linux-toradex.git/kernel/trace/trace_events.c, branch v7.0-rc1

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using

    git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook

tracing: Wake up poll waiters for hist files when removing an event

2026-02-19T20:25:11+00:00

The event_hist_poll() function attempts to verify whether an event file is
being removed, but this check may not occur or could be unnecessarily
delayed. This happens because hist_poll_wakeup() is currently invoked only
from event_hist_trigger() when a hist command is triggered. If the event
file is being removed, no associated hist command will be triggered and a
waiter will be woken up only after an unrelated hist command is triggered.

Fix the issue by adding a call to hist_poll_wakeup() in
remove_event_file_dir() after setting the EVENT_FILE_FL_FREED flag. This
ensures that a task polling on a hist file is woken up and receives
EPOLLERR.

Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers 
Cc: Tom Zanussi 
Acked-by: Masami Hiramatsu (Google) 
Link: https://patch.msgid.link/20260219162737.314231-3-petr.pavlu@suse.com
Fixes: 1bd13edbbed6 ("tracing/hist: Add poll(POLLIN) support on hist file")
Signed-off-by: Petr Pavlu 
Signed-off-by: Steven Rostedt (Google)

tracing: Make tracing_disabled global for tracing system

2026-02-09T02:01:11+00:00

The tracing_disabled variable is set to one on boot up to prevent some
parts of tracing to access the tracing infrastructure before it is set up.
It also can be set after boot if an anomaly is discovered.

It is currently a static variable in trace.c and can be accessed via a
function call trace_is_disabled(). There's really no reason to use a
function call as the tracing subsystem should be able to access it
directly.

By making the variable accessed directly, code can be moved out of trace.c
without adding overhead of a function call to see if tracing is disabled
or not.

Make tracing_disabled global and remove the tracing_is_disabled() helper
function. Also add some "unlikely()"s around tracing_disabled where it's
checked in hot paths.

Cc: Masami Hiramatsu 
Cc: Mark Rutland 
Cc: Mathieu Desnoyers 
Cc: Andrew Morton 
Link: https://patch.msgid.link/20260208032449.483690153@kernel.org
Signed-off-by: Steven Rostedt (Google)

tracing: Add kerneldoc to trace_event_buffer_reserve()

2026-01-30T15:44:38+00:00

Add a appropriate kerneldoc to trace_event_buffer_reserve() to make it
easier to understand how that function is used.

Cc: Masami Hiramatsu 
Cc: Mathieu Desnoyers 
Link: https://patch.msgid.link/20260130103745.1126e4af@gandalf.local.home
Signed-off-by: Steven Rostedt (Google)

tracing: Remove duplicate ENABLE_EVENT_STR and DISABLE_EVENT_STR macros

2026-01-29T02:01:10+00:00

The macros ENABLE_EVENT_STR and DISABLE_EVENT_STR were added to trace.h so
that more than one file can have access to them, but was never removed
from their original location. Remove the duplicates.

Cc: Masami Hiramatsu 
Cc: Mathieu Desnoyers 
Cc: Tom Zanussi 
Link: https://patch.msgid.link/20260126130037.4ba201f9@gandalf.local.home
Fixes: d0bad49bb0a09 ("tracing: Add enable_hist/disable_hist triggers")
Signed-off-by: Steven Rostedt (Google)

tracing: Have show_event_trigger/filter format a bit more in columns

2026-01-26T22:45:06+00:00

By doing:

 # trace-cmd sqlhist -e -n futex_wait select TIMESTAMP_DELTA_USECS as lat from sys_enter_futex as start join sys_exit_futex as end on start.common_pid = end.common_pid

and

 # trace-cmd start -e futex_wait -f 'lat > 100' -e page_pool_state_release -f 'pfn == 1'

The output of the show_event_trigger and show_event_filter files are well
aligned because of the inconsistent 'tab' spacing:

