linux-toradex.git/kernel/trace/Makefile, branch v5.10-rc3

Merge tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2020-08-09T21:10:26+00:00

Pull Kbuild updates from Masahiro Yamada:

 - run the checker (e.g. sparse) after the compiler

 - remove unneeded cc-option tests for old compiler flags

 - fix tar-pkg to install dtbs

 - introduce ccflags-remove-y and asflags-remove-y syntax

 - allow to trace functions in sub-directories of lib/

 - introduce hostprogs-always-y and userprogs-always-y syntax

 - various Makefile cleanups

* tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: stop filtering out $(GCC_PLUGINS_CFLAGS) from cc-option base
  kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled
  kbuild: introduce hostprogs-always-y and userprogs-always-y
  kbuild: sort hostprogs before passing it to ifneq
  kbuild: move host .so build rules to scripts/gcc-plugins/Makefile
  kbuild: Replace HTTP links with HTTPS ones
  kbuild: trace functions in subdirectories of lib/
  kbuild: introduce ccflags-remove-y and asflags-remove-y
  kbuild: do not export LDFLAGS_vmlinux
  kbuild: always create directories of targets
  powerpc/boot: add DTB to 'targets'
  kbuild: buildtar: add dtbs support
  kbuild: remove cc-option test of -ffreestanding
  kbuild: remove cc-option test of -fno-stack-protector
  Revert "kbuild: Create directory for target DTB"
  kbuild: run the checker after the compiler

kbuild: introduce ccflags-remove-y and asflags-remove-y

2020-08-09T16:32:59+00:00

CFLAGS_REMOVE_.o filters out flags when compiling a particular
object, but there is no convenient way to do that for every object in
a directory.

Add ccflags-remove-y and asflags-remove-y to make it easily.

Use ccflags-remove-y to clean up some Makefiles.

The add/remove order works as follows:

 [1] KBUILD_CFLAGS specifies compiler flags used globally

 [2] ccflags-y adds compiler flags for all objects in the
     current Makefile

 [3] ccflags-remove-y removes compiler flags for all objects in the
     current Makefile (New feature)

 [4] CFLAGS_ adds compiler flags per file.

 [5] CFLAGS_REMOVE_ removes compiler flags per file.

Having [3] before [4] allows us to remove flags from most (but not all)
objects in the current Makefile.

For example, kernel/trace/Makefile removes $(CC_FLAGS_FTRACE)
from all objects in the directory, then adds it back to
trace_selftest_dynamic.o and CFLAGS_trace_kprobe_selftest.o

The same applies to lib/livepatch/Makefile.

Please note ccflags-remove-y has no effect to the sub-directories.
In contrast, the previous notation got rid of compiler flags also from
all the sub-directories.

The following are not affected because they have no sub-directories:

  arch/arm/boot/compressed/
  arch/powerpc/xmon/
  arch/sh/
  kernel/trace/

However, lib/ has several sub-directories.

To keep the behavior, I added ccflags-remove-y to all Makefiles
in subdirectories of lib/, except the following:

  lib/vdso/Makefile        - Kbuild does not descend into this Makefile
  lib/raid/test/Makefile   - This is not used for the kernel build

I think commit 2464a609ded0 ("ftrace: do not trace library functions")
excluded too much. In the next commit, I will remove ccflags-remove-y
from the sub-directories of lib/.

Suggested-by: Sami Tolvanen 
Signed-off-by: Masahiro Yamada 
Acked-by: Steven Rostedt (VMware) 
Acked-by: Michael Ellerman  (powerpc)
Acked-by: Brendan Higgins  (KUnit)
Tested-by: Anders Roxell

bpf: Use dedicated bpf_trace_printk event instead of trace_printk()

2020-07-13T23:55:49+00:00

The bpf helper bpf_trace_printk() uses trace_printk() under the hood.
This leads to an alarming warning message originating from trace
buffer allocation which occurs the first time a program using
bpf_trace_printk() is loaded.

We can instead create a trace event for bpf_trace_printk() and enable
it in-kernel when/if we encounter a program using the
bpf_trace_printk() helper.  With this approach, trace_printk()
is not used directly and no warning message appears.

This work was started by Steven (see Link) and finished by Alan; added
Steven's Signed-off-by with his permission.

Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Alan Maguire 
Signed-off-by: Alexei Starovoitov 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/r/20200628194334.6238b933@oasis.local.home
Link: https://lore.kernel.org/bpf/1594641154-18897-2-git-send-email-alan.maguire@oracle.com

Rebase locking/kcsan to locking/urgent

2020-06-11T18:02:46+00:00

Merge the state of the locking kcsan branch before the read/write_once()
and the atomics modifications got merged.

Squash the fallout of the rebase on top of the read/write once and atomic
fallback work into the merge. The history of the original branch is
preserved in tag locking-kcsan-2020-06-02.

Signed-off-by: Thomas Gleixner

tracing: Move synthetic events to a separate file

2020-06-01T12:23:22+00:00

With the addition of the in-kernel synthetic event API, synthetic
events are no longer specifically tied to the histogram triggers.

The synthetic event code is also making trace_event_hist.c very
bloated, so for those reasons, move it to a separate file,
trace_events_synth.c, along with a new trace_synth.h header file.

Because synthetic events are now independent from hist triggers, add a
new CONFIG_SYNTH_EVENTS config option, and have CONFIG_HIST_TRIGGERS
select it, and have CONFIG_SYNTH_EVENT_GEN_TEST depend on it.

Link: http://lkml.kernel.org/r/4d1fa1f85ed5982706ac44844ac92451dcb04715.1590693308.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi 
Signed-off-by: Steven Rostedt (VMware)

kcsan, trace: Make KCSAN compatible with tracing

2020-03-21T08:44:41+00:00

Previously the system would lock up if ftrace was enabled together with
KCSAN. This is due to recursion on reporting if the tracer code is
instrumented with KCSAN.

To avoid this for all types of tracing, disable KCSAN instrumentation
for all of kernel/trace.

Furthermore, since KCSAN relies on udelay() to introduce delay, we have
to disable ftrace for udelay() (currently done for x86) in case KCSAN is
used together with lockdep and ftrace. The reason is that it may corrupt
lockdep IRQ flags tracing state due to a peculiar case of recursion
(details in Makefile comment).

Reported-by: Qian Cai 
Tested-by: Qian Cai 
Acked-by: Steven Rostedt (VMware) 
Signed-off-by: Marco Elver 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Ingo Molnar

tracing: Add kprobe event command generation test module

2020-01-30T14:46:28+00:00

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 
Signed-off-by: Tom Zanussi 
Signed-off-by: Steven Rostedt (VMware)

tracing: Add synth event generation test module

2020-01-30T14:46:28+00:00

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 
Signed-off-by: Tom Zanussi 
Signed-off-by: Steven Rostedt (VMware)

tracing/boot: Add boot-time tracing

2020-01-13T18:19:41+00:00

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 
Signed-off-by: Steven Rostedt (VMware)

tracing: Introduce trace event injection

2019-12-02T16:07:00+00:00

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: 
 => 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 
Signed-off-by: Cong Wang 
Signed-off-by: Steven Rostedt (VMware)