linux.git/kernel/trace/rv, branch v6.18.21

rv: Make rtapp/pagefault monitor depends on CONFIG_MMU

2025-10-20T10:47:40+00:00

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 
Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202509260455.6Z9Vkty4-lkp@intel.com/
Cc: stable@vger.kernel.org
Reviewed-by: Gabriele Monaco 
Link: https://lore.kernel.org/r/20251002082317.973839-1-namcao@linutronix.de
Signed-off-by: Gabriele Monaco

rv: Fully convert enabled_monitors to use list_head as iterator

2025-10-20T10:47:40+00:00

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 
Closes: https://lore.kernel.org/linux-trace-kernel/20250923002004.GA2836051@ax162/
Signed-off-by: Nam Cao 
Cc: stable@vger.kernel.org
Reviewed-by: Gabriele Monaco 
Link: https://lore.kernel.org/r/20251002082235.973099-1-namcao@linutronix.de
Signed-off-by: Gabriele Monaco

rv: Fix missing mutex unlock in rv_register_monitor()

2025-09-15T06:36:35+00:00

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 
Reviewed-by: Gabriele Monaco 
Reviewed-by: Nam Cao 
Link: https://lore.kernel.org/r/20250903065112.1878330-1-zhen.ni@easystack.cn
Signed-off-by: Gabriele Monaco

rv: Fix wrong type cast in enabled_monitors_next()

2025-09-15T06:36:35+00:00

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 
Reviewed-by: Gabriele Monaco 
Link: https://lore.kernel.org/r/20250806120911.989365-1-namcao@linutronix.de
Signed-off-by: Gabriele Monaco

rv: Support systems with time64-only syscalls

2025-09-15T06:36:27+00:00

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 
Acked-by: Nam Cao 
Link: https://lore.kernel.org/r/20250804194518.97620-2-palmer@dabbelt.com
Signed-off-by: Gabriele Monaco

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

2025-08-01T17:29:36+00:00

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()

rv: Add opid per-cpu monitor

2025-07-28T20:47:35+00:00

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

2025-07-28T20:47:34+00:00

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

2025-07-28T20:47:34+00:00

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)

sched: Adapt sched tracepoints for RV task model

2025-07-28T20:47:34+00:00

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 
Cc: Peter Zijlstra 
Cc: Masami Hiramatsu 
Cc: Nam Cao 
Cc: Tomas Glozar 
Cc: Juri Lelli 
Cc: Clark Williams 
Cc: John Kacur 
Link: https://lore.kernel.org/20250728135022.255578-7-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco 
Signed-off-by: Steven Rostedt (Google)