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2026-08-04rv: Fix 32-bit build of nomiss KUnit testGabriele Monaco1-1/+1
Commit 8da2a8838365 ("rv: Add KUnit tests for some DA/HA monitors") introduced a division of a 64-bit value by 1000 in the nomiss KUnit test. This does not compile on 32-bit systems, as standard division of 64-bit values leads to an undefined reference to __udivdi3. Fix the build on 32-bit systems by using div_u64(). Fixes: 8da2a8838365 ("rv: Add KUnit tests for some DA/HA monitors") Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202608020311.hYjqOG5k-lkp@intel.com Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260803150622.322806-1-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-31rv: Add KUnit tests for some LTL monitorsGabriele Monaco7-0/+180
Validate the functionality of LTL monitors by injecting events in a controlled environment (KUnit) and expecting reactions, just like it is done in DA monitors. Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260723074534.43521-15-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-31rv: Add KUnit mock for currentGabriele Monaco5-14/+44
Some monitors do not only rely on tracepoint arguments but also on the currently executing task. This makes it more challenging to mock events in KUnit. Define wrapper functions around current, the functionality is mocked only during KUnit, an additional function call is avoided using a static branch unless any (even unrelated) KUnit test is running. Rely on a global mock_current variable that is set only by the RV KUnit tests and cleared on teardown. Unrelated KUnit tests that happen to trigger RV handlers would see it null and use current. Reviewed-by: Nam Cao <namcao@linutronix.de> Reviewed-by: Wen Yang <wen.yang@linux.dev> Link: https://lore.kernel.org/r/20260723074534.43521-14-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-31rv: Add KUnit tests for some DA/HA monitorsGabriele Monaco19-0/+622
Validate the functionality of DA monitors by injecting events in a controlled environment (KUnit) and expecting reactions. Events handlers are exported directly from the monitor source files without using system events and with dummy arguments (e.g. no real tasks). If the provided sequence of events incurs a violation, the test expects the stub version of rv_react() to be called. This testing method can validate the entire monitor implementation since it sits between the monitor and the system (in place of the tracepoints). All sorts of system and timing events can be emulated without affecting the running kernel. Handlers and monitor functions are exported as part of a struct to simplify the process of running KUnit tests from kernel modules. Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260723074534.43521-13-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-31rv: Export task monitor slot and react symbolsGabriele Monaco2-0/+3
Export rv_get_task_monitor_slot, rv_put_task_monitor_slot, and rv_react to GPL modules so they can be accessed by KUnit and future monitors built as kernel modules. Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260723074534.43521-12-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-31rv: Use generic rv_this for the rv_monitor variable in LTLGabriele Monaco2-6/+6
Align the rv_monitor variable name in LTL to the generic rv_this as it is already done for DA/HA monitors. This improves consistency and eases assumptions across model classes. Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260723074534.43521-2-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-24rv/rtapp: Add wakeup monitorNam Cao8-1/+279
Add a wakeup monitor to detect a lower-priority task waking up a higher-priority task. The rtapp/sleep monitor already detects this. However, that monitor triggers an error in the context of the wakee task and user only gets the stacktrace of that task. It is also extremely useful to get the stacktrace of the waker task, which this monitor offers. In other words, this monitor complements the rtapp/sleep monitor. Signed-off-by: Nam Cao <namcao@linutronix.de> Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/r/ba5658fa13e49ada466b84a2c211f233037180b5.1781852967.git.namcao@linutronix.de Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-24rv/rtapp/sleep: Stop monitoring kernel threadsNam Cao3-98/+46
