user/sven/linux.git/Documentation/trace, branch v6.0.18

kprobes: kretprobe events missing on 2-core KVM guest

2023-01-04T10:26:27Z

[ Upstream commit 3b7ddab8a19aefc768f345fd3782af35b4a68d9b ] Default value of maxactive is set as num_possible_cpus() for nonpreemptable systems. For a 2-core system, only 2 kretprobe instances would be allocated in default, then these 2 instances for execve kretprobe are very likely to be used up with a pipelined command. Here's the testcase: a shell script was added to crontab, and the content of the script is: #!/bin/sh do_something_magic `tr -dc a-z < /dev/urandom | head -c 10` cron will trigger a series of program executions (4 times every hour). Then events loss would be noticed normally after 3-4 hours of testings. The issue is caused by a burst of series of execve requests. The best number of kretprobe instances could be different case by case, and should be user's duty to determine, but num_possible_cpus() as the default value is inadequate especially for systems with small number of cpus. This patch enables the logic for preemption as default, thus increases the minimum of maxactive to 10 for nonpreemptable systems. Link: https://lore.kernel.org/all/20221110081502.492289-1-wuqiang.matt@bytedance.com/ Signed-off-by: wuqiang Reviewed-by: Solar Designer Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Sasha Levin

tracing/histogram: Update document for KEYS_MAX size

2022-11-10T17:17:33Z

commit a635beeacc6d56d2b71c39e6c0103f85b53d108e upstream. After commit 4f36c2d85ced ("tracing: Increase tracing map KEYS_MAX size"), 'keys' supports up to three fields. Signed-off-by: Zheng Yejian Cc: stable@vger.kernel.org Acked-by: Masami Hiramatsu (Google) Link: https://lore.kernel.org/r/20221017103806.2479139-1-zhengyejian1@huawei.com Signed-off-by: Jonathan Corbet Signed-off-by: Greg Kroah-Hartman

coresight: docs: Fix a broken reference

2022-10-21T10:38:39Z

[ Upstream commit b99ee26a1a98a8ac0d8241224c40e6c047091d4d ] Since the commit in Fixes: tag, "coresight-cpu-debug.txt" has been turned into "arm,coresight-cpu-debug.yaml". Update the doc accordingly to avoid a 'make htmldocs' warning Fixes: 66d052047ca8 ("dt-bindings: arm: Convert CoreSight CPU debug to DT schema") Signed-off-by: Christophe JAILLET Reviewed-by: James Clark Link: https://lore.kernel.org/r/c7f864854e9e03916017712017ff59132c51c338.1659251193.git.christophe.jaillet@wanadoo.fr Signed-off-by: Mathieu Poirier Signed-off-by: Sasha Levin

Merge tag 'trace-v6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2022-08-05T16:41:12Z

Pull tracing updates from Steven Rostedt: - Runtime verification infrastructure This is the biggest change here. It introduces the runtime verification that is necessary for running Linux on safety critical systems. It allows for deterministic automata models to be inserted into the kernel that will attach to tracepoints, where the information on these tracepoints will move the model from state to state. If a state is encountered that does not belong to the model, it will then activate a given reactor, that could just inform the user or even panic the kernel (for which safety critical systems will detect and can recover from). - Two monitor models are also added: Wakeup In Preemptive (WIP - not to be confused with "work in progress"), and Wakeup While Not Running (WWNR). - Added __vstring() helper to the TRACE_EVENT() macro to replace several vsnprintf() usages that were all doing it wrong. - eprobes now can have their event autogenerated when the event name is left off. - The rest is various cleanups and fixes. * tag 'trace-v6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (50 commits) rv: Unlock on error path in rv_unregister_reactor() tracing: Use alignof__(struct {type b;}) instead of offsetof() tracing/eprobe: Show syntax error logs in error_log file scripts/tracing: Fix typo 'the the' in comment tracepoints: It is CONFIG_TRACEPOINTS not CONFIG_TRACEPOINT tracing: Use free_trace_buffer() in allocate_trace_buffers() tracing: Use a struct alignof to determine trace event field alignment rv/reactor: Add the panic reactor rv/reactor: Add the printk reactor rv/monitor: Add the wwnr monitor rv/monitor: Add the wip monitor rv/monitor: Add the wip monitor skeleton created by dot2k Documentation/rv: Add deterministic automata instrumentation documentation Documentation/rv: Add deterministic automata monitor synthesis documentation tools/rv: Add dot2k Documentation/rv: Add deterministic automaton documentation tools/rv: Add dot2c Documentation/rv: Add a basic documentation rv/include: Add instrumentation helper functions rv/include: Add deterministic automata monitor definition via C macros ...

