Move all the tracing selftest configs to the bottom of the tracing menu.
There's no reason for them to be interspersed throughout.
Also, move the bootconfig menu to the top.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Move the config that enables the mmiotracer with the other tracers such that
all the tracers are together.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The MMIO test module was by itself, move it to the other test modules. Also,
add the text "Test module" to PREEMPTIRQ_DELAY_TEST as that create a test
module as well.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The features that depend on the function tracer were spread out through the
tracing menu, pull them together as it is easier to manage.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Add a test module that checks the basic functionality of the in-kernel
kprobe event command generation API by creating kprobe events from a
module.
Link: http://lkml.kernel.org/r/97e502b204f9dba948e3fa3a4315448298218787.1580323897.git.zanussi@kernel.org
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Add a test module that checks the basic functionality of the in-kernel
synthetic event generation API by generating and tracing synthetic
events from a module.
Link: http://lkml.kernel.org/r/fcb4dd9eb9eefb70ab20538d3529d51642389664.1580323897.git.zanussi@kernel.org
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Setup tracing options via extra boot config in addition to kernel
command line.
This adds following commands support. These are applied to
the global trace instance.
- ftrace.options = OPT1[,OPT2...]
Enable given ftrace options.
- ftrace.trace_clock = CLOCK
Set given CLOCK to ftrace's trace_clock.
- ftrace.buffer_size = SIZE
Configure ftrace buffer size to SIZE. You can use "KB" or "MB"
for that SIZE.
- ftrace.events = EVENT[, EVENT2...]
Enable given events on boot. You can use a wild card in EVENT.
- ftrace.tracer = TRACER
Set TRACER to current tracer on boot. (e.g. function)
Note that this is NOT replacing the kernel parameters, because
this boot config based setting is later than that. If you want to
trace earlier boot events, you still need kernel parameters.
Link: http://lkml.kernel.org/r/157867237723.17873.17494943526320587488.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Fixes:
- Missing __print_hex_dump undef for processing new function in trace events
- Stop WARN_ON messages when lockdown disables tracing on boot up
Enhancement:
- Debug option to inject trace events from userspace (for rasdaemon)
The enhancement has its own config option and is non invasive. It's been
discussed for sever months and should have been added to my original
push, but I never pulled it into my queue.
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Merge tag 'trace-v5.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull more tracing updates from Steven Rostedt:
"Two fixes and one patch that was missed:
Fixes:
- Missing __print_hex_dump undef for processing new function in trace
events
- Stop WARN_ON messages when lockdown disables tracing on boot up
Enhancement:
- Debug option to inject trace events from userspace (for rasdaemon)"
The enhancement has its own config option and is non invasive. It's been
discussed for sever months and should have been added to my original
push, but I never pulled it into my queue.
* tag 'trace-v5.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Do not create directories if lockdown is in affect
tracing: Introduce trace event injection
tracing: Fix __print_hex_dump scope
We have been trying to use rasdaemon to monitor hardware errors like
correctable memory errors. rasdaemon uses trace events to monitor
various hardware errors. In order to test it, we have to inject some
hardware errors, unfortunately not all of them provide error
injections. MCE does provide a way to inject MCE errors, but errors
like PCI error and devlink error don't, it is not easy to add error
injection to each of them. Instead, it is relatively easier to just
allow users to inject trace events in a generic way so that all trace
events can be injected.
This patch introduces trace event injection, where a new 'inject' is
added to each tracepoint directory. Users could write into this file
with key=value pairs to specify the value of each fields of the trace
event, all unspecified fields are set to zero values by default.
For example, for the net/net_dev_queue tracepoint, we can inject:
INJECT=/sys/kernel/debug/tracing/events/net/net_dev_queue/inject
echo "" > $INJECT
echo "name='test'" > $INJECT
echo "name='test' len=1024" > $INJECT
cat /sys/kernel/debug/tracing/trace
...
<...>-614 [000] .... 36.571483: net_dev_queue: dev= skbaddr=00000000fbf338c2 len=0
<...>-614 [001] .... 136.588252: net_dev_queue: dev=test skbaddr=00000000fbf338c2 len=0
<...>-614 [001] .N.. 208.431878: net_dev_queue: dev=test skbaddr=00000000fbf338c2 len=1024
Triggers could be triggered as usual too:
echo "stacktrace if len == 1025" > /sys/kernel/debug/tracing/events/net/net_dev_queue/trigger
echo "len=1025" > $INJECT
cat /sys/kernel/debug/tracing/trace
...
bash-614 [000] .... 36.571483: net_dev_queue: dev= skbaddr=00000000fbf338c2 len=0
bash-614 [001] .... 136.588252: net_dev_queue: dev=test skbaddr=00000000fbf338c2 len=0
bash-614 [001] .N.. 208.431878: net_dev_queue: dev=test skbaddr=00000000fbf338c2 len=1024
bash-614 [001] .N.1 284.236349: <stack trace>
=> event_inject_write
=> vfs_write
=> ksys_write
=> do_syscall_64
=> entry_SYSCALL_64_after_hwframe
The only thing that can't be injected is string pointers as they
require constant string pointers, this can't be done at run time.
