Re: [PATCH v6 00/22] tracing: bootconfig: Boot-time tracing and Extra boot config

Masami Hiramatsu
2020-01-19T14:20:48Z

Hi Steve,

Thanks for pick this series on your tree. I would like to fix some patches
according to Randy's comments. Should I update this series or just incremental
updates on top of your tree?

Thank you,

On Sat, 11 Jan 2020 01:03:20 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Hello,
>
> This is the 6th version of the series for the boot-time tracing.
>
> Previous version is here.
>
> https://lkml.kernel.org/r/157736902773.11126.2531161235817081873.stgit@devnote2
>
> Thanks Steve for reivew. I fixed issues in this version.
>
> - [1/22] Remove "!!" from xbc_node_is_value().
> Redefine xbc_node_is_key() as "!xbc_node_is_value()".
> Fix a memory leak and a bug in __xbc_parse_value().
> Add xbc_destroy_all() to clean up the parsed data.
> Fix to treat comment right after value as a newline.
>
> - [3/22] Fix memory leaks.
> Fix to cleanup old bootconfig on memory before load new one.
> Show applying message.
> Suppress parse error with wrong data in initrd for delete_xbc().
>
> - [4/22] Add some testcases for value parser
> Add a test case for checking delete old bootconfig
>
> - [9/22] Add a note about comment after value.
>
> - [21/22] Fix to depend on CONFIG_DYNAMIC_FTRACE instead
> of CONFIG_FUNCTION_TRACER.
>
> This series can be applied on v5.5-rc5 or directly available at;
>
> https://github.com/mhiramat/linux.git ftrace-boottrace-v6
>
>
> Extra Boot Config
> =================
>
> Extra boot config allows admin to pass a tree-structured key-value
> list when booting up the kernel. This expands the kernel command
> line in an efficient way.
>
> Each key is described as a dot-jointed-words. And user can write
> the key-words in tree stlye. (In this version, the tailing ';'
> becomes optional. See Documentation/admin-guide/bootconfig.rst)
>
> For example,
>
> feature.option.foo = 1
> feature.option.bar = 2
>
> can be also written in
>
> feature.option {
> foo = 1
> bar = 2
> }
>
> or more compact,
>
> feature.option{foo=1;bar=2}
>
> (Note that in both style, the same words are merged automatically
> and make a single tree)
> All values are treated as a string, or array of strings, e.g.
>
> feature.options = "foo", "bar"
>
> User can see the loaded key-value list via /proc/bootconfig.
> The size is limited upto 32KB and 1024 key-words and values
> in total.
>
> Boot with a Boot Config
> =======================
>
> This version doesn't require to modify boot loaders anymore.
> The boot config is loaded with initrd, and there is new "bootconfig"
> command under tools/bootconfig.
> To add (append) a bootconfig file to an initrd, you can use the
> bootconfig command like:
>
> # tools/bootconfig/bootconfig -a your-config /boot/initrd.img-X.Y.Z
>
> This verifies the configuration file too.
>
>
> Boot-time Tracing
> =================
>
> Boot-time tracing supports following boot configs. Please read
> Documentation/trace/boottime-trace.rst for details.
>
> - kernel.dump_on_oops [= MODE]
> - kernel.traceoff_on_warning
> - kernel.tp_printk
> - kernel.fgraph_filters = FILTER[, FILTER2...]
> - kernel.fgraph_notraces = FILTER[, FILTER2...]
> - kernel.fgraph_max_depth = MAX_DEPTH
> - ftrace.[instance.INSTANCE.]options = OPT1[,OPT2...]
> - ftrace.[instance.INSTANCE.]trace_clock = CLOCK
> - ftrace.[instance.INSTANCE.]buffer_size = SIZE
> - ftrace.[instance.INSTANCE.]alloc_snapshot
> - ftrace.[instance.INSTANCE.]cpumask = CPUMASK
> - ftrace.[instance.INSTANCE.]events = EVENT[, EVENT2...]
> - ftrace.[instance.INSTANCE.]tracer = TRACER
> - ftrace.[instance.INSTANCE.]ftrace.filters
> - ftrace.[instance.INSTANCE.]ftrace.notraces
> - ftrace.[instance.INSTANCE.]event.GROUP.EVENT.filter = FILTER
> - ftrace.[instance.INSTANCE.]event.GROUP.EVENT.actions = ACTION[, ACTION2...]
> - ftrace.[instance.INSTANCE.]event.GROUP.EVENT.enable
> - ftrace.[instance.INSTANCE.]event.kprobes.EVENT.probes = PROBE[, PROBE2...]
> - ftrace.[instance.INSTANCE.]event.synthetic.EVENT.fields = FIELD[, FIELD2...]
>
> Kernel and Init Command Line
> ============================
>
> Boot config also supports kernel and init command line parameters
> except for early kernel parameters.
>
> In boot config, all key-values start with "kernel." are automatically
