Commit Graph

4337 Commits

Author SHA1 Message Date
Tom Zanussi
3843083772 tracing: Check that number of vals matches number of synth event fields
Commit 7276531d4036('tracing: Consolidate trace() functions')
inadvertently dropped the synth_event_trace() and
synth_event_trace_array() checks that verify the number of values
passed in matches the number of fields in the synthetic event being
traced, so add them back.

Link: http://lkml.kernel.org/r/32819cac708714693669e0dfe10fe9d935e94a16.1581720155.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-20 16:24:17 -05:00
Tom Zanussi
1d9d4c9019 tracing: Make synth_event trace functions endian-correct
synth_event_trace(), synth_event_trace_array() and
__synth_event_add_val() write directly into the trace buffer and need
to take endianness into account, like trace_event_raw_event_synth()
does.

Link: http://lkml.kernel.org/r/2011354355e405af9c9d28abba430d1f5ff7771a.1581720155.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-20 16:24:17 -05:00
Tom Zanussi
279eef0531 tracing: Make sure synth_event_trace() example always uses u64
synth_event_trace() is the varargs version of synth_event_trace_array(),
which takes an array of u64, as do synth_event_add_val() et al.

To not only be consistent with those, but also to address the fact
that synth_event_trace() expects every arg to be of the same type
since it doesn't also pass in e.g. a format string, the caller needs
to make sure all args are of the same type, u64.  u64 is used because
it needs to accomodate the largest type available in synthetic events,
which is u64.

This fixes the bug reported by the kernel test robot/Rong Chen.

Link: https://lore.kernel.org/lkml/20200212113444.GS12867@shao2-debian/
Link: http://lkml.kernel.org/r/894c4e955558b521210ee0642ba194a9e603354c.1581720155.git.zanussi@kernel.org

Fixes: 9fe41efaca ("tracing: Add synth event generation test module")
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-20 16:24:17 -05:00
Tom Zanussi
7276531d40 tracing: Consolidate trace() functions
Move the checking, buffer reserve and buffer commit code in
synth_event_trace_start/end() into inline functions
__synth_event_trace_start/end() so they can also be used by
synth_event_trace() and synth_event_trace_array(), and then have all
those functions use them.

Also, change synth_event_trace_state.enabled to disabled so it only
needs to be set if the event is disabled, which is not normally the
case.

Link: http://lkml.kernel.org/r/b1f3108d0f450e58192955a300e31d0405ab4149.1581374549.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-10 22:00:21 -05:00
Tom Zanussi
0c62f6cd9e tracing: Don't return -EINVAL when tracing soft disabled synth events
There's no reason to return -EINVAL when tracing a synthetic event if
it's soft disabled - treat it the same as if it were hard disabled and
return normally.

Have synth_event_trace() and synth_event_trace_array() just return
normally, and have synth_event_trace_start set the trace state to
disabled and return.

Link: http://lkml.kernel.org/r/df5d02a1625aff97c9866506c5bada6a069982ba.1581374549.git.zanussi@kernel.org

Fixes: 8dcc53ad95 ("tracing: Add synth_event_trace() and related functions")
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-10 22:00:13 -05:00
Tom Zanussi
d090409abb tracing: Add missing nest end to synth_event_trace_start() error case
If the ring_buffer reserve in synth_event_trace_start() fails, the
matching ring_buffer_nest_end() should be called in the error code,
since nothing else will ever call it in this case.

Link: http://lkml.kernel.org/r/20abc444b3eeff76425f895815380abe7aa53ff8.1581374549.git.zanussi@kernel.org

Fixes: 8dcc53ad95 ("tracing: Add synth_event_trace() and related functions")
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-10 21:58:19 -05:00
Gustavo A. R. Silva
10f129cb59 tracing/kprobe: Fix uninitialized variable bug
There is a potential execution path in which variable *ret* is returned
without being properly initialized, previously.

Fix this by initializing variable *ret* to 0.

Link: http://lkml.kernel.org/r/20200205223404.GA3379@embeddedor

Addresses-Coverity-ID: 1491142 ("Uninitialized scalar variable")
Fixes: 2a588dd1d5 ("tracing: Add kprobe event command generation functions")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-10 12:07:42 -05:00
Steven Rostedt (VMware)
54a16ff6f2 ftrace: Protect ftrace_graph_hash with ftrace_sync
As function_graph tracer can run when RCU is not "watching", it can not be
protected by synchronize_rcu() it requires running a task on each CPU before
it can be freed. Calling schedule_on_each_cpu(ftrace_sync) needs to be used.