Link: http://lkml.kernel.org/r/20191130045218.18979-1-xiyou.wangcong@gmail.com
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
- PERAMAENT flag to ftrace_ops when attaching a callback to a function
As /proc/sys/kernel/ftrace_enabled when set to zero will disable all
attached callbacks in ftrace, this has a detrimental impact on live
kernel tracing, as it disables all that it patched. If a ftrace_ops
is registered to ftrace with the PERMANENT flag set, it will prevent
ftrace_enabled from being disabled, and if ftrace_enabled is already
disabled, it will prevent a ftrace_ops with PREMANENT flag set from
being registered.
- New register_ftrace_direct(). As eBPF would like to register its own
trampolines to be called by the ftrace nop locations directly,
without going through the ftrace trampoline, this function has been
added. This allows for eBPF trampolines to live along side of
ftrace, perf, kprobe and live patching. It also utilizes the ftrace
enabled_functions file that keeps track of functions that have been
modified in the kernel, to allow for security auditing.
- Allow for kernel internal use of ftrace instances. Subsystems in
the kernel can now create and destroy their own tracing instances
which allows them to have their own tracing buffer, and be able
to record events without worrying about other users from writing over
their data.
- New seq_buf_hex_dump() that lets users use the hex_dump() in their
seq_buf usage.
- Notifications now added to tracing_max_latency to allow user space
to know when a new max latency is hit by one of the latency tracers.
- Wider spread use of generic compare operations for use of bsearch and
friends.
- More synthetic event fields may be defined (32 up from 16)
- Use of xarray for architectures with sparse system calls, for the
system call trace events.
This along with small clean ups and fixes.
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Merge tag 'trace-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"New tracing features:
- New PERMANENT flag to ftrace_ops when attaching a callback to a
function.
As /proc/sys/kernel/ftrace_enabled when set to zero will disable
all attached callbacks in ftrace, this has a detrimental impact on
live kernel tracing, as it disables all that it patched. If a
ftrace_ops is registered to ftrace with the PERMANENT flag set, it
will prevent ftrace_enabled from being disabled, and if
ftrace_enabled is already disabled, it will prevent a ftrace_ops
with PREMANENT flag set from being registered.
- New register_ftrace_direct().
As eBPF would like to register its own trampolines to be called by
the ftrace nop locations directly, without going through the ftrace
trampoline, this function has been added. This allows for eBPF
trampolines to live along side of ftrace, perf, kprobe and live
patching. It also utilizes the ftrace enabled_functions file that
keeps track of functions that have been modified in the kernel, to
allow for security auditing.
- Allow for kernel internal use of ftrace instances.
Subsystems in the kernel can now create and destroy their own
tracing instances which allows them to have their own tracing
buffer, and be able to record events without worrying about other
users from writing over their data.
- New seq_buf_hex_dump() that lets users use the hex_dump() in their
seq_buf usage.
- Notifications now added to tracing_max_latency to allow user space
to know when a new max latency is hit by one of the latency
tracers.
- Wider spread use of generic compare operations for use of bsearch
and friends.
- More synthetic event fields may be defined (32 up from 16)
- Use of xarray for architectures with sparse system calls, for the
system call trace events.
This along with small clean ups and fixes"
* tag 'trace-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (51 commits)
tracing: Enable syscall optimization for MIPS
tracing: Use xarray for syscall trace events
tracing: Sample module to demonstrate kernel access to Ftrace instances.
tracing: Adding new functions for kernel access to Ftrace instances
tracing: Fix Kconfig indentation
ring-buffer: Fix typos in function ring_buffer_producer
ftrace: Use BIT() macro
ftrace: Return ENOTSUPP when DYNAMIC_FTRACE_WITH_DIRECT_CALLS is not configured
ftrace: Rename ftrace_graph_stub to ftrace_stub_graph
ftrace: Add a helper function to modify_ftrace_direct() to allow arch optimization
ftrace: Add helper find_direct_entry() to consolidate code
ftrace: Add another check for match in register_ftrace_direct()
ftrace: Fix accounting bug with direct->count in register_ftrace_direct()
ftrace/selftests: Fix spelling mistake "wakeing" -> "waking"
tracing: Increase SYNTH_FIELDS_MAX for synthetic_events
ftrace/samples: Add a sample module that implements modify_ftrace_direct()
ftrace: Add modify_ftrace_direct()
tracing: Add missing "inline" in stub function of latency_fsnotify()
tracing: Remove stray tab in TRACE_EVAL_MAP_FILE's help text
tracing: Use seq_buf_hex_dump() to dump buffers
...
Adjust indentation from spaces to tab (+optional two spaces) as in
coding style with command like:
$ sed -e 's/^ /\t/' -i */Kconfig
Link: http://lkml.kernel.org/r/20191120133807.12741-1-krzk@kernel.org
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
There was a stray tab in the help text of the aforementioned config
option which showed like this:
The "print fmt" of the trace events will show the enum/sizeof names
instead of their values. This can cause problems for user space tools
...
in menuconfig. Remove it and end a sentence with a fullstop.