> merged into user passed boot command line, and key-values which
> start with "init." are also passed to init. These options are visible
> on /proc/cmdline.
>
> For example,
>
> kernel {
> audit = on
> audit_backlog_limit = 256
> }
> init.systemd.unified_cgroup_hierarchy = 1
>
>
> Usage
> =====
>
> With this series, we can setup new kprobe and synthetic events, more
> complicated event filters and trigger actions including histogram
> via supplemental kernel cmdline.
>
> We can add filter and actions for each event, define kprobe events,
> and synthetic events with histogram like below.
>
> ftrace.event {
> task.task_newtask {
> filter = "pid < 128"
> enable
> }
> kprobes.vfs_read {
> probes = "vfs_read $arg1 $arg2"
> filter = "common_pid < 200"
> enable
> }
> synthetic.initcall_latency {
> fields = "unsigned long func", "u64 lat"
> actions = "hist:keys=func.sym,lat:vals=lat:sort=lat"
> }
> initcall.initcall_start {
> actions = "hist:keys=func:ts0=common_timestamp.usecs"
> }
> initcall.initcall_finish {
> actions = "hist:keys=func:lat=common_timestamp.usecs-$ts0:onmatch(initcall.initcall_start).initcall_latency(func,$lat)"
> }
> }
>
> Also, this supports "instance" node, which allows us to run several
> tracers for different purpose at once. For example, one tracer is for
> tracing functions start with "user_", and others tracing "kernel_",
> you can write boot config as:
>
> ftrace.instance {
> foo {
> tracer = "function"
> ftrace-filters = "user_*"
> }
> bar {
> tracer = "function"
> ftrace-filters = "function_*"
> }
> }
>
> The instance node also accepts event nodes so that each instance
> can customize its event tracing.
>
> This boot-time trace also supports ftrace kernel parameters.
> For example, following kernel parameters
>
> trace_options=sym-addr trace_event=initcall:* tp_printk trace_buf_size=1M ftrace=function ftrace_filter="vfs*"
>
> it can be written in boot config like below.
>
> ftrace {
> options = sym-addr
> events = "initcall:*"
> tp-printk
> buffer-size = 1MB
> ftrace-filters = "vfs*"
> }
>
> However, since the initialization timing is different, if you need
> to trace very early boot, please use normal kernel parameters.
>
> Some Notes
> ==========
>
> - To align the legacy command line rule, I made the quotes (double
> quotes or single quotes) not able to be escaped.
> Also, this rejects non-printable chars (except for space). Actually
> legacy cmdline accepts any of them, but it might confuse users if
> they put a control code by mistake. Imagine that they put a "\b"
> on it...
>
> - Since it is not easy to write boot-time tracing without any bug
> in bootconfig, a user-helper command will be needed.
> That command will generate a boot config file from current ftrace
> settings, or try to apply given boot config setting to the ftrace.
>
> Thank you,
>
> ---
>
> Masami Hiramatsu (22):
> bootconfig: Add Extra Boot Config support
> bootconfig: Load boot config from the tail of initrd
> tools: bootconfig: Add bootconfig command
> tools: bootconfig: Add bootconfig test script
> proc: bootconfig: Add /proc/bootconfig to show boot config list
> init/main.c: Alloc initcall_command_line in do_initcall() and free it
> bootconfig: init: Allow admin to use bootconfig for kernel command line
> bootconfig: init: Allow admin to use bootconfig for init command line
> Documentation: bootconfig: Add a doc for extended boot config
> tracing: Apply soft-disabled and filter to tracepoints printk
> tracing: kprobes: Output kprobe event to printk buffer
> tracing: kprobes: Register to dynevent earlier stage
> tracing: Accept different type for synthetic event fields
> tracing: Add NULL trace-array check in print_synth_event()
> tracing/boot: Add boot-time tracing
> tracing/boot: Add per-event settings
> tracing/boot Add kprobe event support
> tracing/boot: Add synthetic event support
> tracing/boot: Add instance node support
> tracing/boot: Add cpu_mask option support
> tracing/boot: Add function tracer filter options
> Documentation: tracing: Add boot-time tracing document
>
>
> Documentation/admin-guide/bootconfig.rst | 186 +++++
> Documentation/admin-guide/index.rst | 1
> Documentation/trace/boottime-trace.rst | 184 +++++
> Documentation/trace/index.rst | 1
> MAINTAINERS | 9
> fs/proc/Makefile | 1
> fs/proc/bootconfig.c | 89 ++
> include/linux/bootconfig.h | 224 ++++++