Link: https://lore.kernel.org/r/20200205131110.GT2935@paulmck-ThinkPad-P72

Cc: stable@vger.kernel.org
Fixes: b9b0c831be ("ftrace: Convert graph filter to use hash tables")
Reported-by: "Paul E. McKenney" <paulmck@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-05 17:16:42 -05:00
Steven Rostedt (VMware)
16052dd5bd ftrace: Add comment to why rcu_dereference_sched() is open coded
Because the function graph tracer can execute in sections where RCU is not
"watching", the rcu_dereference_sched() for the has needs to be open coded.
This is fine because the RCU "flavor" of the ftrace hash is protected by
its own RCU handling (it does its own little synchronization on every CPU
and does not rely on RCU sched).

Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-05 17:15:57 -05:00
Amol Grover
fd0e6852c4 tracing: Annotate ftrace_graph_notrace_hash pointer with __rcu
Fix following instances of sparse error
kernel/trace/ftrace.c:5667:29: error: incompatible types in comparison
kernel/trace/ftrace.c:5813:21: error: incompatible types in comparison
kernel/trace/ftrace.c:5868:36: error: incompatible types in comparison
kernel/trace/ftrace.c:5870:25: error: incompatible types in comparison

Use rcu_dereference_protected to dereference the newly annotated pointer.

Link: http://lkml.kernel.org/r/20200205055701.30195-1-frextrite@gmail.com

Signed-off-by: Amol Grover <frextrite@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-05 17:14:37 -05:00
Amol Grover
24a9729f83 tracing: Annotate ftrace_graph_hash pointer with __rcu
Fix following instances of sparse error
kernel/trace/ftrace.c:5664:29: error: incompatible types in comparison
kernel/trace/ftrace.c:5785:21: error: incompatible types in comparison
kernel/trace/ftrace.c:5864:36: error: incompatible types in comparison
kernel/trace/ftrace.c:5866:25: error: incompatible types in comparison

Use rcu_dereference_protected to access the __rcu annotated pointer.

Link: http://lkml.kernel.org/r/20200201072703.17330-1-frextrite@gmail.com

Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Amol Grover <frextrite@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-05 17:14:26 -05:00
Tom Zanussi
2b90927c77 tracing: Use seq_buf for building dynevent_cmd string
The dynevent_cmd commands that build up the command string don't need
to do that themselves - there's a seq_buf facility that does pretty
much the same thing those command are doing manually, so use it
instead.

Link: http://lkml.kernel.org/r/eb8a6e835c964d0ab8a38cbf5ffa60746b54a465.1580506712.git.zanussi@kernel.org

Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-01 13:10:15 -05:00
Tom Zanussi
e9260f6257 tracing: Remove useless code in dynevent_arg_pair_add()
The final addition to q is unnecessary, since q isn't ever used
afterwards.

Link: http://lkml.kernel.org/r/7880a1268217886cdba7035526650195668da856.1580506712.git.zanussi@kernel.org

Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-01 13:09:42 -05:00
Tom Zanussi
74403b6c50 tracing: Remove check_arg() callbacks from dynevent args
It's kind of strange to have check_arg() callbacks as part of the arg
objects themselves; it makes more sense to just pass these in when the
args are added instead.

Remove the check_arg() callbacks from those objects which also means
removing the check_arg() args from the init functions, adding them to
the add functions and fixing up existing callers.

Link: http://lkml.kernel.org/r/c7708d6f177fcbe1a36b6e4e8e150907df0fa5d2.1580506712.git.zanussi@kernel.org

Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-01 13:09:23 -05:00
Tom Zanussi
249d7b2ef6 tracing: Consolidate some synth_event_trace code
The synth_event trace code contains some almost identical functions
and some small functions that are called only once - consolidate the
common code into single functions and fold in the small functions to
simplify the code overall.

Link: http://lkml.kernel.org/r/d1c8d8ad124a653b7543afe801d38c199ca5c20e.1580506712.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-31 18:35:17 -05:00
Tom Zanussi
d380dcde9a tracing: Fix now invalid var_ref_vals assumption in trace action
The patch 'tracing: Fix histogram code when expression has same var as
value' added code to return an existing variable reference when
creating a new variable reference, which resulted in var_ref_vals
slots being reused instead of being duplicated.

The implementation of the trace action assumes that the end of the
var_ref_vals array starting at action_data.var_ref_idx corresponds to
the values that will be assigned to the trace params. The patch
mentioned above invalidates that assumption, which means that each
param needs to explicitly specify its index into var_ref_vals.