No functional changes.
Link: http://lkml.kernel.org/r/20191112174219.10933-1-bp@alien8.de
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This burst feature enables the user to generate a burst of
preempt/irqsoff latencies. This makes it possible to test whether we
are able to detect latencies that systematically occur very close to
each other.
The maximum burst size is 10. We also create 10 identical test
functions, so that we get 10 different backtraces; this is useful
when we want to test whether we can detect all the latencies in a
burst. Otherwise, there would be no easy way of differentiating
between which latency in a burst was captured by the tracer.
In addition, there is a sysfs trigger, so that it's not necessary to
reload the module to repeat the test. The trigger will appear as
/sys/kernel/preemptirq_delay_test/trigger in sysfs.
Link: http://lkml.kernel.org/r/20191008220824.7911-3-viktor.rosendahl@gmail.com
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Viktor Rosendahl (BMW) <viktor.rosendahl@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Add the start of the functionality to allow other trampolines to use the
ftrace mcount/fentry/nop location. This adds two new functions:
register_ftrace_direct() and unregister_ftrace_direct()
Both take two parameters: the first is the instruction address of where the
mcount/fentry/nop exists, and the second is the trampoline to have that
location called.
This will handle cases where ftrace is already used on that same location,
and will make it still work, where the registered direct called trampoline
will get called after all the registered ftrace callers are handled.
Currently, it will not allow for IP_MODIFY functions to be called at the
same locations, which include some kprobes and live kernel patching.
At this point, no architecture supports this. This is only the start of
implementing the framework.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pull networking updates from David Miller:
1) Support IPV6 RA Captive Portal Identifier, from Maciej Żenczykowski.
2) Use bio_vec in the networking instead of custom skb_frag_t, from
Matthew Wilcox.
3) Make use of xmit_more in r8169 driver, from Heiner Kallweit.
4) Add devmap_hash to xdp, from Toke Høiland-Jørgensen.
5) Support all variants of 5750X bnxt_en chips, from Michael Chan.
6) More RTNL avoidance work in the core and mlx5 driver, from Vlad
Buslov.
7) Add TCP syn cookies bpf helper, from Petar Penkov.
8) Add 'nettest' to selftests and use it, from David Ahern.
9) Add extack support to drop_monitor, add packet alert mode and
support for HW drops, from Ido Schimmel.
10) Add VLAN offload to stmmac, from Jose Abreu.
11) Lots of devm_platform_ioremap_resource() conversions, from
YueHaibing.
12) Add IONIC driver, from Shannon Nelson.
13) Several kTLS cleanups, from Jakub Kicinski.
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1930 commits)
mlxsw: spectrum_buffers: Add the ability to query the CPU port's shared buffer
mlxsw: spectrum: Register CPU port with devlink
mlxsw: spectrum_buffers: Prevent changing CPU port's configuration
net: ena: fix incorrect update of intr_delay_resolution
net: ena: fix retrieval of nonadaptive interrupt moderation intervals
net: ena: fix update of interrupt moderation register
net: ena: remove all old adaptive rx interrupt moderation code from ena_com
net: ena: remove ena_restore_ethtool_params() and relevant fields
net: ena: remove old adaptive interrupt moderation code from ena_netdev
net: ena: remove code duplication in ena_com_update_nonadaptive_moderation_interval _*()
net: ena: enable the interrupt_moderation in driver_supported_features
net: ena: reimplement set/get_coalesce()
net: ena: switch to dim algorithm for rx adaptive interrupt moderation
net: ena: add intr_moder_rx_interval to struct ena_com_dev and use it
net: phy: adin: implement Energy Detect Powerdown mode via phy-tunable
ethtool: implement Energy Detect Powerdown support via phy-tunable
xen-netfront: do not assume sk_buff_head list is empty in error handling
s390/ctcm: Delete unnecessary checks before the macro call “dev_kfree_skb”
net: ena: don't wake up tx queue when down
drop_monitor: Better sanitize notified packets
...
PERF_EVENT_IOC_SET_BPF supports uprobes since v4.3, and tracepoints
since v4.7 via commit 04a22fae4c ("tracing, perf: Implement BPF
programs attached to uprobes"), and commit 98b5c2c65c ("perf, bpf:
allow bpf programs attach to tracepoints") respectively.
Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by
CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same
functionality which today depends on CONFIG_PREEMPT.
Switch the conditionals in the tracer over to CONFIG_PREEMPTION.
This is the first step to make the tracer work on RT. The other small
tweaks are submitted separately.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20190726212124.409766323@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by
CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same
functionality which today depends on CONFIG_PREEMPT.
Switch the conditionals in RCU to use CONFIG_PREEMPTION.
That's the first step towards RCU on RT. The further tweaks are work in
progress. This neither touches the selftest bits which need a closer look
by Paul.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20190726212124.210156346@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
- Add user space specific memory reading for kprobes
- Allow kprobes to be executed earlier in boot
The rest are mostly just various clean ups and small fixes.
