* [for-next][PATCH 1/3] tracing/README: Add event file usage to tracing mini-HOWTO
2014-01-26 4:59 [for-next][PATCH 0/3] tracing: Update to README and a small bug fix Steven Rostedt
@ 2014-01-26 4:59 ` Steven Rostedt
2014-01-26 4:59 ` [for-next][PATCH 2/3] tracing: Fix formatting of trace README file Steven Rostedt
2014-01-26 4:59 ` [for-next][PATCH 3/3] tracing: Check if tracing is enabled in trace_puts() Steven Rostedt
2 siblings, 0 replies; 4+ messages in thread
From: Steven Rostedt @ 2014-01-26 4:59 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Frederic Weisbecker, Andrew Morton, Tom Zanussi
[-- Attachment #1: 0001-tracing-README-Add-event-file-usage-to-tracing-mini-.patch --]
[-- Type: text/plain, Size: 3831 bytes --]
From: Tom Zanussi <tom.zanussi@linux.intel.com>
It would be useful to have a cheat-sheet for everything under
tracing/events/ alongside the existing text describing the other files
in the tracing/ dir.
Add short descriptions of the directories and files under events/
along with examples, similar to the existing text for the other files
in tracing/.
Also clean up a few minor alignment problems noticed when adding the
new text.
Link: http://lkml.kernel.org/r/1389993104.3040.445.camel@empanada
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace.c | 37 ++++++++++++++++++++++++++++++++++---
1 file changed, 34 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 20c755e..2ced5e5 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3523,9 +3523,9 @@ static const char readme_msg[] =
#ifdef CONFIG_DYNAMIC_FTRACE
"\n available_filter_functions - list of functions that can be filtered on\n"
" set_ftrace_filter\t- echo function name in here to only trace these functions\n"
- " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
- " modules: Can select a group via module\n"
- " Format: :mod:<module-name>\n"
+ " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
+ " modules: Can select a group via module\n"
+ " Format: :mod:<module-name>\n"
" example: echo :mod:ext3 > set_ftrace_filter\n"
" triggers: a command to perform when function is hit\n"
" Format: <function>:<trigger>[:count]\n"
@@ -3573,6 +3573,37 @@ static const char readme_msg[] =
" stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n"
#endif
#endif /* CONFIG_STACK_TRACER */
+ " events/\t\t- Directory containing all trace event subsystems:\n"
+ " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
+ " events/<system>/\t- Directory containing all trace events for <system>:\n"
+ " enable\t\t- Write 0/1 to enable/disable tracing of all <system> events\n"
+ " filter\t\t- If set, only events passing filter are traced\n"
+ " events/<system>/<event>/\t- Directory containing control files for <event>:\n"
+ " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
+ " filter\t\t- If set, only events passing filter are traced\n"
+ " trigger\t\t- If set, a command to perform when event is hit\n"
+ " Format: <trigger>[:count][if <filter>]\n"
+ " trigger: traceon, traceoff\n"
+ " enable_event:<system>:<event>\n"
+ " disable_event:<system>:<event>\n"
+#ifdef CONFIG_STACKTRACE
+ " stacktrace\n"
+#endif
+#ifdef CONFIG_TRACER_SNAPSHOT
+ " snapshot\n"
+#endif
+ " example: echo traceoff > events/block/block_unplug/trigger\n"
+ " echo traceoff:3 > events/block/block_unplug/trigger\n"
+ " echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > events/block/block_unplug/trigger\n"
+ " The first disables tracing every time block_unplug is hit.\n"
+ " The second disables tracing the first 3 times block_unplug is hit.\n"
+ " The third enables the kmalloc event the first 3 times block_unplug\n"
+ " is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
+ " To remove a trigger without a count:\n"
+ " echo '!<trigger> > <system>/<event>/trigger\n"
+ " To remove a trigger with a count:\n"
+ " echo '!<trigger>:0 > <system>/<event>/trigger\n"
+ " Filters can be ignored when removing a trigger.\n"
;
static ssize_t
--
1.8.4.3
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [for-next][PATCH 2/3] tracing: Fix formatting of trace README file
2014-01-26 4:59 [for-next][PATCH 0/3] tracing: Update to README and a small bug fix Steven Rostedt
2014-01-26 4:59 ` [for-next][PATCH 1/3] tracing/README: Add event file usage to tracing mini-HOWTO Steven Rostedt
@ 2014-01-26 4:59 ` Steven Rostedt
2014-01-26 4:59 ` [for-next][PATCH 3/3] tracing: Check if tracing is enabled in trace_puts() Steven Rostedt
2 siblings, 0 replies; 4+ messages in thread
From: Steven Rostedt @ 2014-01-26 4:59 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Frederic Weisbecker, Andrew Morton
[-- Attachment #1: 0002-tracing-Fix-formatting-of-trace-README-file.patch --]
[-- Type: text/plain, Size: 9262 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Fix the formatting of the README file in the trace debugfs to fit in
an 80 character window.