This fix changes action_data.var_ref_idx to an array of var ref
indexes to account for that.

Link: https://lore.kernel.org/r/1580335695.6220.8.camel@kernel.org

Fixes: 8bcebc77e8 ("tracing: Fix histogram code when expression has same var as value")
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-31 12:59:26 -05:00
Tom Zanussi
fdeb1aca28 tracing: Change trace_boot to use synth_event interface
Have trace_boot_add_synth_event() use the synth_event interface.

Also, rename synth_event_run_cmd() to synth_event_run_command() now
that trace_boot's version is gone.

Link: http://lkml.kernel.org/r/94f1fa0e31846d0bddca916b8663404b20559e34.1580323897.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>
2020-01-31 12:59:26 -05:00
Steven Rostedt (VMware)
1e837945a8 tracing: Move tracing selftests to bottom of menu
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>
2020-01-30 09:46:29 -05:00
Steven Rostedt (VMware)
21b3ce3063 tracing: Move mmio tracer config up with the other tracers
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>
2020-01-30 09:46:29 -05:00
Steven Rostedt (VMware)
a48fc4f5f1 tracing: Move tracing test module configs together
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>
2020-01-30 09:46:29 -05:00
Steven Rostedt (VMware)
61778cd70c tracing: Move all function tracing configs together
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>
2020-01-30 09:46:29 -05:00
Tom Zanussi
64836248dd tracing: Add kprobe event command generation test module
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>
2020-01-30 09:46:28 -05:00
Tom Zanussi
29a1548105 tracing: Change trace_boot to use kprobe_event interface
Have trace_boot_add_kprobe_event() use the kprobe_event interface.

Also, rename kprobe_event_run_cmd() to kprobe_event_run_command() now
that trace_boot's version is gone.

Link: http://lkml.kernel.org/r/af5429d11291ab1e9a85a0ff944af3b2bcf193c7.1580323897.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>
2020-01-30 09:46:28 -05:00
Tom Zanussi
2a588dd1d5 tracing: Add kprobe event command generation functions
Add functions used to generate kprobe event commands, built on top of
the dynevent_cmd interface.

kprobe_event_gen_cmd_start() is used to create a kprobe event command
using a variable arg list, and kretprobe_event_gen_cmd_start() does
the same for kretprobe event commands.  kprobe_event_add_fields() can
be used to add single fields one by one or as a group.  Once all
desired fields are added, kprobe_event_gen_cmd_end() or
kretprobe_event_gen_cmd_end() respectively are used to actually
execute the command and create the event.

Link: http://lkml.kernel.org/r/95cc4696502bb6017f9126f306a45ad19b4cc14f.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>
2020-01-30 09:46:28 -05:00
Tom Zanussi
9fe41efaca tracing: Add synth event generation test module
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>
2020-01-30 09:46:28 -05:00
Tom Zanussi
8dcc53ad95 tracing: Add synth_event_trace() and related functions
Add an exported function named synth_event_trace(), allowing modules
or other kernel code to trace synthetic events.

Also added are several functions that allow the same functionality to
be broken out in a piecewise fashion, which are useful in situations
where tracing an event from a full array of values would be
cumbersome.  Those functions are synth_event_trace_start/end() and
synth_event_add_(next)_val().

Link: http://lkml.kernel.org/r/7a84de5f1854acf4144b57efe835ca645afa764f.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>
2020-01-30 09:46:28 -05:00
Tom Zanussi
35ca5207c2 tracing: Add synthetic event command generation functions
Add functions used to generate synthetic event commands, built on top
of the dynevent_cmd interface.

synth_event_gen_cmd_start() is used to create a synthetic event
command using a variable arg list and
synth_event_gen_cmd_array_start() does the same thing but using an
array of field descriptors.  synth_event_add_field(),
synth_event_add_field_str() and synth_event_add_fields() can be used
to add single fields one by one or as a group.  Once all desired
fields are added, synth_event_gen_cmd_end() is used to actually
execute the command and create the event.

synth_event_create() does everything, including creating the event, in
a single call.

Link: http://lkml.kernel.org/r/38fef702fad5ef208009f459552f34a94befd860.1580323897.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>
2020-01-30 09:46:28 -05:00
Tom Zanussi
86c5426bad tracing: Add dynamic event command creation interface
Add an interface used to build up dynamic event creation commands,
such as synthetic and kprobe events.  Interfaces specific to those
particular types of events and others can be built on top of this
interface.