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Merge tag 'trace-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"The main changes in this release include:
- Add user space specific memory reading for kprobes
- Allow kprobes to be executed earlier in boot
The rest are mostly just various clean ups and small fixes"
* tag 'trace-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits)
tracing: Make trace_get_fields() global
tracing: Let filter_assign_type() detect FILTER_PTR_STRING
tracing: Pass type into tracing_generic_entry_update()
ftrace/selftest: Test if set_event/ftrace_pid exists before writing
ftrace/selftests: Return the skip code when tracing directory not configured in kernel
tracing/kprobe: Check registered state using kprobe
tracing/probe: Add trace_event_call accesses APIs
tracing/probe: Add probe event name and group name accesses APIs
tracing/probe: Add trace flag access APIs for trace_probe
tracing/probe: Add trace_event_file access APIs for trace_probe
tracing/probe: Add trace_event_call register API for trace_probe
tracing/probe: Add trace_probe init and free functions
tracing/uprobe: Set print format when parsing command
tracing/kprobe: Set print format right after parsed command
kprobes: Fix to init kprobes in subsys_initcall
tracepoint: Use struct_size() in kmalloc()
ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS
ftrace: Enable trampoline when rec count returns back to one
tracing/kprobe: Do not run kprobe boot tests if kprobe_event is on cmdline
tracing: Make a separate config for trace event self tests
...
The trace event self tests enable loop through *all* events, enables each
one, one at a time, runs some code to trigger various events (not
necessarily the same events), and checks if anything went wrong. The issue
is that trace events are usually the least likely start up test to cause a
problem, but they take the longest to run (because there are so many
events). When one of the other tests trigger a bug, the trace event start up
tests causes the bisect to take much longer, because it takes 10s of seconds
to get through the trace event tests.
By making them a separate config (even though they are enabled by default if
start up tests are set), it is possible to turn them off and still run the
other tracing start up tests much quicker.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
gpio tracing was made configurable in 4.4-rc1 (commit ddd70280bf
("tracing: gpio: Add Kconfig option for enabling/disabling trace
events")). Since then it is the only event type that can be compiled
conditionally. Given that there is only little overhead I don't
understand the reasoning and I was annoyed more than once that gpio
events were not available without recompiling.
So drop the Kconfig symbol and make gpio events available
unconditionally.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Since -Wmaybe-uninitialized was introduced by GCC 4.7, we have patched
various false positives:
- commit e74fc973b6 ("Turn off -Wmaybe-uninitialized when building
with -Os") turned off this option for -Os.
- commit 815eb71e71 ("Kbuild: disable 'maybe-uninitialized' warning
for CONFIG_PROFILE_ALL_BRANCHES") turned off this option for
CONFIG_PROFILE_ALL_BRANCHES
- commit a76bcf557e ("Kbuild: enable -Wmaybe-uninitialized warning
for "make W=1"") turned off this option for GCC < 4.9
Arnd provided more explanation in https://lkml.org/lkml/2017/3/14/903
I think this looks better by shifting the logic from Makefile to Kconfig.
Link: https://github.com/ClangBuiltLinux/linux/issues/350
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Use dyn_event framework for synthetic events. This shows
synthetic events on "tracing/dynamic_events" file in addition
to tracing/synthetic_events interface.
User can also define new events via tracing/dynamic_events
with "s:" prefix. So, the new syntax is below;
s:[synthetic/]EVENT_NAME TYPE ARG; [TYPE ARG;]...
To remove events via tracing/dynamic_events, you can use
"-:" prefix as same as other events.
Link: http://lkml.kernel.org/r/154140861301.17322.15454611233735614508.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Use dyn_event framework for uprobe events. This shows
uprobe events on "dynamic_events" file.
User can also define new uprobe events via dynamic_events.
Link: http://lkml.kernel.org/r/154140858481.17322.9091293846515154065.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Use dyn_event framework for kprobe events. This shows
kprobe events on "tracing/dynamic_events" file.
User can also define new events via tracing/dynamic_events.
Link: http://lkml.kernel.org/r/154140855646.17322.6619219995865980392.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Add unified dynamic event framework for ftrace kprobes, uprobes
and synthetic events. Those dynamic events can be co-exist on
same file because those syntax doesn't overlap.
This introduces a framework part which provides a unified tracefs
interface and operations.
Link: http://lkml.kernel.org/r/154140852824.17322.12250362185969352095.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
from being traced by kprobes. During my testing, I found that there's places
that we may want to add kprobes to notrace, thus we may end up changing this
code before 4.19 is released. The history behind this change is that we
found that adding kprobes to various notrace functions caused the kernel to
crashed. We took the safe route and decided not to allow kprobes to trace
any notrace function. But because notrace is added to functions that just
cause weird side effects to the function tracer, but are still safe,
preventing kprobes for all notrace functios may be too much of a big hammer.
One such place is __schedule() is marked notrace, to keep function tracer
from doing strange recursive loops when it gets traced with NEED_RESCHED
set. With this change, one can not add kprobes to the scheduler.