Also add a comment about the event trigger counter with regards to
traceon and traceoff.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace.c | 116 ++++++++++++++++++++++++++++-----------------------
1 file changed, 64 insertions(+), 52 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2ced5e5..7857ea9 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3519,91 +3519,103 @@ static const char readme_msg[] =
" instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
"\t\t\t Remove sub-buffer with rmdir\n"
" trace_options\t\t- Set format or modify how tracing happens\n"
- "\t\t\t Disable an option by adding a suffix 'no' to the option name\n"
+ "\t\t\t Disable an option by adding a suffix 'no' to the\n"
+ "\t\t\t option name\n"
#ifdef CONFIG_DYNAMIC_FTRACE
"\n available_filter_functions - list of functions that can be filtered on\n"
- " set_ftrace_filter\t- echo function name in here to only trace these functions\n"
- " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
- " modules: Can select a group via module\n"
- " Format: :mod:<module-name>\n"
- " example: echo :mod:ext3 > set_ftrace_filter\n"
- " triggers: a command to perform when function is hit\n"
- " Format: <function>:<trigger>[:count]\n"
- " trigger: traceon, traceoff\n"
- " enable_event:<system>:<event>\n"
- " disable_event:<system>:<event>\n"
+ " set_ftrace_filter\t- echo function name in here to only trace these\n"
+ "\t\t\t functions\n"
+ "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
+ "\t modules: Can select a group via module\n"
+ "\t Format: :mod:<module-name>\n"
+ "\t example: echo :mod:ext3 > set_ftrace_filter\n"
+ "\t triggers: a command to perform when function is hit\n"
+ "\t Format: <function>:<trigger>[:count]\n"
+ "\t trigger: traceon, traceoff\n"
+ "\t\t enable_event:<system>:<event>\n"
+ "\t\t disable_event:<system>:<event>\n"
#ifdef CONFIG_STACKTRACE
- " stacktrace\n"
+ "\t\t stacktrace\n"
#endif
#ifdef CONFIG_TRACER_SNAPSHOT
- " snapshot\n"
+ "\t\t snapshot\n"
#endif
- " example: echo do_fault:traceoff > set_ftrace_filter\n"
- " echo do_trap:traceoff:3 > set_ftrace_filter\n"
- " The first one will disable tracing every time do_fault is hit\n"
- " The second will disable tracing at most 3 times when do_trap is hit\n"
- " The first time do trap is hit and it disables tracing, the counter\n"
- " will decrement to 2. If tracing is already disabled, the counter\n"
- " will not decrement. It only decrements when the trigger did work\n"
- " To remove trigger without count:\n"
- " echo '!<function>:<trigger> > set_ftrace_filter\n"
- " To remove trigger with a count:\n"
- " echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
+ "\t example: echo do_fault:traceoff > set_ftrace_filter\n"
+ "\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
+ "\t The first one will disable tracing every time do_fault is hit\n"
+ "\t The second will disable tracing at most 3 times when do_trap is hit\n"
+ "\t The first time do trap is hit and it disables tracing, the\n"
+ "\t counter will decrement to 2. If tracing is already disabled,\n"
+ "\t the counter will not decrement. It only decrements when the\n"
+ "\t trigger did work\n"
+ "\t To remove trigger without count:\n"
+ "\t echo '!<function>:<trigger> > set_ftrace_filter\n"
+ "\t To remove trigger with a count:\n"
+ "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
" set_ftrace_notrace\t- echo function name in here to never trace.\n"
- " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
- " modules: Can select a group via module command :mod:\n"
- " Does not accept triggers\n"
+ "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
+ "\t modules: Can select a group via module command :mod:\n"
+ "\t Does not accept triggers\n"
#endif /* CONFIG_DYNAMIC_FTRACE */
#ifdef CONFIG_FUNCTION_TRACER
- " set_ftrace_pid\t- Write pid(s) to only function trace those pids (function)\n"
+ " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
+ "\t\t (function)\n"
#endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
" set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
" max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
#endif
#ifdef CONFIG_TRACER_SNAPSHOT
- "\n snapshot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n"
- "\t\t\t Read the contents for more information\n"
+ "\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
+ "\t\t\t snapshot buffer. Read the contents for more\n"
+ "\t\t\t information\n"
#endif
#ifdef CONFIG_STACK_TRACER
" stack_trace\t\t- Shows the max stack trace when active\n"
" stack_max_size\t- Shows current max stack size that was traced\n"
- "\t\t\t Write into this file to reset the max size (trigger a new trace)\n"
+ "\t\t\t Write into this file to reset the max size (trigger a\n"
+ "\t\t\t new trace)\n"
#ifdef CONFIG_DYNAMIC_FTRACE
- " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n"
+ " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
+ "\t\t\t traces\n"
