tracing: Fix TASK_COMM_LEN in trace event format file

After commit 3087c61ed2c4 ("tools/testing/selftests/bpf: replace open-coded 16 with TASK_COMM_LEN"),
the content of the format file under
/sys/k

tracing: Fix TASK_COMM_LEN in trace event format file

After commit 3087c61ed2c4 ("tools/testing/selftests/bpf: replace open-coded 16 with TASK_COMM_LEN"),
the content of the format file under
/sys/kernel/tracing/events/task/task_newtask was changed from
field:char comm[16]; offset:12; size:16; signed:0;
to
field:char comm[TASK_COMM_LEN]; offset:12; size:16; signed:0;

John reported that this change breaks older versions of perfetto.
Then Mathieu pointed out that this behavioral change was caused by the
use of __stringify(_len), which happens to work on macros, but not on enum
labels. And he also gave the suggestion on how to fix it:
:One possible solution to make this more robust would be to extend
:struct trace_event_fields with one more field that indicates the length
:of an array as an actual integer, without storing it in its stringified
:form in the type, and do the formatting in f_show where it belongs.

The result as follows after this change,
$ cat /sys/kernel/tracing/events/task/task_newtask/format
field:char comm[16]; offset:12; size:16; signed:0;

Link: https://lore.kernel.org/lkml/Y+QaZtz55LIirsUO@google.com/
Link: https://lore.kernel.org/linux-trace-kernel/20230210155921.4610-1-laoar.shao@gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20230212151303.12353-1-laoar.shao@gmail.com

Cc: stable@vger.kernel.org
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Kajetan Puchalski <kajetan.puchalski@arm.com>
CC: Qais Yousef <qyousef@layalina.io>
Fixes: 3087c61ed2c4 ("tools/testing/selftests/bpf: replace open-coded 16 with TASK_COMM_LEN")
Reported-by: John Stultz <jstultz@google.com>
Debugged-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

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Merge tag 'v6.2-rc7' into media_tree

Linux 6.2-rc7

* tag 'v6.2-rc7': (1549 commits)
Linux 6.2-rc7
fbcon: Check font dimension limits
efi: fix potential NULL deref in efi_mem_reserve_persisten

Merge tag 'v6.2-rc7' into media_tree

Linux 6.2-rc7

* tag 'v6.2-rc7': (1549 commits)
Linux 6.2-rc7
fbcon: Check font dimension limits
efi: fix potential NULL deref in efi_mem_reserve_persistent
kernel/irq/irqdomain.c: fix memory leak with using debugfs_lookup()
HV: hv_balloon: fix memory leak with using debugfs_lookup()
mtk_sgmii: enable PCS polling to allow SFP work
net: mediatek: sgmii: fix duplex configuration
net: mediatek: sgmii: ensure the SGMII PHY is powered down on configuration
MAINTAINERS: update SCTP maintainers
MAINTAINERS: ipv6: retire Hideaki Yoshifuji
mailmap: add John Crispin's entry
MAINTAINERS: bonding: move Veaceslav Falico to CREDITS
net: openvswitch: fix flow memory leak in ovs_flow_cmd_new
net: ethernet: mtk_eth_soc: disable hardware DSA untagging for second MAC
virtio-net: Keep stop() to follow mirror sequence of open()
efi: Accept version 2 of memory attributes table
ceph: blocklist the kclient when receiving corrupted snap trace
ceph: move mount state enum to super.h
selftests: net: udpgso_bench_tx: Cater for pending datagrams zerocopy benchmarking
selftests: net: udpgso_bench: Fix racing bug between the rx/tx programs
...

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tracing: Add enabling of events to boot instances

Add the format of:

trace_instance=foo,sched:sched_switch,irq_handler_entry,initcall

That will create the "foo" instance and enable the sched_swi

tracing: Add enabling of events to boot instances

Add the format of:

trace_instance=foo,sched:sched_switch,irq_handler_entry,initcall

That will create the "foo" instance and enable the sched_switch event
(here were the "sched" system is explicitly specified), the
irq_handler_entry event, and all events under the system initcall.

Link: https://lkml.kernel.org/r/20230207173026.386114535@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

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Merge remote-tracking branch 'torvalds/master' into perf/core

To sync with libbpf, etc.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Merge 6.2-rc7 into tty-next

We need the tty/serial fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge 6.2-rc7 into char-misc-next

We need the char-misc driver fixes in here as other patches depend on
them.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge 6.2-rc7 into usb-next

We need the USB fixes in here, and this resolves a merge conflict with
the i915 driver as reported in linux-next

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundatio

Merge 6.2-rc7 into usb-next

We need the USB fixes in here, and this resolves a merge conflict with
the i915 driver as reported in linux-next

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

net/core/gro.c
7d2c89b32587 ("skb: Do mix page pool and page referenced frags in GRO")
b1a78b9b9886 ("net: add support for ipv4 big

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

net/core/gro.c
7d2c89b32587 ("skb: Do mix page pool and page referenced frags in GRO")
b1a78b9b9886 ("net: add support for ipv4 big tcp")
https://lore.kernel.org/all/20230203094454.5766f160@canb.auug.org.au/

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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Merge tag 'v6.2-rc6' into sched/core, to pick up fixes

Pick up fixes before merging another batch of cpuidle updates.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge drm/drm-next into drm-misc-next

Backmerging to get v6.2-rc6.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge v6.2-rc6 into drm-next

Due to holidays we started -next with more -fixes in-flight than
usual, and people have been asking where they are. Backmerge to get
things better in sync.