Masami also added code to use gcov on ftrace.
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Merge tag 'trace-v4.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"Masami found an off by one bug in the code that keeps "notrace"
functions from being traced by kprobes. During my testing, I found
that there's places that we may want to add kprobes to notrace, thus
we may end up changing this code before 4.19 is released.
The history behind this change is that we found that adding kprobes to
various notrace functions caused the kernel to crashed. We took the
safe route and decided not to allow kprobes to trace any notrace
function.
But because notrace is added to functions that just cause weird side
effects to the function tracer, but are still safe, preventing kprobes
for all notrace functios may be too much of a big hammer.
One such place is __schedule() is marked notrace, to keep function
tracer from doing strange recursive loops when it gets traced with
NEED_RESCHED set. With this change, one can not add kprobes to the
scheduler.
Masami also added code to use gcov on ftrace"
* tag 'trace-v4.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing/kprobes: Fix to check notrace function with correct range
tracing: Allow gcov profiling on only ftrace subsystem
Add GCOV_PROFILE_FTRACE to allow gcov profiling on only files in ftrace
subsystem. This config option will be used for checking kselftest/ftrace
coverage.
Link: http://lkml.kernel.org/r/153483647755.32472.4746349899604275441.stgit@devbox
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
- Restructure of lockdep and latency tracers
This is the biggest change. Joel Fernandes restructured the hooks
from irqs and preemption disabling and enabling. He got rid of
a lot of the preprocessor #ifdef mess that they caused.
He turned both lockdep and the latency tracers to use trace events
inserted in the preempt/irqs disabling paths. But unfortunately,
these started to cause issues in corner cases. Thus, parts of the
code was reverted back to where lockde and the latency tracers
just get called directly (without using the trace events).
But because the original change cleaned up the code very nicely
we kept that, as well as the trace events for preempt and irqs
disabling, but they are limited to not being called in NMIs.
- Have trace events use SRCU for "rcu idle" calls. This was required
for the preempt/irqs off trace events. But it also had to not
allow them to be called in NMI context. Waiting till Paul makes
an NMI safe SRCU API.
- New notrace SRCU API to allow trace events to use SRCU.
- Addition of mcount-nop option support
- SPDX headers replacing GPL templates.
- Various other fixes and clean ups.
- Some fixes are marked for stable, but were not fully tested
before the merge window opened.
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Merge tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
- Restructure of lockdep and latency tracers
This is the biggest change. Joel Fernandes restructured the hooks
from irqs and preemption disabling and enabling. He got rid of a lot
of the preprocessor #ifdef mess that they caused.
He turned both lockdep and the latency tracers to use trace events
inserted in the preempt/irqs disabling paths. But unfortunately,
these started to cause issues in corner cases. Thus, parts of the
code was reverted back to where lockdep and the latency tracers just
get called directly (without using the trace events). But because the
original change cleaned up the code very nicely we kept that, as well
as the trace events for preempt and irqs disabling, but they are
limited to not being called in NMIs.
- Have trace events use SRCU for "rcu idle" calls. This was required
for the preempt/irqs off trace events. But it also had to not allow
them to be called in NMI context. Waiting till Paul makes an NMI safe
SRCU API.
- New notrace SRCU API to allow trace events to use SRCU.
- Addition of mcount-nop option support
- SPDX headers replacing GPL templates.
- Various other fixes and clean ups.
- Some fixes are marked for stable, but were not fully tested before
the merge window opened.
* tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits)
tracing: Fix SPDX format headers to use C++ style comments
tracing: Add SPDX License format tags to tracing files
tracing: Add SPDX License format to bpf_trace.c
blktrace: Add SPDX License format header
s390/ftrace: Add -mfentry and -mnop-mcount support
tracing: Add -mcount-nop option support
tracing: Avoid calling cc-option -mrecord-mcount for every Makefile
tracing: Handle CC_FLAGS_FTRACE more accurately
Uprobe: Additional argument arch_uprobe to uprobe_write_opcode()
Uprobes: Simplify uprobe_register() body
tracepoints: Free early tracepoints after RCU is initialized
uprobes: Use synchronize_rcu() not synchronize_sched()
tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister()
ftrace: Remove unused pointer ftrace_swapper_pid
tracing: More reverting of "tracing: Centralize preemptirq tracepoints and unify their usage"
tracing/irqsoff: Handle preempt_count for different configs
tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage"
tracing: irqsoff: Account for additional preempt_disable
trace: Use rcu_dereference_raw for hooks from trace-event subsystem
tracing/kprobes: Fix within_notrace_func() to check only notrace functions
...
-mcount-nop gcc option generates the calls to the profiling functions
as nops which allows to avoid patching mcount jump with NOP instructions
initially.
-mcount-nop gcc option will be activated if platform selects
HAVE_NOP_MCOUNT and gcc actually supports it.
In addition to that CC_USING_NOP_MCOUNT is defined and could be used by
architectures to adapt ftrace patching behavior.