rv/monitor: Add the wwnr monitor

2022-07-30T18:01:30Z

Per task wakeup while not running (wwnr) monitor. This model is broken, the reason is that a task can be running in the processor without being set as RUNNABLE. Think about a task about to sleep: 1: set_current_state(TASK_UNINTERRUPTIBLE); 2: schedule(); And then imagine an IRQ happening in between the lines one and two, waking the task up. BOOM, the wakeup will happen while the task is running. Q: Why do we need this model, so? A: To test the reactors. Link: https://lkml.kernel.org/r/473c0fc39967250fdebcff8b620311c11dccad30.1659052063.git.bristot@kernel.org Cc: Wim Van Sebroeck Cc: Guenter Roeck Cc: Jonathan Corbet Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Will Deacon Cc: Catalin Marinas Cc: Marco Elver Cc: Dmitry Vyukov Cc: "Paul E. McKenney" Cc: Shuah Khan Cc: Gabriele Paoloni Cc: Juri Lelli Cc: Clark Williams Cc: Tao Zhou Cc: Randy Dunlap Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google)

rv/monitor: Add the wip monitor

2022-07-30T18:01:30Z

The wakeup in preemptive (wip) monitor verifies if the wakeup events always take place with preemption disabled: | | v #==================# H preemptive H <+ #==================# | | | | preempt_disable | preempt_enable v | sched_waking +------------------+ | +--------------- | | | | | non_preemptive | | +--------------> | | -+ +------------------+ The wakeup event always takes place with preemption disabled because of the scheduler synchronization. However, because the preempt_count and its trace event are not atomic with regard to interrupts, some inconsistencies might happen. The documentation illustrates one of these cases. Link: https://lkml.kernel.org/r/c98ca678df81115fddc04921b3c79720c836b18f.1659052063.git.bristot@kernel.org Cc: Wim Van Sebroeck Cc: Guenter Roeck Cc: Jonathan Corbet Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Will Deacon Cc: Catalin Marinas Cc: Marco Elver Cc: Dmitry Vyukov Cc: "Paul E. McKenney" Cc: Shuah Khan Cc: Gabriele Paoloni Cc: Juri Lelli Cc: Clark Williams Cc: Tao Zhou Cc: Randy Dunlap Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google)

Documentation/rv: Add deterministic automata instrumentation documentation

2022-07-30T18:01:29Z

Add the da_monitor_instrumentation.rst. It describes the basics of RV monitor instrumentation. Link: https://lkml.kernel.org/r/0557d5c68e2fc252f2643c2cc5295a67e2b73277.1659052063.git.bristot@kernel.org Cc: Wim Van Sebroeck Cc: Guenter Roeck Cc: Jonathan Corbet Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Will Deacon Cc: Catalin Marinas Cc: Marco Elver Cc: Dmitry Vyukov Cc: "Paul E. McKenney" Cc: Shuah Khan Cc: Gabriele Paoloni Cc: Juri Lelli Cc: Clark Williams Cc: Tao Zhou Cc: Randy Dunlap Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google)

Documentation/rv: Add deterministic automata monitor synthesis documentation

2022-07-30T18:01:29Z

Add the da_monitor_synthesis.rst introduces some concepts behind the Deterministic Automata (DA) monitor synthesis and interface. Link: https://lkml.kernel.org/r/7873bdb7b2e5d2bc0b2eb6ca0b324af9a0ba27a0.1659052063.git.bristot@kernel.org Cc: Wim Van Sebroeck Cc: Guenter Roeck Cc: Jonathan Corbet Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Will Deacon Cc: Catalin Marinas Cc: Marco Elver Cc: Dmitry Vyukov Cc: "Paul E. McKenney" Cc: Shuah Khan Cc: Gabriele Paoloni Cc: Juri Lelli Cc: Clark Williams Cc: Tao Zhou Cc: Randy Dunlap Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google)

Documentation/rv: Add deterministic automaton documentation

2022-07-30T18:01:29Z

Add documentation about deterministic automaton and its possible representations (formal, graphic, .dot and C). Link: https://lkml.kernel.org/r/387edaed87630bd5eb37c4275045dfd229700aa6.1659052063.git.bristot@kernel.org Cc: Wim Van Sebroeck Cc: Guenter Roeck Cc: Jonathan Corbet Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Will Deacon Cc: Catalin Marinas Cc: Marco Elver Cc: Dmitry Vyukov Cc: "Paul E. McKenney" Cc: Shuah Khan Cc: Gabriele Paoloni Cc: Juri Lelli Cc: Clark Williams Cc: Tao Zhou Cc: Randy Dunlap Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google)

Documentation/rv: Add a basic documentation

2022-07-30T18:01:29Z

Add the runtime-verification.rst document, explaining the basics of RV and how to use the interface. Link: https://lkml.kernel.org/r/4be7d1a88ab1e2eb0767521e1ab52a149a154bc4.1659052063.git.bristot@kernel.org Cc: Wim Van Sebroeck Cc: Guenter Roeck Cc: Jonathan Corbet Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Will Deacon Cc: Catalin Marinas Cc: Marco Elver Cc: Dmitry Vyukov Cc: "Paul E. McKenney" Cc: Shuah Khan Cc: Gabriele Paoloni Cc: Juri Lelli Cc: Clark Williams Cc: Tao Zhou Cc: Randy Dunlap Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google)