> include/linux/trace_events.h | 1
> init/Kconfig | 12
> init/main.c | 213 +++++
> kernel/trace/Kconfig | 9
> kernel/trace/Makefile | 1
> kernel/trace/trace.c | 63 +-
> kernel/trace/trace_boot.c | 353 +++++++++
> kernel/trace/trace_events.c | 1
> kernel/trace/trace_events_hist.c | 14
> kernel/trace/trace_events_trigger.c | 2
> kernel/trace/trace_kprobe.c | 81 +-
> lib/Kconfig | 3
> lib/Makefile | 2
> lib/bootconfig.c | 803 ++++++++++++++++++++
> tools/Makefile | 11
> tools/bootconfig/.gitignore | 1
> tools/bootconfig/Makefile | 23 +
> tools/bootconfig/include/linux/bootconfig.h | 7
> tools/bootconfig/include/linux/bug.h | 12
> tools/bootconfig/include/linux/ctype.h | 7
> tools/bootconfig/include/linux/errno.h | 7
> tools/bootconfig/include/linux/kernel.h | 18
> tools/bootconfig/include/linux/printk.h | 17
> tools/bootconfig/include/linux/string.h | 32 +
> tools/bootconfig/main.c | 354 +++++++++
> .../samples/bad-array-space-comment.bconf | 5
> tools/bootconfig/samples/bad-array.bconf | 2
> tools/bootconfig/samples/bad-dotword.bconf | 4
> tools/bootconfig/samples/bad-empty.bconf | 1
> tools/bootconfig/samples/bad-keyerror.bconf | 2
> tools/bootconfig/samples/bad-longkey.bconf | 1
> tools/bootconfig/samples/bad-manywords.bconf | 1
> tools/bootconfig/samples/bad-no-keyword.bconf | 2
> tools/bootconfig/samples/bad-nonprintable.bconf | 2
> tools/bootconfig/samples/bad-spaceword.bconf | 2
> tools/bootconfig/samples/bad-tree.bconf | 5
> tools/bootconfig/samples/bad-value.bconf | 3
> tools/bootconfig/samples/escaped.bconf | 3
> .../samples/good-array-space-comment.bconf | 4
> .../samples/good-comment-after-value.bconf | 1
> tools/bootconfig/samples/good-printables.bconf | 2
> tools/bootconfig/samples/good-simple.bconf | 11
> tools/bootconfig/samples/good-single.bconf | 4
> .../samples/good-space-after-value.bconf | 1
> tools/bootconfig/samples/good-tree.bconf | 12
> tools/bootconfig/test-bootconfig.sh | 105 +++
> 54 files changed, 2836 insertions(+), 79 deletions(-)
> create mode 100644 Documentation/admin-guide/bootconfig.rst
> create mode 100644 Documentation/trace/boottime-trace.rst
> create mode 100644 fs/proc/bootconfig.c
> create mode 100644 include/linux/bootconfig.h
> create mode 100644 kernel/trace/trace_boot.c
> create mode 100644 lib/bootconfig.c
> create mode 100644 tools/bootconfig/.gitignore
> create mode 100644 tools/bootconfig/Makefile
> create mode 100644 tools/bootconfig/include/linux/bootconfig.h
> create mode 100644 tools/bootconfig/include/linux/bug.h
> create mode 100644 tools/bootconfig/include/linux/ctype.h
> create mode 100644 tools/bootconfig/include/linux/errno.h
> create mode 100644 tools/bootconfig/include/linux/kernel.h
> create mode 100644 tools/bootconfig/include/linux/printk.h
> create mode 100644 tools/bootconfig/include/linux/string.h
> create mode 100644 tools/bootconfig/main.c
> create mode 100644 tools/bootconfig/samples/bad-array-space-comment.bconf
> create mode 100644 tools/bootconfig/samples/bad-array.bconf
> create mode 100644 tools/bootconfig/samples/bad-dotword.bconf
> create mode 100644 tools/bootconfig/samples/bad-empty.bconf
> create mode 100644 tools/bootconfig/samples/bad-keyerror.bconf
> create mode 100644 tools/bootconfig/samples/bad-longkey.bconf
> create mode 100644 tools/bootconfig/samples/bad-manywords.bconf
> create mode 100644 tools/bootconfig/samples/bad-no-keyword.bconf
> create mode 100644 tools/bootconfig/samples/bad-nonprintable.bconf
> create mode 100644 tools/bootconfig/samples/bad-spaceword.bconf
> create mode 100644 tools/bootconfig/samples/bad-tree.bconf
> create mode 100644 tools/bootconfig/samples/bad-value.bconf
> create mode 100644 tools/bootconfig/samples/escaped.bconf
> create mode 100644 tools/bootconfig/samples/good-array-space-comment.bconf
> create mode 100644 tools/bootconfig/samples/good-comment-after-value.bconf
> create mode 100644 tools/bootconfig/samples/good-printables.bconf
> create mode 100644 tools/bootconfig/samples/good-simple.bconf
> create mode 100644 tools/bootconfig/samples/good-single.bconf
> create mode 100644 tools/bootconfig/samples/good-space-after-value.bconf
> create mode 100644 tools/bootconfig/samples/good-tree.bconf
> create mode 100755 tools/bootconfig/test-bootconfig.sh
>
> --
> Masami Hiramatsu (Linaro) <mhiramat@kernel.org>

--
Masami Hiramatsu <mhiramat@kernel.org>