Link: http://lkml.kernel.org/r/patch-3.thread-aa7b8d.git-e02ed2dc082b.your-ad-here.call-01533557518-ext-9465@work.hours
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This patch detaches the preemptirq tracepoints from the tracers and
keeps it separate.
Advantages:
* Lockdep and irqsoff event can now run in parallel since they no longer
have their own calls.
* This unifies the usecase of adding hooks to an irqsoff and irqson
event, and a preemptoff and preempton event.
3 users of the events exist:
- Lockdep
- irqsoff and preemptoff tracers
- irqs and preempt trace events
The unification cleans up several ifdefs and makes the code in preempt
tracer and irqsoff tracers simpler. It gets rid of all the horrific
ifdeferry around PROVE_LOCKING and makes configuration of the different
users of the tracepoints more easy and understandable. It also gets rid
of the time_* function calls from the lockdep hooks used to call into
the preemptirq tracer which is not needed anymore. The negative delta in
lines of code in this patch is quite large too.
In the patch we introduce a new CONFIG option PREEMPTIRQ_TRACEPOINTS
as a single point for registering probes onto the tracepoints. With
this,
the web of config options for preempt/irq toggle tracepoints and its
users becomes:
PREEMPT_TRACER PREEMPTIRQ_EVENTS IRQSOFF_TRACER PROVE_LOCKING
| | \ | |
\ (selects) / \ \ (selects) /
TRACE_PREEMPT_TOGGLE ----> TRACE_IRQFLAGS
\ /
\ (depends on) /
PREEMPTIRQ_TRACEPOINTS
Other than the performance tests mentioned in the previous patch, I also
ran the locking API test suite. I verified that all tests cases are
passing.
I also injected issues by not registering lockdep probes onto the
tracepoints and I see failures to confirm that the probes are indeed
working.
This series + lockdep probes not registered (just to inject errors):
[ 0.000000] hard-irqs-on + irq-safe-A/21: ok | ok | ok |
[ 0.000000] soft-irqs-on + irq-safe-A/21: ok | ok | ok |
[ 0.000000] sirq-safe-A => hirqs-on/12:FAILED|FAILED| ok |
[ 0.000000] sirq-safe-A => hirqs-on/21:FAILED|FAILED| ok |
[ 0.000000] hard-safe-A + irqs-on/12:FAILED|FAILED| ok |
[ 0.000000] soft-safe-A + irqs-on/12:FAILED|FAILED| ok |
[ 0.000000] hard-safe-A + irqs-on/21:FAILED|FAILED| ok |
[ 0.000000] soft-safe-A + irqs-on/21:FAILED|FAILED| ok |
[ 0.000000] hard-safe-A + unsafe-B #1/123: ok | ok | ok |
[ 0.000000] soft-safe-A + unsafe-B #1/123: ok | ok | ok |
With this series + lockdep probes registered, all locking tests pass:
[ 0.000000] hard-irqs-on + irq-safe-A/21: ok | ok | ok |
[ 0.000000] soft-irqs-on + irq-safe-A/21: ok | ok | ok |
[ 0.000000] sirq-safe-A => hirqs-on/12: ok | ok | ok |
[ 0.000000] sirq-safe-A => hirqs-on/21: ok | ok | ok |
[ 0.000000] hard-safe-A + irqs-on/12: ok | ok | ok |
[ 0.000000] soft-safe-A + irqs-on/12: ok | ok | ok |
[ 0.000000] hard-safe-A + irqs-on/21: ok | ok | ok |
[ 0.000000] soft-safe-A + irqs-on/21: ok | ok | ok |
[ 0.000000] hard-safe-A + unsafe-B #1/123: ok | ok | ok |
[ 0.000000] soft-safe-A + unsafe-B #1/123: ok | ok | ok |
Link: http://lkml.kernel.org/r/20180730222423.196630-4-joel@joelfernandes.org
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Prohibit kprobe-events probing on notrace functions. Since probing on a
notrace function can cause a recursive event call. In most cases those are just
skipped, but in some cases it falls into an infinite recursive call.
This protection can be disabled by the kconfig
CONFIG_KPROBE_EVENTS_ON_NOTRACE=y, but it is highly recommended to keep it
"n" for normal kernel builds. Note that this is only available if "kprobes on
ftrace" has been implemented on the target arch and CONFIG_KPROBES_ON_FTRACE=y.
Link: http://lkml.kernel.org/r/153294601436.32740.10557881188933661239.stgit@devbox
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Francis Deslauriers <francis.deslauriers@efficios.com>
[ Slight grammar and spelling fixes ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The name of the directory for per-cpu function statistics
is trace_stat, not trace_stats.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Here we introduce a test module for introducing a long preempt or irq
disable delay in the kernel which the preemptoff or irqsoff tracers can
detect. This module is to be used only for test purposes and is default
disabled.
Following is the expected output (only briefly shown) that can be parsed
to verify that the tracers are working correctly. We will use this from
the kselftests in future patches.
