_reactor_show() rv: Fix wrong type cast in monitors_show() rv: Remove struct rv_monitor::reacting rv: Remove rv_reactor's reference counter rv: Merge struct rv_reactor_def into struct rv_reactor rv: Merge struct rv_monitor_def into struct rv_monitor rv: Remove unused field in struct rv_monitor_def rv: Return init error when registering monitors verification/rvgen: Organise Kconfig entries for nested monitors tools/dot2c: Fix generated files going over 100 column limit tools/rv: Stop gracefully also on SIGTERM ...

Documentation: tracing: Add documentation about eprobes

2025-07-30T14:38:43Z

Eprobes was added back in 5.15, but was never documented. It became a "secret" interface even though it has been a topic of several presentations. For some reason, when eprobes was added, documenting it never became a priority, until now. Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Andrew Morton Cc: Namhyung Kim Cc: Jonathan Corbet Link: https://lore.kernel.org/20250730140945.528135548@kernel.org Reviewed-by: Randy Dunlap Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google)

rv: Add opid per-cpu monitor

2025-07-28T20:47:35Z

Add a per-cpu monitor as part of the sched model: * opid: operations with preemption and irq disabled Monitor to ensure wakeup and need_resched occur with irq and preemption disabled or in irq handlers. Cc: Jonathan Corbet Cc: Masami Hiramatsu Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Tomas Glozar Cc: Juri Lelli Cc: Clark Williams Cc: John Kacur Link: https://lore.kernel.org/20250728135022.255578-10-gmonaco@redhat.com Signed-off-by: Gabriele Monaco Acked-by: Nam Cao Tested-by: Nam Cao Signed-off-by: Steven Rostedt (Google)

rv: Add nrp and sssw per-task monitors

2025-07-28T20:47:34Z

Add 2 per-task monitors as part of the sched model: * nrp: need-resched preempts Monitor to ensure preemption requires need resched. * sssw: set state sleep and wakeup Monitor to ensure sched_set_state to sleepable leads to sleeping and sleeping tasks require wakeup. Cc: Ingo Molnar Cc: Jonathan Corbet Cc: Masami Hiramatsu Cc: Tomas Glozar Cc: Juri Lelli Cc: Clark Williams Cc: John Kacur Cc: Peter Zijlstra Link: https://lore.kernel.org/20250728135022.255578-9-gmonaco@redhat.com Signed-off-by: Gabriele Monaco Acked-by: Nam Cao Tested-by: Nam Cao Signed-off-by: Steven Rostedt (Google)

rv: Replace tss and sncid monitors with more complete sts

2025-07-28T20:47:34Z

The tss monitor currently guarantees task switches can happen only while scheduling, whereas the sncid monitor enforces scheduling occurs with interrupt disabled. Replace the monitors with a more comprehensive specification which implies both but also ensures that: * each scheduler call disable interrupts to switch * each task switch happens with interrupts disabled Cc: Ingo Molnar Cc: Jonathan Corbet Cc: Masami Hiramatsu Cc: Nam Cao Cc: Tomas Glozar Cc: Juri Lelli Cc: Clark Williams Cc: John Kacur Cc: Peter Zijlstra Link: https://lore.kernel.org/20250728135022.255578-8-gmonaco@redhat.com Signed-off-by: Gabriele Monaco Signed-off-by: Steven Rostedt (Google)

verification/rvgen: Support the 'next' operator

2025-07-24T14:43:23Z

The 'next' operator is a unary operator. It is defined as: "next time, the operand must be true". Support this operator. For RV monitors, "next time" means the next invocation of ltl_validate(). Cc: John Ogness Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://lore.kernel.org/9c32cec04dd18d2e956fddd84b0e0a2503daa75a.1752239482.git.namcao@linutronix.de Signed-off-by: Nam Cao Tested-by: Gabriele Monaco Signed-off-by: Steven Rostedt (Google)

Documentation/rv: Add documentation for linear temporal logic monitors

2025-07-24T14:42:47Z

Add documents describing linear temporal logic runtime verification monitors and how to generate them using rvgen. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Gabriele Monaco Link: https://lore.kernel.org/be13719e66fd8da147d7c69d5365aa23c52b743f.1751634289.git.namcao@linutronix.de Signed-off-by: Nam Cao Signed-off-by: Steven Rostedt (Google)