#endif
#endif /* CONFIG_STACK_TRACER */
" events/\t\t- Directory containing all trace event subsystems:\n"
" enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
" events/<system>/\t- Directory containing all trace events for <system>:\n"
- " enable\t\t- Write 0/1 to enable/disable tracing of all <system> events\n"
+ " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
+ "\t\t\t events\n"
" filter\t\t- If set, only events passing filter are traced\n"
- " events/<system>/<event>/\t- Directory containing control files for <event>:\n"
+ " events/<system>/<event>/\t- Directory containing control files for\n"
+ "\t\t\t <event>:\n"
" enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
" filter\t\t- If set, only events passing filter are traced\n"
" trigger\t\t- If set, a command to perform when event is hit\n"
- " Format: <trigger>[:count][if <filter>]\n"
- " trigger: traceon, traceoff\n"
- " enable_event:<system>:<event>\n"
- " disable_event:<system>:<event>\n"
+ "\t Format: <trigger>[:count][if <filter>]\n"
+ "\t trigger: traceon, traceoff\n"
+ "\t enable_event:<system>:<event>\n"
+ "\t disable_event:<system>:<event>\n"
#ifdef CONFIG_STACKTRACE
- " stacktrace\n"
+ "\t\t stacktrace\n"
#endif
#ifdef CONFIG_TRACER_SNAPSHOT
- " snapshot\n"
+ "\t\t snapshot\n"
#endif
- " example: echo traceoff > events/block/block_unplug/trigger\n"
- " echo traceoff:3 > events/block/block_unplug/trigger\n"
- " echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > events/block/block_unplug/trigger\n"
- " The first disables tracing every time block_unplug is hit.\n"
- " The second disables tracing the first 3 times block_unplug is hit.\n"
- " The third enables the kmalloc event the first 3 times block_unplug\n"
- " is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
- " To remove a trigger without a count:\n"
- " echo '!<trigger> > <system>/<event>/trigger\n"
- " To remove a trigger with a count:\n"
- " echo '!<trigger>:0 > <system>/<event>/trigger\n"
- " Filters can be ignored when removing a trigger.\n"
+ "\t example: echo traceoff > events/block/block_unplug/trigger\n"
+ "\t echo traceoff:3 > events/block/block_unplug/trigger\n"
+ "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
+ "\t events/block/block_unplug/trigger\n"
+ "\t The first disables tracing every time block_unplug is hit.\n"
+ "\t The second disables tracing the first 3 times block_unplug is hit.\n"
+ "\t The third enables the kmalloc event the first 3 times block_unplug\n"
+ "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
+ "\t Like function triggers, the counter is only decremented if it\n"
+ "\t enabled or disabled tracing.\n"
+ "\t To remove a trigger without a count:\n"
+ "\t echo '!<trigger> > <system>/<event>/trigger\n"
+ "\t To remove a trigger with a count:\n"
+ "\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
+ "\t Filters can be ignored when removing a trigger.\n"
;
static ssize_t
--
1.8.4.3
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [for-next][PATCH 3/3] tracing: Check if tracing is enabled in trace_puts()
2014-01-26 4:59 [for-next][PATCH 0/3] tracing: Update to README and a small bug fix Steven Rostedt
2014-01-26 4:59 ` [for-next][PATCH 1/3] tracing/README: Add event file usage to tracing mini-HOWTO Steven Rostedt
2014-01-26 4:59 ` [for-next][PATCH 2/3] tracing: Fix formatting of trace README file Steven Rostedt
@ 2014-01-26 4:59 ` Steven Rostedt
2 siblings, 0 replies; 4+ messages in thread
From: Steven Rostedt @ 2014-01-26 4:59 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Frederic Weisbecker, Andrew Morton
[-- Attachment #1: 0003-tracing-Check-if-tracing-is-enabled-in-trace_puts.patch --]
[-- Type: text/plain, Size: 1355 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
If trace_puts() is used very early in boot up, it can crash the machine
if it is called before the ring buffer is allocated. If a trace_printk()
is used with no arguments, then it will be converted into a trace_puts()
and suffer the same fate.
Cc: stable@vger.kernel.org # 3.10+
Fixes: 09ae72348ecc "tracing: Add trace_puts() for even faster trace_printk() tracing"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7857ea9..815c878 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -455,6 +455,9 @@ int __trace_puts(unsigned long ip, const char *str, int size)
unsigned long irq_flags;
int alloc;
+ if (unlikely(tracing_selftest_running || tracing_disabled))
+ return 0;
+
alloc = sizeof(*entry) + size + 2; /* possible \n added */
local_save_flags(irq_flags);
@@ -495,6 +498,9 @@ int __trace_bputs(unsigned long ip, const char *str)
unsigned long irq_flags;
int size = sizeof(struct bputs_entry);
+ if (unlikely(tracing_selftest_running || tracing_disabled))
+ return 0;
+
local_save_flags(irq_flags);
buffer = global_trace.trace_buffer.buffer;
event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
--
1.8.4.3
^ permalink raw reply related [flat|nested] 4+ messages in thread