For the preemptoff tracer:
echo preemptoff > /d/tracing/current_tracer
sleep 1
insmod ./preemptirq_delay_test.ko test_mode=preempt delay=500000
sleep 1
bash-4.3# cat /d/tracing/trace
preempt -1066 2...2 0us@: preemptirq_delay_run <-preemptirq_delay_run
preempt -1066 2...2 500002us : preemptirq_delay_run <-preemptirq_delay_run
preempt -1066 2...2 500004us : tracer_preempt_on <-preemptirq_delay_run
preempt -1066 2...2 500012us : <stack trace>
=> kthread
=> ret_from_fork
For the irqsoff tracer:
echo irqsoff > /d/tracing/current_tracer
sleep 1
insmod ./preemptirq_delay_test.ko test_mode=irq delay=500000
sleep 1
bash-4.3# cat /d/tracing/trace
irq dis -1069 1d..1 0us@: preemptirq_delay_run
irq dis -1069 1d..1 500001us : preemptirq_delay_run
irq dis -1069 1d..1 500002us : tracer_hardirqs_on <-preemptirq_delay_run
irq dis -1069 1d..1 500005us : <stack trace>
=> ret_from_fork
Link: http://lkml.kernel.org/r/20180712213611.GA8743@joelaf.mtv.corp.google.com
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Julia Cartwright <julia@ni.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Glexiner <tglx@linutronix.de>
Cc: Todd Kjos <tkjos@google.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[ Erick is a co-developer of this commit ]
Signed-off-by: Erick Reyes <erickreyes@google.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Despite being mentioned at Documentation/trace/ftrace.rst as a
rst file, this file was still a text one, with several issues.
Convert it to ReST and add it to the trace index:
- Mark the document title as such;
- Identify and indent the literal blocks;
- Use the proper markups for table.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
As we move stuff around, some doc references are broken. Fix some of
them via this script:
./scripts/documentation-file-ref-check --fix
Manually checked if the produced result is valid, removing a few
false-positives.
Acked-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
config TRACING_SUPPORT has an exception for PPC32, because PPC32
didn't have irqflags tracing support.
But that hasn't been true since commit 5d38902c48 ("powerpc: Add
irqtrace support for 32-bit powerpc") (Jun 2009).
So remove the exception for PPC32 and the comment.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
I regularly get 50 MB - 60 MB files during kernel randconfig builds.
These large files mostly contain (many repeats of; e.g., 124,594):
In file included from ../include/linux/string.h:6:0,
from ../include/linux/uuid.h:20,
from ../include/linux/mod_devicetable.h:13,
from ../scripts/mod/devicetable-offsets.c:3:
../include/linux/compiler.h:64:4: warning: '______f' is static but declared in inline function 'strcpy' which is not static [enabled by default]
______f = { \
^
../include/linux/compiler.h:56:23: note: in expansion of macro '__trace_if'
^
../include/linux/string.h:425:2: note: in expansion of macro 'if'
if (p_size == (size_t)-1 && q_size == (size_t)-1)
^
This only happens when CONFIG_FORTIFY_SOURCE=y and
CONFIG_PROFILE_ALL_BRANCHES=y, so prevent PROFILE_ALL_BRANCHES if
FORTIFY_SOURCE=y.
Link: http://lkml.kernel.org/r/9199446b-a141-c0c3-9678-a3f9107f2750@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Since error-injection framework is not limited to be used
by kprobes, nor bpf. Other kernel subsystems can use it
freely for checking safeness of error-injection, e.g.
livepatch, ftrace etc.
So this separate error-injection framework from kprobes.
Some differences has been made:
- "kprobe" word is removed from any APIs/structures.
- BPF_ALLOW_ERROR_INJECTION() is renamed to
ALLOW_ERROR_INJECTION() since it is not limited for BPF too.
- CONFIG_FUNCTION_ERROR_INJECTION is the config item of this
feature. It is automatically enabled if the arch supports
error injection feature for kprobe or ftrace etc.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Check whether error injectable event is on function entry or not.
Currently it checks the event is ftrace-based kprobes or not,
but that is wrong. It should check if the event is on the entry
of target function. Since error injection will override a function
to just return with modified return value, that operation must
be done before the target function starts making stackframe.
As a side effect, bpf error injection is no need to depend on
function-tracer. It can work with sw-breakpoint based kprobe
events too.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Daniel Borkmann says:
====================
pull-request: bpf-next 2017-12-18
The following pull-request contains BPF updates for your *net-next* tree.
The main changes are:
1) Allow arbitrary function calls from one BPF function to another BPF function.
As of today when writing BPF programs, __always_inline had to be used in
the BPF C programs for all functions, unnecessarily causing LLVM to inflate
code size. Handle this more naturally with support for BPF to BPF calls
such that this __always_inline restriction can be overcome. As a result,
it allows for better optimized code and finally enables to introduce core
BPF libraries in the future that can be reused out of different projects.
x86 and arm64 JIT support was added as well, from Alexei.