The rtapp/sleep monitor's primary purpose is detecting common mistakes with user-space real-time design. Monitoring real-time issues with kernel threads is a bonus. However, accomodating kernel threads complicates the monitor due to the edge cases which is seen by the monitor as lower-priority task waking higher-priority task: - kthread_stop() wakes up the task in order to stop it. - The rcu thread and migration thread can be woken by any task. - The ktimerd thread is woken near the end of irq_exit_rcu(), where the preempt counter is "broken" and falsely says this is task context. This requires the monitor to use the hardirq_context flag instead of the preempt counter. Beside complicating the monitor, the final case also requires enabling CONFIG_TRACE_IRQFLAGS (so that "hardirq_context" can be used). This adds overhead to the kernel even when the monitor is not active. This may be an obstacle to enabling this monitor in distros' kernels. Furthermore, kernel threads usually are started before the monitor is enabled. Consequently, the threads' states (i.o.w. the monitor's atomic propositions for the threads) are not fully known to the monitor. As a result, the kernel threads mostly cannot be monitored. Overall, the downsides of accomodating kernel threads outweights the benefits. Thus, exclude kernel threads to simplify the monitor. Signed-off-by: Nam Cao <namcao@linutronix.de> Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/r/eec2ca5224bcdacc45b8e1eb2f0e68109e1cae7a.1781852967.git.namcao@linutronix.de Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-24rv/rtapp/sleep: Update nanosleep ruleNam Cao2-36/+28
CLOCK_REALTIME is the only clock that often is misused in real-time applications. The other clocks either are safe for real-time uses (CLOCK_TAI, CLOCK_MONOTONIC, CLOCK_BOOTTIME) or are unlikely to be misused (CLOCK_AUX, CLOCK_PROCESS_CPUTIME_ID). Update the monitor to only warn about CLOCK_REALTIME. While at it, update the out-of-sync documentation. Signed-off-by: Nam Cao <namcao@linutronix.de> Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/r/c7ceb5c6263ee8f43a2676acae669cf486b0d903.1781852967.git.namcao@linutronix.de Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-24rv/rtapp/sleep: Make the error more informative for userNam Cao2-12/+12
The rtapp/sleep monitor detects real-time tasks which go to sleep in an real-time-unsafe manner. If this happen, the monitor triggers a trace event in the sched_wakeup tracepoint's handler. However, the invoking context of that trace event is not the most informative, because of the stack trace of that event is the wakeup's code path which is not very helpful: 74.669317: rv:error_sleep: condvar[254]: violation detected ltl_validate+0x345 ([kernel.kallsyms]) handle_sched_wakeup+0x34 ([kernel.kallsyms]) ttwu_do_activate+0xff ([kernel.kallsyms]) sched_ttwu_pending+0x104 ([kernel.kallsyms]) __flush_smp_call_function_queue+0x15b ([kernel.kallsyms]) __sysvec_call_function_single+0x18 ([kernel.kallsyms]) sysvec_call_function_single+0x66 ([kernel.kallsyms]) asm_sysvec_call_function_single+0x1a ([kernel.kallsyms]) pv_native_safe_halt+0xf ([kernel.kallsyms]) default_idle+0x9 ([kernel.kallsyms]) default_idle_call+0x33 ([kernel.kallsyms]) do_idle+0x234 ([kernel.kallsyms]) cpu_startup_entry+0x24 ([kernel.kallsyms]) start_secondary+0xf8 ([kernel.kallsyms]) common_startup_64+0x13e ([kernel.kallsyms]) What would be much more valuable is the stack trace of the task itself. Instead of using the sched_wakeup tracepoint, use the sched_exit tracepoint. This makes the event happen in the task's context, making the stack trace far more informative for user: rv:error_sleep: condvar[254]: violation detected ltl_validate+0x345 ([kernel.kallsyms]) handle_sched_exit+0x39 ([kernel.kallsyms]) __schedule+0x80f ([kernel.kallsyms]) schedule+0x22 ([kernel.kallsyms]) futex_do_wait+0x33 ([kernel.kallsyms]) __futex_wait+0x8c ([kernel.kallsyms]) futex_wait+0x73 ([kernel.kallsyms]) do_futex+0xc6 ([kernel.kallsyms]) __x64_sys_futex+0x121 ([kernel.kallsyms]) do_syscall_64+0xf3 ([kernel.kallsyms]) entry_SYSCALL_64_after_hwframe+0x77 ([kernel.kallsyms]) __futex_abstimed_wait_common64+0xc6 (inlined) __futex_abstimed_wait_common+0xc6 (/usr/lib/x86_64-linux-gnu/libc.so.6) Signed-off-by: Nam Cao <namcao@linutronix.de> Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/r/d97b4b5c476e5792b6875ec9bbf8dc214f999516.1781852967.git.namcao@linutronix.de Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-23rv: Simplify task monitor slot managementLi Qiang1-13/+5
The slot array already tracks allocation and task_monitor_count duplicates that state. On an invalid second release, the old code warns but still decrements the counter, corrupting later allocations. Use the slot array as the sole source of truth. Return after warning about an unused slot, and return -EBUSY when no slot is free. Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Li Qiang <liqiang01@kylinos.cn> Link: https://lore.kernel.org/r/20260715015825.1413822-1-liqiang01@kylinos.cn Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-20rv: Simplify hybrid automata monitors's clock variablesNam Cao2-17/+3
