user/sven/linux.git/kernel/trace/trace.h, branch next/HEAD

Merge trace/for-next

2026-04-04T16:38:07Z

Merge ring-buffer/for-next

2026-04-04T16:38:06Z

tracing: Allow backup to save persistent ring buffer before it starts

2026-04-02T17:29:08Z

When the persistent ring buffer was first introduced, it did not make sense to start tracing for it on the kernel command line. That's because if there was a crash, the start of events would invalidate the events from the previous boot that had the crash. But now that there's a "backup" instance that can take a snapshot of the persistent ring buffer when boot starts, it is possible to have the persistent ring buffer start events at boot up and not lose the old events. Update the code where the boot events start after all boot time instances are created. This will allow the backup instance to copy the persistent ring buffer from the previous boot, and allow the persistent ring buffer to start tracing new events for the current boot. reserve_mem=100M:12M:trace trace_instance=boot_mapped^@trace,sched trace_instance=backup=boot_mapped The above will create a boot_mapped persistent ring buffer and enabled the scheduler events. If there's a crash, a "backup" instance will be created holding the events of the persistent ring buffer from the previous boot, while the persistent ring buffer will once again start tracing scheduler events of the current boot. Now the user doesn't have to remember to start the persistent ring buffer. It will always have the events started at each boot. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: John Stultz Link: https://patch.msgid.link/20260331163924.6ccb3896@gandalf.local.home Signed-off-by: Steven Rostedt (Google)

tracing: Remove the backup instance automatically after read

2026-04-02T17:22:30Z

Since the backup instance is readonly, after reading all data via pipe, no data is left on the instance. Thus it can be removed safely after closing all files. This also removes it if user resets the ring buffer manually via 'trace' file. Cc: Mathieu Desnoyers Link: https://patch.msgid.link/177502547711.1311542.12572973358010839400.stgit@mhiramat.tok.corp.google.com Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google)

tracing: Make the backup instance non-reusable

2026-04-02T17:20:38Z

Since there is no reason to reuse the backup instance, make it readonly (but erasable). Note that only backup instances are readonly, because other trace instances will be empty unless it is writable. Only backup instances have copy entries from the original. With this change, most of the trace control files are removed from the backup instance, including eventfs enable/filter etc. # find /sys/kernel/tracing/instances/backup/events/ | wc -l 4093 # find /sys/kernel/tracing/instances/boot_map/events/ | wc -l 9573 Cc: Mathieu Desnoyers Link: https://patch.msgid.link/177502546939.1311542.1826814401724828930.stgit@mhiramat.tok.corp.google.com Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google)

tracing: Remove duplicate latency_fsnotify() stub

2026-03-31T18:58:39Z

When the SNAPSHOT is defined but FSNOTIFY is not the latency_fsnotify() function is turned into a static inline stub. But this stub was defined in both trace.h and trace_snapshot.c causing a error in build when CONFIG_SNAPSHOT is defined but FSNOTIFY is not. The stub is not needed in trace_snapshot.c as it will be defined in trace.h, remove it from the C file. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://patch.msgid.link/20260330205859.24c0aae3@gandalf.local.home Fixes: bade44fe5462 ("tracing: Move snapshot code out of trace.c and into trace_snapshot.c") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202603310604.lGE9LDBK-lkp@intel.com/ Signed-off-by: Steven Rostedt (Google)

tracing: Append repeated boot-time tracing parameters

2026-03-31T18:52:56Z

Some tracing boot parameters already accept delimited value lists, but their __setup() handlers keep only the last instance seen at boot. Make repeated instances append to the same boot-time buffer in the format each parser already consumes. Use a shared trace_append_boot_param() helper for the ftrace filters, trace_options, and kprobe_event boot parameters. This also lets Bootconfig array values work naturally when they expand to repeated param=value entries. Before this change, only the last instance from each repeated parameter survived boot. Link: https://patch.msgid.link/20260330181103.1851230-1-atwellwea@gmail.com Signed-off-by: Wesley Atwell Signed-off-by: Steven Rostedt (Google)

Merge commit 'dc1d9408c961c1c4d4b3b99a1d9390c17e13de71' into trace/merge/core

2026-03-26T21:09:27Z

Conflicts: kernel/trace/trace.c

tracing: Move snapshot code out of trace.c and into trace_snapshot.c

2026-03-26T14:24:40Z

The trace.c file was a dumping ground for most tracing code. Start organizing it better by moving various functions out into their own files. Move all the snapshot code, including the max trace code into its own trace_snapshot.c file. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://patch.msgid.link/20260324140145.36352d6a@gandalf.local.home Signed-off-by: Steven Rostedt (Google)

tracing: Clean up access to trace_event_file from a file pointer

2026-03-24T00:16:46Z

The tracing code provides two functions event_file_file() and event_file_data() to obtain a trace_event_file pointer from a file struct. The primary method to use is event_file_file(), as it checks for the EVENT_FILE_FL_FREED flag to determine whether the event is being removed. The second function event_file_data() is an optimization for retrieving the same data when the event_mutex is still held. In the past, when removing an event directory in remove_event_file_dir(), the code set i_private to NULL for all event files and readers were expected to check for this state to recognize that the event is being removed. In the case of event_id_read(), the value was read using event_file_data() without acquiring the event_mutex. This required event_file_data() to use READ_ONCE() when retrieving the i_private data. With the introduction of eventfs, i_private is assigned when an eventfs inode is allocated and remains set throughout its lifetime. Remove the now unnecessary READ_ONCE() access to i_private in both event_file_file() and event_file_data(). Inline the access to i_private in remove_event_file_dir(), which allows event_file_data() to handle i_private solely as a trace_event_file pointer. Add a check in event_file_data() to ensure that the event_mutex is held and that file->flags doesn't have the EVENT_FILE_FL_FREED flag set. Finally, move event_file_data() immediately after event_file_code() since the latter provides a comment explaining how both functions should be used together. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Tom Zanussi Link: https://patch.msgid.link/20260219162737.314231-5-petr.pavlu@suse.com Signed-off-by: Petr Pavlu Signed-off-by: Steven Rostedt (Google)