2) Add infrastructure for tagging functions as error injectable and allow for
BPF to return arbitrary error values when BPF is attached via kprobes on
those. This way of injecting errors generically eases testing and debugging
without having to recompile or restart the kernel. Tags for opting-in for
this facility are added with BPF_ALLOW_ERROR_INJECTION(), from Josef.
3) For BPF offload via nfp JIT, add support for bpf_xdp_adjust_head() helper
call for XDP programs. First part of this work adds handling of BPF
capabilities included in the firmware, and the later patches add support
to the nfp verifier part and JIT as well as some small optimizations,
from Jakub.
4) The bpftool now also gets support for basic cgroup BPF operations such
as attaching, detaching and listing current BPF programs. As a requirement
for the attach part, bpftool can now also load object files through
'bpftool prog load'. This reuses libbpf which we have in the kernel tree
as well. bpftool-cgroup man page is added along with it, from Roman.
5) Back then commit e87c6bc385 ("bpf: permit multiple bpf attachments for
a single perf event") added support for attaching multiple BPF programs
to a single perf event. Given they are configured through perf's ioctl()
interface, the interface has been extended with a PERF_EVENT_IOC_QUERY_BPF
command in this work in order to return an array of one or multiple BPF
prog ids that are currently attached, from Yonghong.
6) Various minor fixes and cleanups to the bpftool's Makefile as well
as a new 'uninstall' and 'doc-uninstall' target for removing bpftool
itself or prior installed documentation related to it, from Quentin.
7) Add CONFIG_CGROUP_BPF=y to the BPF kernel selftest config file which is
required for the test_dev_cgroup test case to run, from Naresh.
8) Fix reporting of XDP prog_flags for nfp driver, from Jakub.
9) Fix libbpf's exit code from the Makefile when libelf was not found in
the system, also from Jakub.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Error injection is sloppy and very ad-hoc. BPF could fill this niche
perfectly with it's kprobe functionality. We could make sure errors are
only triggered in specific call chains that we care about with very
specific situations. Accomplish this with the bpf_override_funciton
helper. This will modify the probe'd callers return value to the
specified value and set the PC to an override function that simply
returns, bypassing the originally probed function. This gives us a nice
clean way to implement systematic error injection for all of our code
paths.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When CONFIG_TRACING is disabled, the new preemptirq events tracer
produces a build failure:
In file included from kernel/trace/trace_irqsoff.c:17:0:
kernel/trace/trace.h: In function 'trace_test_and_set_recursion':
kernel/trace/trace.h:542:28: error: 'struct task_struct' has no member named 'trace_recursion'
Adding an explicit dependency avoids the broken configuration.
Link: http://lkml.kernel.org/r/20171103104031.270375-1-arnd@arndb.de
Fixes: d59158162e ("tracing: Add support for preempt and irq enable/disable events")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
- Now allow module init functions to be traced
- Clean up some unused or not used by config events (saves space)
- Clean up of trace histogram code
- Add support for preempt and interrupt enabled/disable events
- Other various clean ups
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Merge tag 'trace-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from
- allow module init functions to be traced
- clean up some unused or not used by config events (saves space)
- clean up of trace histogram code
- add support for preempt and interrupt enabled/disable events
- other various clean ups
* tag 'trace-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (30 commits)
tracing, thermal: Hide cpu cooling trace events when not in use
tracing, thermal: Hide devfreq trace events when not in use
ftrace: Kill FTRACE_OPS_FL_PER_CPU
perf/ftrace: Small cleanup
perf/ftrace: Fix function trace events
perf/ftrace: Revert ("perf/ftrace: Fix double traces of perf on ftrace:function")
tracing, dma-buf: Remove unused trace event dma_fence_annotate_wait_on
tracing, memcg, vmscan: Hide trace events when not in use
tracing/xen: Hide events that are not used when X86_PAE is not defined
tracing: mark trace_test_buffer as __maybe_unused
printk: Remove superfluous memory barriers from printk_safe
ftrace: Clear hashes of stale ips of init memory
tracing: Add support for preempt and irq enable/disable events
tracing: Prepare to add preempt and irq trace events
ftrace/kallsyms: Have /proc/kallsyms show saved mod init functions
ftrace: Add freeing algorithm to free ftrace_mod_maps
ftrace: Save module init functions kallsyms symbols for tracing
ftrace: Allow module init functions to be traced
ftrace: Add a ftrace_free_mem() function for modules to use
tracing: Reimplement log2
...
Preempt and irq trace events can be used for tracing the start and
end of an atomic section which can be used by a trace viewer like
systrace to graphically view the start and end of an atomic section and
correlate them with latencies and scheduling issues.
This also serves as a prelude to using synthetic events or probes to
rewrite the preempt and irqsoff tracers, along with numerous benefits of
using trace events features for these events.
Link: http://lkml.kernel.org/r/20171006005432.14244-3-joelaf@google.com
Link: http://lkml.kernel.org/r/20171010225137.17370-1-joelaf@google.com
Cc: Peter Zilstra <peterz@infradead.org>
Cc: kernel-team@android.com
Signed-off-by: Joel Fernandes <joelaf@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