Hybrid automata monitors's clock variables have two different representations: - The invariant representation, which is the timestamp when the invariant expires - The guard representation, which is the timestamp when the clock is last reset This dual representation makes the logic quite difficult to follow (well, at least for me). It also complicates the monitors and the generation tool, as it requires conversion back and forth between the representation. Simplify by using the clock variables for a single purpose: storing the time stamp since the clock is last reset. This also allows simplifying rvgen, which will be done in a follow-up commit. Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/c0f600dcbf3d8b487c944406851a39146f4d91fa.1781847583.git.namcao@linutronix.de Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-06-03rv: Use 0 to check preemption enabled in opidGabriele Monaco1-7/+1
Tracepoint handlers no longer run with preemption disabled by default since a46023d5616 ("tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast"), the opid monitor should now count 1 in the preemption count as preemption disabled. Change the rule for preempt_off to preempt > 0. Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260601153840.124372-11-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-06-03rv: Add automatic cleanup handlers for per-task HA monitorsGabriele Monaco3-6/+6
Hybrid automata monitors may start timers, depending on the model, these may remain active on an exiting task and cause false positives or even access freed memory. Add an enable/disable hook in the HA code, currently only populated by the per-task handler for registration and deregistration. This hooks to the sched_process_exit event and ensures the timer is stopped for every exiting task. The handler is enabled automatically but may be disabled, for instance if the monitor uses the event for another purpose (but should still manually ensure timers are stopped). Fixes: f5587d1b6ec9 ("rv: Add Hybrid Automata monitor type") Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260601153840.124372-8-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-06-03rv: Fix __user specifier usage in extract_params()Gabriele Monaco1-1/+2
The attributes variables extracted from syscalls in the helper are both defined with the __user specifier although only the actual pointer to user data should be marked. Remove the __user specifier from attr. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202604150820.Ny143u6X-lkp@intel.com Fixes: b133207deb72 ("rv: Add nomiss deadline monitor") Reviewed-by: Wen Yang <wen.yang@linux.dev> Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260601153840.124372-2-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-04-01rv: Allow epoll in rtapp-sleep monitorNam Cao2-46/+60
Since commit 0c43094f8cc9 ("eventpoll: Replace rwlock with spinlock"), epoll_wait is real-time-safe syscall for sleeping. Add epoll_wait to the list of rt-safe sleeping APIs. Signed-off-by: Nam Cao <namcao@linutronix.de> Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/r/20260401130828.3115428-1-namcao@linutronix.de Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-03-31rv: Add nomiss deadline monitorGabriele Monaco10-0/+713
Add the deadline monitors collection to validate the deadline scheduler, both for deadline tasks and servers. The currently implemented monitors are: * nomiss: validate dl entities run to completion before their deadiline Reviewed-by: Nam Cao <namcao@linutronix.de> Reviewed-by: Juri Lelli <juri.lelli@redhat.com> Link: https://lore.kernel.org/r/20260330111010.153663-13-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-03-31rv: Convert the opid monitor to a hybrid automatonGabriele Monaco5-152/+60
The opid monitor validates that wakeup and need_resched events only occur with interrupts and preemption disabled by following the preemptirq tracepoints. As reported in [1], those tracepoints might be inaccurate in some situations (e.g. NMIs). Since the monitor doesn't validate other ordering properties, remove the dependency on preemptirq tracepoints and convert the monitor to a hybrid automaton to validate the constraint during event handling. This makes the monitor more robust by also removing the workaround for interrupts missing the preemption tracepoints, which was working on PREEMPT_RT only and allows the monitor to be built on kernels without the preemptirqs tracepoints. [1] - https://lore.kernel.org/lkml/20250625120823.60600-1-gmonaco@redhat.com Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260330111010.153663-8-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-03-31rv: Add sample hybrid monitor stallGabriele Monaco7-0/+266