 ~# cat /sys/kernel/tracing/show_event_triggers
syscalls:sys_exit_futex	hist:keys=common_pid:vals=hitcount:__lat_12046_2=common_timestamp.usecs-$__arg_12046_1:sort=hitcount:size=2048:clock=global:onmatch(syscalls.sys_enter_futex).trace(futex_wait,$__lat_12046_2) [active]
syscalls:sys_enter_futex	hist:keys=common_pid:vals=hitcount:__arg_12046_1=common_timestamp.usecs:sort=hitcount:size=2048:clock=global [active]

 ~# cat /sys/kernel/tracing/show_event_filters
synthetic:futex_wait	(lat > 100)
page_pool:page_pool_state_release	(pfn == 1)

This makes it not so easy to read. Instead, force the spacing to be at
least 32 bytes from the beginning (one space if the system:event is longer
than 30 bytes):

 ~# cat /sys/kernel/tracing/show_event_triggers
syscalls:sys_exit_futex          hist:keys=common_pid:vals=hitcount:__lat_8125_2=common_timestamp.usecs-$__arg_8125_1:sort=hitcount:size=2048:clock=global:onmatch(syscalls.sys_enter_futex).trace(futex_wait,$__lat_8125_2) [active]
syscalls:sys_enter_futex         hist:keys=common_pid:vals=hitcount:__arg_8125_1=common_timestamp.usecs:sort=hitcount:size=2048:clock=global [active]

 ~# cat /sys/kernel/tracing/show_event_filters
synthetic:futex_wait             (lat > 100)
page_pool:page_pool_state_release (pfn == 1)

Cc: Mathieu Desnoyers 
Link: https://patch.msgid.link/20260112153408.18373e73@gandalf.local.home
Reviewed-by: Aaron Tomlin 
Acked-by: Masami Hiramatsu (Google) 
Signed-off-by: Steven Rostedt (Google)

tracing: Add show_event_triggers to expose active event triggers

2026-01-26T22:44:24+00:00

To audit active event triggers, userspace currently must traverse the
events/ directory and read each individual trigger file. This is
cumbersome for system-wide auditing or debugging.

Introduce "show_event_triggers" at the trace root directory. This file
displays all events that currently have one or more triggers applied,
alongside the trigger configuration, in a consolidated
system:event [tab] trigger format.

The implementation leverages the existing trace_event_file iterators
and uses the trigger's own print() operation to ensure output
consistency with the per-event trigger files.

Link: https://patch.msgid.link/20260105142939.2655342-3-atomlin@atomlin.com
Signed-off-by: Aaron Tomlin 
Signed-off-by: Steven Rostedt (Google)

tracing: Add show_event_filters to expose active event filters

2026-01-26T22:44:15+00:00

Currently, to audit active Ftrace event filters, userspace must
recursively traverse the events/ directory and read each individual
filter file. This is inefficient for monitoring tools and debugging.

Introduce "show_event_filters" at the trace root directory. This file
displays all events that currently have a filter applied, alongside the
actual filter string, in a consolidated system:event [tab] filter
format.

The implementation reuses the existing trace_event_file iterators to
ensure atomic traversal of the event list and utilises guard(rcu)() for
automatic, scope-based protection when accessing volatile filter
strings.

Link: https://patch.msgid.link/20260105142939.2655342-2-atomlin@atomlin.com
Signed-off-by: Aaron Tomlin 
Signed-off-by: Steven Rostedt (Google)

tracing: Drop unneeded assignment to soft_mode

2026-01-07T19:52:22+00:00

soft_mode is not read in the enable case, so drop the assignment.
Drop also the comment text that refers to the assignment and realign
the comment.

Cc: "Paul E . McKenney" 
Cc: Gabriele Paoloni 
Cc: Masami Hiramatsu 
Cc: Mathieu Desnoyers 
Link: https://patch.msgid.link/20251226110531.4129794-1-Julia.Lawall@inria.fr
Signed-off-by: Julia Lawall 
Signed-off-by: Steven Rostedt (Google)