Conflicts:
-

Merge v6.2-rc6 into drm-next

Due to holidays we started -next with more -fixes in-flight than
usual, and people have been asking where they are. Backmerge to get
things better in sync.

Conflicts:
- Tiny conflict in drm_fbdev_generic.c between variable rename and
missing error handling that got added.
- Conflict in drm_fb_helper.c between the added call to vgaswitcheroo
in drm_fb_helper_single_fb_probe and a refactor patch that extracted
lots of helpers and incidentally removed the dev local variable.
Readd it to make things compile.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

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Merge tag 'trace-v6.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

- Fix filter memory leak by calling ftrace_free_filter()

- I

Merge tag 'trace-v6.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

- Fix filter memory leak by calling ftrace_free_filter()

- Initialize trace_printk() earlier so that ftrace_dump_on_oops shows
data on early crashes.

- Update the outdated instructions in scripts/tracing/ftrace-bisect.sh

- Add lockdep_is_held() to fix lockdep warning

- Add allocation failure check in create_hist_field()

- Don't initialize pointer that gets set right away in enabled_monitors_write()

- Update MAINTAINER entries

- Fix help messages in Kconfigs

- Fix kernel-doc header for update_preds()

* tag 'trace-v6.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
bootconfig: Update MAINTAINERS file to add tree and mailing list
rv: remove redundant initialization of pointer ptr
ftrace: Maintain samples/ftrace
tracing/filter: fix kernel-doc warnings
lib: Kconfig: fix spellos
trace_events_hist: add check for return value of 'create_hist_field'
tracing/osnoise: Use built-in RCU list checking
tracing: Kconfig: Fix spelling/grammar/punctuation
ftrace/scripts: Update the instructions for ftrace-bisect.sh
tracing: Make sure trace_printk() can output as soon as it can be used
ftrace: Export ftrace_free_filter() to modules

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tracing: Allow synthetic events to pass around stacktraces

Allow a stacktrace from one event to be displayed by the end event of a
synthetic event. This is very useful when looking for the longest l

tracing: Allow synthetic events to pass around stacktraces

Allow a stacktrace from one event to be displayed by the end event of a
synthetic event. This is very useful when looking for the longest latency
of a sleep or something blocked on I/O.

# cd /sys/kernel/tracing/
# echo 's:block_lat pid_t pid; u64 delta; unsigned long[] stack;' > dynamic_events
# echo 'hist:keys=next_pid:ts=common_timestamp.usecs,st=stacktrace if prev_state == 1||prev_state == 2' > events/sched/sched_switch/trigger
# echo 'hist:keys=prev_pid:delta=common_timestamp.usecs-$ts,s=$st:onmax($delta).trace(block_lat,prev_pid,$delta,$s)' >> events/sched/sched_switch/trigger

The above creates a "block_lat" synthetic event that take the stacktrace of
when a task schedules out in either the interruptible or uninterruptible
states, and on a new per process max $delta (the time it was scheduled
out), will print the process id and the stacktrace.

# echo 1 > events/synthetic/block_lat/enable
# cat trace
# TASK-PID CPU# ||||| TIMESTAMP FUNCTION
# | | | ||||| | |
kworker/u16:0-767 [006] d..4. 560.645045: block_lat: pid=767 delta=66 stack=STACK:
=> __schedule
=> schedule
=> pipe_read
=> vfs_read
=> ksys_read
=> do_syscall_64
=> 0x966000aa

<idle>-0 [003] d..4. 561.132117: block_lat: pid=0 delta=413787 stack=STACK:
=> __schedule
=> schedule
=> schedule_hrtimeout_range_clock
=> do_sys_poll
=> __x64_sys_poll
=> do_syscall_64
=> 0x966000aa

<...>-153 [006] d..4. 562.068407: block_lat: pid=153 delta=54 stack=STACK:
=> __schedule
=> schedule
=> io_schedule
=> rq_qos_wait
=> wbt_wait
=> __rq_qos_throttle
=> blk_mq_submit_bio
=> submit_bio_noacct_nocheck
=> ext4_bio_write_page
=> mpage_submit_page
=> mpage_process_page_bufs
=> mpage_prepare_extent_to_map
=> ext4_do_writepages
=> ext4_writepages
=> do_writepages
=> __writeback_single_inode

Link: https://lkml.kernel.org/r/20230117152236.010941267@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Ross Zwisler <zwisler@google.com>
Cc: Ching-lin Yu <chinglinyu@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