Add a sample monitor to showcase hybrid/timed automata. The stall monitor identifies tasks stalled for longer than a threshold and reacts when that happens. Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260330111010.153663-7-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-03-31rv: Add Hybrid Automata monitor typeGabriele Monaco2-0/+76
Deterministic automata define which events are allowed in every state, but cannot define more sophisticated constraint taking into account the system's environment (e.g. time or other states not producing events). Add the Hybrid Automata monitor type as an extension of Deterministic automata where each state transition is validating a constraint on a finite number of environment variables. Hybrid automata can be used to implement timed automata, where the environment variables are clocks. Also implement the necessary functionality to handle clock constraints (ns or jiffy granularity) on state and events. Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260330111010.153663-3-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-01-12verification/rvgen: Remove unused variable declaration from containersGabriele Monaco2-4/+0
The monitor container source files contained a declaration and a definition for the rv_monitor variable. The former is superfluous and can be removed. Remove the variable declaration from the template as well as the existing monitor containers. Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20251126104241.291258-9-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-01-12verification/dot2c: Remove superfluous enum assignment and add last commaGabriele Monaco10-82/+82
The header files generated by dot2c currently create enums for states and events assigning the first element to 0. This is superfluous as it happens automatically if no value is specified. Also it doesn't add a comma to the last enum elements, which slightly complicates the diff if states or events are added. Remove the assignment to 0 and add a comma to last elements, this simplifies the logic for the code generator. Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20251126104241.291258-8-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-01-12rv: Refactor da_monitor to minimise macrosGabriele Monaco20-162/+162
The da_monitor helper functions are generated from macros of the type: DECLARE_DA_FUNCTION(name, type) \ static void da_func_x_##name(type arg) {} \ static void da_func_y_##name(type arg) {} \ This is good to minimise code duplication but the long macros made of skipped end of lines is rather hard to parse. Since functions are static, the advantage of naming them differently for each monitor is minimal. Refactor the da_monitor.h file to minimise macros, instead of declaring functions from macros, we simply declare them with the same name for all monitors (e.g. da_func_x) and for any remaining reference to the monitor name (e.g. tracepoints, enums, global variables) we use the CONCATENATE macro. In this way the file is much easier to maintain while keeping the same generality. Functions depending on the monitor types are now conditionally compiled according to the value of RV_MON_TYPE, which must be defined in the monitor source. The monitor type can be specified as in the original implementation, although it's best to keep the default implementation (unsigned char) as not all parts of code support larger data types, and likely there's no need. We keep the empty macro definitions to ease review of this change with diff tools, but cleanup is required. Also adapt existing monitors to keep the build working. Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20251126104241.291258-2-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2025-12-02rv: Convert to use __freeNam Cao3-57/+44
Convert to use __free to tidy up the code. Signed-off-by: Nam Cao <namcao@linutronix.de> Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/r/62854e2fcb8f8dd2180a98a9700702dcf89a6980.1763370183.git.namcao@linutronix.de Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2025-12-02rv: Convert to use lock guardNam Cao2-45/+20
Convert to use lock guard to tidy up the code. Signed-off-by: Nam Cao <namcao@linutronix.de> Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/r/dbefeb868093c40d4b29fd6b57294a6aa011b719.1763370183.git.namcao@linutronix.de Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2025-11-11rv: Add explicit lockdep context for reactorsThomas Weißschuh1-0/+4
Reactors can be called from any context through tracepoints. When developing reactors care needs to be taken to only call APIs which are safe. As the tracepoints used during testing may not actually be called from restrictive contexts lockdep may not be helpful. Add explicit overrides to help lockdep find invalid code patterns. The usage of LD_WAIT_FREE will trigger lockdep warnings in the panic reactor. These are indeed valid warnings but they are out of scope for RV and will instead be fixed by the printk subsystem. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Acked-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20251014-rv-lockdep-v1-3-0b9e51919ea8@linutronix.de Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2025-11-11rv: Make rv_reacting_on() staticThomas Weißschuh1-1/+1
There are no external users left. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Link: https://lore.kernel.org/r/20251014-rv-lockdep-v1-2-0b9e51919ea8@linutronix.de Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2025-11-11rv: Pass va_list to reactorsThomas Weißschuh3-11/+17
The only thing the reactors can do with the passed in varargs is to convert it into a va_list. Do that in a central helper instead. It simplifies the reactors, removes some hairy macro-generated code and introduces a convenient hook point to modify reactor behavior. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Link: https://lore.kernel.org/r/20251014-rv-lockdep-v1-1-0b9e51919ea8@linutronix.de Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2025-10-20rv: Make rtapp/pagefault monitor depends on CONFIG_MMUNam Cao1-0/+1
There is no page fault without MMU. Compiling the rtapp/pagefault monitor without CONFIG_MMU fails as page fault tracepoints' definitions are not available. Make rtapp/pagefault monitor depends on CONFIG_MMU. Fixes: 9162620eb604 ("rv: Add rtapp_pagefault monitor") Signed-off-by: Nam Cao <namcao@linutronix.de> Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202509260455.6Z9Vkty4-lkp@intel.com/ Cc: stable@vger.kernel.org Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/r/20251002082317.973839-1-namcao@linutronix.de Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2025-10-20rv: Fully convert enabled_monitors to use list_head as iteratorNam Cao1-6/+6
The callbacks in enabled_monitors_seq_ops are inconsistent. Some treat the iterator as struct rv_monitor *, while others treat the iterator as struct list_head *. This causes a wrong type cast and crashes the system as reported by Nathan. Convert everything to use struct list_head * as iterator. This also makes enabled_monitors consistent with available_monitors. Fixes: de090d1ccae1 ("rv: Fix wrong type cast in enabled_monitors_next()") Reported-by: Nathan Chancellor <nathan@kernel.org> Closes: https://lore.kernel.org/linux-trace-kernel/20250923002004.GA2836051@ax162/ Signed-off-by: Nam Cao <namcao@linutronix.de> Cc: stable@vger.kernel.org Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/r/20251002082235.973099-1-namcao@linutronix.de Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2025-09-15rv: Fix missing mutex unlock in rv_register_monitor()Zhen Ni1-1/+1
If create_monitor_dir() fails, the function returns directly without releasing rv_interface_lock. This leaves the mutex locked and causes subsequent monitor registration attempts to deadlock. Fix it by making the error path jump to out_unlock, ensuring that the mutex is always released before returning. Fixes: 24cbfe18d55a ("rv: Merge struct rv_monitor_def into struct rv_monitor") Signed-off-by: Zhen Ni <zhen.ni@easystack.cn> Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20250903065112.1878330-1-zhen.ni@easystack.cn Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2025-09-15rv: Fix wrong type cast in enabled_monitors_next()Nam Cao1-1/+1
Argument 'p' of enabled_monitors_next() is not a pointer to struct rv_monitor, it is actually a pointer to the list_head inside struct rv_monitor. Therefore it is wrong to cast 'p' to struct rv_monitor *. This wrong type cast has been there since the beginning. But it still worked because the list_head was the first field in struct rv_monitor_def. This is no longer true since commit 24cbfe18d55a ("rv: Merge struct rv_monitor_def into struct rv_monitor") moved the list_head, and this wrong type cast became a functional problem. Properly use container_of() instead. Fixes: 24cbfe18d55a ("rv: Merge struct rv_monitor_def into struct rv_monitor") Signed-off-by: Nam Cao <namcao@linutronix.de> Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/r/20250806120911.989365-1-namcao@linutronix.de Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2025-09-15rv: Support systems with time64-only syscallsPalmer Dabbelt1-0/+4