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tracing: Make sure trace_printk() can output as soon as it can be used

Currently trace_printk() can be used as soon as early_trace_init() is
called from start_kernel(). But if a crash happens, and
"

tracing: Make sure trace_printk() can output as soon as it can be used

Currently trace_printk() can be used as soon as early_trace_init() is
called from start_kernel(). But if a crash happens, and
"ftrace_dump_on_oops" is set on the kernel command line, all you get will
be:

[ 0.456075] <idle>-0 0dN.2. 347519us : Unknown type 6
[ 0.456075] <idle>-0 0dN.2. 353141us : Unknown type 6
[ 0.456075] <idle>-0 0dN.2. 358684us : Unknown type 6

This is because the trace_printk() event (type 6) hasn't been registered
yet. That gets done via an early_initcall(), which may be early, but not
early enough.

Instead of registering the trace_printk() event (and other ftrace events,
which are not trace events) via an early_initcall(), have them registered at
the same time that trace_printk() can be used. This way, if there is a
crash before early_initcall(), then the trace_printk()s will actually be
useful.

Link: https://lkml.kernel.org/r/20230104161412.019f6c55@gandalf.local.home

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: e725c731e3bb1 ("tracing: Split tracing initialization into two for early initialization")
Reported-by: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Tested-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

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Merge drm/drm-next into drm-misc-next

Backmerging into drm-misc-next to get DRM accelerator infrastructure,
which is required by ipuv driver.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge wireless into wireless-next

Due to the two cherry picked commits from wireless to wireless-next we have
several conflicts in mt76. To avoid any bugs with conflicts merge wireless into
wireless

Merge wireless into wireless-next

Due to the two cherry picked commits from wireless to wireless-next we have
several conflicts in mt76. To avoid any bugs with conflicts merge wireless into
wireless-next.

96f134dc1964 wifi: mt76: handle possible mt76_rx_token_consume failures
fe13dad8992b wifi: mt76: dma: do not increment queue head if mt76_dma_add_buf fails

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Merge tag 'v6.2-rc3' into next

Merge with mainline to bring in timer_shutdown_sync() API.

Merge drm/drm-fixes into drm-misc-fixes

Let's start the fixes cycle.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>

Merge drm/drm-next into drm-intel-next

Sync up with v6.2-rc1.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Merge drm/drm-next into drm-intel-gt-next

Sync after v6.2-rc1 landed in drm-next.

We need to get some dependencies in place before we can merge
the fixes series from Gwan-gyeong and Chris.

Referen

Merge drm/drm-next into drm-intel-gt-next

Sync after v6.2-rc1 landed in drm-next.

We need to get some dependencies in place before we can merge
the fixes series from Gwan-gyeong and Chris.

References: https://lore.kernel.org/all/Y6x5JCDnh2rvh4lA@intel.com/
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

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Merge tag 'v6.2-rc1' into media_tree

Linux 6.2-rc1

* tag 'v6.2-rc1': (14398 commits)
Linux 6.2-rc1
treewide: Convert del_timer*() to timer_shutdown*()
pstore: Properly assign mem_type propert

Merge tag 'v6.2-rc1' into media_tree

Linux 6.2-rc1

* tag 'v6.2-rc1': (14398 commits)
Linux 6.2-rc1
treewide: Convert del_timer*() to timer_shutdown*()
pstore: Properly assign mem_type property
pstore: Make sure CONFIG_PSTORE_PMSG selects CONFIG_RT_MUTEXES
cfi: Fix CFI failure with KASAN
perf python: Fix splitting CC into compiler and options
afs: Stop implementing ->writepage()
afs: remove afs_cache_netfs and afs_zap_permits() declarations
afs: remove variable nr_servers
afs: Fix lost servers_outstanding count
ALSA: usb-audio: Add new quirk FIXED_RATE for JBL Quantum810 Wireless
ALSA: azt3328: Remove the unused function snd_azf3328_codec_outl()
gcov: add support for checksum field
test_maple_tree: add test for mas_spanning_rebalance() on insufficient data
maple_tree: fix mas_spanning_rebalance() on insufficient data
hugetlb: really allocate vma lock for all sharable vmas
kmsan: export kmsan_handle_urb
kmsan: include linux/vmalloc.h
mm/mempolicy: fix memory leak in set_mempolicy_home_node system call
mm, mremap: fix mremap() expanding vma with addr inside vma
...

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Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

No conflicts.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Merge branch 'master' into mm-nonmm-stable

Merge branch 'master' into mm-stable

Merge remote-tracking branch 'torvalds/master' into perf/core

To resolve a trivial merge conflict with c302378bc157f6a7 ("libbpf:
Hashmap interface update to allow both long and void* keys/values"),

Merge remote-tracking branch 'torvalds/master' into perf/core

To resolve a trivial merge conflict with c302378bc157f6a7 ("libbpf:
Hashmap interface update to allow both long and void* keys/values"),
where a function present upstream was removed in the perf tools
development tree.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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