Some systems (like 32-bit RISC-V) only have the 64-bit time_t versions of syscalls. So handle the 32-bit time_t version of those being undefined. Fixes: f74f8bb246cf ("rv: Add rtapp_sleep monitor") Closes: https://lore.kernel.org/oe-kbuild-all/202508160204.SsFyNfo6-lkp@intel.com Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com> Acked-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20250804194518.97620-2-palmer@dabbelt.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2025-08-01Merge tag 'trace-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-traceLinus Torvalds1-6/+0
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()
2025-07-28rv: Add opid per-cpu monitorGabriele Monaco7-0/+309
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 <corbet@lwn.net> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tomas Glozar <tglozar@redhat.com> Cc: Juri Lelli <jlelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Link: https://lore.kernel.org/20250728135022.255578-10-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com> Acked-by: Nam Cao <namcao@linutronix.de> Tested-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-28rv: Add nrp and sssw per-task monitorsGabriele Monaco12-0/+502
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 <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Tomas Glozar <tglozar@redhat.com> Cc: Juri Lelli <jlelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/20250728135022.255578-9-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com> Acked-by: Nam Cao <namcao@linutronix.de> Tested-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-28rv: Replace tss and sncid monitors with more complete stsGabriele Monaco14-335/+299
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 <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nam Cao <namcao@linutronix.de> Cc: Tomas Glozar <tglozar@redhat.com> Cc: Juri Lelli <jlelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/20250728135022.255578-8-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-28sched: Adapt sched tracepoints for RV task modelGabriele Monaco5-10/+10
Add the following tracepoint: * sched_set_need_resched(tsk, cpu, tif) Called when a task is set the need resched [lazy] flag Remove the unused ip parameter from sched_entry and sched_exit and alter sched_entry to have a value of preempt consistent with the one used in sched_switch. Also adapt all monitors using sched_{entry,exit} to avoid breaking build. These tracepoints are useful to describe the Linux task model and are adapted from the patches by Daniel Bristot de Oliveira (https://bristot.me/linux-task-model/). Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nam Cao <namcao@linutronix.de> Cc: Tomas Glozar <tglozar@redhat.com> Cc: Juri Lelli <jlelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Link: https://lore.kernel.org/20250728135022.255578-7-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-28rv: Retry when da monitor detects race conditionsGabriele Monaco2-0/+29
DA monitor can be accessed from multiple cores simultaneously, this is likely, for instance when dealing with per-task monitors reacting on events that do not always occur on the CPU where the task is running. This can cause race conditions where two events change the next state and we see inconsistent values. E.g.: [62] event_srs: 27: sleepable x sched_wakeup -> running (final) [63] event_srs: 27: sleepable x sched_set_state_sleepable -> sleepable [63] error_srs: 27: event sched_switch_suspend not expected in the state running In this case the monitor fails because the event on CPU 62 wins against the one on CPU 63, although the correct state should have been sleepable, since the task get suspended. Detect if the current state was modified by using try_cmpxchg while storing the next value. If it was, try again reading the current state. After a maximum number of failed retries, react by calling a special tracepoint, print on the console and reset the monitor. Remove the functions da_monitor_curr_state() and da_monitor_set_state() as they only hide the underlying implementation in this case. Monitors where this type of condition can occur must be able to account for racing events in any possible order, as we cannot know the winner. Cc: Ingo Molnar <mingo@redhat.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Tomas Glozar <tglozar@redhat.com> Cc: Juri Lelli <jlelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/20250728135022.255578-6-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com> Reviewed-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-28rv: Adjust monitor dependenciesGabriele Monaco4-4/+4
RV monitors relying on the preemptirqs tracepoints are set as dependent on PREEMPT_TRACER and IRQSOFF_TRACER. In fact, those configurations do enable the tracepoints but are not the minimal configurations enabling them, which are TRACE_PREEMPT_TOGGLE and TRACE_IRQFLAGS (not selectable manually). Set TRACE_PREEMPT_TOGGLE and TRACE_IRQFLAGS as dependencies for monitors. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tomas Glozar <tglozar@redhat.com> Cc: Juri Lelli <jlelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Link: https://lore.kernel.org/20250728135022.255578-5-gmonaco@redhat.com Fixes: fbe6c09b7eb4 ("rv: Add scpd, snep and sncid per-cpu monitors") Acked-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-28rv: Use strings in da monitors tracepointsGabriele Monaco1-38/+38
Using DA monitors tracepoints with KASAN enabled triggers the following warning: BUG: KASAN: global-out-of-bounds in do_trace_event_raw_event_event_da_monitor+0xd6/0x1a0 Read of size 32 at addr ffffffffaada8980 by task ... Call Trace: <TASK> [...] do_trace_event_raw_event_event_da_monitor+0xd6/0x1a0 ? __pfx_do_trace_event_raw_event_event_da_monitor+0x10/0x10 ? trace_event_sncid+0x83/0x200 trace_event_sncid+0x163/0x200 [...] The buggy address belongs to the variable: automaton_snep+0x4e0/0x5e0 This is caused by the tracepoints reading 32 bytes __array instead of __string from the automata definition. Such strings are literals and reading 32 bytes ends up in out of bound memory accesses (e.g. the next automaton's data in this case). The error is harmless as, while printing the string, we stop at the null terminator, but it should still be fixed. Use the __string facilities while defining the tracepoints to avoid reading out of bound memory. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tomas Glozar <tglozar@redhat.com> Cc: Juri Lelli <jlelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Link: https://lore.kernel.org/20250728135022.255578-4-gmonaco@redhat.com Fixes: 792575348ff7 ("rv/include: Add deterministic automata monitor definition via C macros") Reviewed-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-28rv: Remove trailing whitespace from tracepoint stringGabriele Monaco1-4/+4
RV event tracepoints print a line with the format: "event_xyz: S0 x event -> S1 " "event_xyz: S1 x event -> S0 (final)" While printing an event leading to a non-final state, the line has a trailing white space (visible above before the closing "). Adapt the format string not to print the trailing whitespace if we are not printing "(final)". Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tomas Glozar <tglozar@redhat.com> Cc: Juri Lelli <jlelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Link: https://lore.kernel.org/20250728135022.255578-3-gmonaco@redhat.com Reviewed-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-28rv: Fix wrong type cast in reactors_show() and monitor_reactor_show()Nam Cao1-2/+2
Argument 'p' of reactors_show() and monitor_reactor_show() is not a pointer to struct rv_reactor, it is actually a pointer to the list_head inside struct rv_reactor. Therefore it's wrong to cast 'p' to struct rv_reactor *. This wrong type cast has been there since the beginning. But it still worked because the list_head was the first field in struct rv_reactor_def. This is no longer true since commit 3d3c376118b5 ("rv: Merge struct rv_reactor_def into struct rv_reactor") moved the list_head, and this wrong type cast became a functional problem. Properly use container_of() instead. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/b4febbd6844311209e4c8768b65d508b81bd8c9b.1753625621.git.namcao@linutronix.de Fixes: 3d3c376118b5 ("rv: Merge struct rv_reactor_def into struct rv_reactor") Signed-off-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-28rv: Fix wrong type cast in monitors_show()Nam Cao1-1/+1
Argument 'p' of monitors_show() is not a pointer to struct rv_monitor, it is actually a pointer to the list_head inside struct rv_monitor. Therefore it is wrong to cast 'p' to struct rv_monitor *. This wrong type cast has been there since the beginning. But it still worked because the list_head was the first field in struct rv_monitor_def. This is no longer true since commit 24cbfe18d55a ("rv: Merge struct rv_monitor_def into struct rv_monitor") moved the list_head, and this wrong type cast became a functional problem. Properly use container_of() instead. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/35e49e97696007919ceacf73796487a2e15a3d02.1753625621.git.namcao@linutronix.de Fixes: 24cbfe18d55a ("rv: Merge struct rv_monitor_def into struct rv_monitor") Signed-off-by: Nam Cao <namcao@linutronix.de> Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-25rv: Remove struct rv_monitor::reactingNam Cao1-14/+5
The field 'reacting' in struct rv_monitor is set but never used. Delete it. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/a6c16f845d2f1a09c4d0934ab83f3cb14478a71d.1753378331.git.namcao@linutronix.de Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-25rv: Remove rv_reactor's reference counterNam Cao3-38/+2
rv_reactor has a reference counter to ensure it is not removed while monitors are still using it. However, this is futile, as __exit functions are not expected to fail and will proceed normally despite rv_unregister_reactor() returning an error. At the moment, reactors do not support being built as modules, therefore they are never removed and the reference counters are not necessary. If we support building RV reactors as modules in the future, kernel module's centralized facilities such as try_module_get(), module_put() or MODULE_SOFTDEP should be used instead of this custom implementation. Remove this reference counter. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/bb946398436a5e17fb0f5b842ef3313c02291852.1753378331.git.namcao@linutronix.de Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-25rv: Merge struct rv_reactor_def into struct rv_reactorNam Cao2-62/+39
Each struct rv_reactor has a unique struct rv_reactor_def associated with it. struct rv_reactor is statically allocated, while struct rv_reactor_def is dynamically allocated. This makes the code more complicated than it should be: - Lookup is required to get the associated rv_reactor_def from rv_reactor - Dynamic memory allocation is required for rv_reactor_def. This is harder to get right compared to static memory. For instance, there is an existing mistake: rv_unregister_reactor() does not free the memory allocated by rv_register_reactor(). This is fortunately not a real memory leak problem as rv_unregister_reactor() is never called. Simplify and merge rv_reactor_def into rv_reactor. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/71cb91c86cd40df5b8c492b788787f2a73c3eaa3.1753378331.git.namcao@linutronix.de Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-25rv: Merge struct rv_monitor_def into struct rv_monitorNam Cao3-168/+132
Each struct rv_monitor has a unique struct rv_monitor_def associated with it. struct rv_monitor is statically allocated, while struct rv_monitor_def is dynamically allocated. This makes the code more complicated than it should be: - Lookup is required to get the associated rv_monitor_def from rv_monitor - Dynamic memory allocation is required for rv_monitor_def. This is harder to get right compared to static memory. For instance, there is an existing mistake: rv_unregister_monitor() does not free the memory allocated by rv_register_monitor(). This is fortunately not a real memory leak problem, as rv_unregister_monitor() is never called. Simplify and merge rv_monitor_def into rv_monitor. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/194449c00f87945c207aab4c96920c75796a4f53.1753378331.git.namcao@linutronix.de Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-25rv: Remove unused field in struct rv_monitor_defNam Cao1-1/+0
rv_monitor_def::task_monitor is not used. Delete it. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/502d94f2696435690a2b1fdbe80a9e56c96fcabf.1753378331.git.namcao@linutronix.de Reviewed-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-24rv: Return init error when registering monitorsGabriele Monaco9-18/+9
Monitors generated with dot2k have their registration function (the one called during monitor initialisation) return always 0, even if the registration failed on RV side. This can hide potential errors. Return the value returned by the RV register function. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Tomas Glozar <tglozar@redhat.com> Cc: Juri Lelli <jlelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Link: https://lore.kernel.org/20250723161240.194860-6-gmonaco@redhat.com Reviewed-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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