Command creation is started by first using the dynevent_cmd_init()
function to initialize the dynevent_cmd object.  Following that, args
are appended and optionally checked by the dynevent_arg_add() and
dynevent_arg_pair_add() functions, which use objects representing
arguments and pairs of arguments, initialized respectively by
dynevent_arg_init() and dynevent_arg_pair_init().  Finally, once all
args have been successfully added, the command is finalized and
actually created using dynevent_create().

The code here for actually printing into the dyn_event->cmd buffer
using snprintf() etc was adapted from v4 of Masami's 'tracing/boot:
Add synthetic event support' patch.

Link: http://lkml.kernel.org/r/1f65fa44390b6f238f6036777c3784ced1dcc6a0.1580323897.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-30 09:46:28 -05:00
Tom Zanussi
f5f6b255a2 tracing: Add synth_event_delete()
create_or_delete_synth_event() contains code to delete a synthetic
event, which would be useful on its own - specifically, it would be
useful to allow event-creating modules to call it separately.

Separate out the delete code from that function and create an exported
function named synth_event_delete().

Link: http://lkml.kernel.org/r/050db3b06df7f0a4b8a2922da602d1d879c7c1c2.1580323897.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>
2020-01-30 09:46:28 -05:00
Tom Zanussi
e3e2a2cc9c tracing: Add trace_get/put_event_file()
Add a function to get an event file and prevent it from going away on
module or instance removal.

trace_get_event_file() will find an event file in a given instance (if
instance is NULL, it assumes the top trace array) and return it,
pinning the instance's trace array as well as the event's module, if
applicable, so they won't go away while in use.

trace_put_event_file() does the matching release.

Link: http://lkml.kernel.org/r/bb31ac4bdda168d5ed3c4b5f5a4c8f633e8d9118.1580323897.git.zanussi@kernel.org

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
[ Moved trace_array_put() to end of trace_put_event_file() ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-30 09:46:28 -05:00
Tom Zanussi
89c95fcef1 tracing: Add trace_array_find/_get() to find instance trace arrays
Add a new trace_array_find() function that can be used to find a trace
array given the instance name, and replace existing code that does the
same thing with it.  Also add trace_array_find_get() which does the
same but returns the trace array after upping its refcount.

Also make both available for use outside of trace.c.

Link: http://lkml.kernel.org/r/cb68528c975eba95bee4561ac67dd1499423b2e5.1580323897.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>
2020-01-30 09:46:27 -05:00
Vasily Averin
6722b23e7a trigger_next should increase position index
if seq_file .next fuction does not change position index,
read after some lseek can generate unexpected output.

Without patch:
 # dd bs=30 skip=1 if=/sys/kernel/tracing/events/sched/sched_switch/trigger
 dd: /sys/kernel/tracing/events/sched/sched_switch/trigger: cannot skip to specified offset
 n traceoff snapshot stacktrace enable_event disable_event enable_hist disable_hist hist
 # Available triggers:
 # traceon traceoff snapshot stacktrace enable_event disable_event enable_hist disable_hist hist
 6+1 records in
 6+1 records out
 206 bytes copied, 0.00027916 s, 738 kB/s

Notice the printing of "# Available triggers:..." after the line.

With the patch:
 # dd bs=30 skip=1 if=/sys/kernel/tracing/events/sched/sched_switch/trigger
 dd: /sys/kernel/tracing/events/sched/sched_switch/trigger: cannot skip to specified offset
 n traceoff snapshot stacktrace enable_event disable_event enable_hist disable_hist hist
 2+1 records in
 2+1 records out
 88 bytes copied, 0.000526867 s, 167 kB/s

It only prints the end of the file, and does not restart.

Link: http://lkml.kernel.org/r/3c35ee24-dd3a-8119-9c19-552ed253388a@virtuozzo.com

https://bugzilla.kernel.org/show_bug.cgi?id=206283
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-30 09:46:27 -05:00
Vasily Averin
039958a5f7 tracing: eval_map_next() should always increase position index
if seq_file .next fuction does not change position index,
read after some lseek can generate unexpected output.

Link: http://lkml.kernel.org/r/7ad85b22-1866-977c-db17-88ac438bc764@virtuozzo.com

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
[ This is not a bug fix, it just makes it "technically correct"
  which is why I applied it. NULL is only returned on an anomaly
  which triggers a WARN_ON ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-30 09:46:27 -05:00
Vasily Averin
e4075e8bdf ftrace: fpid_next() should increase position index
if seq_file .next fuction does not change position index,
read after some lseek can generate unexpected output.

Without patch:
 # dd bs=4 skip=1 if=/sys/kernel/tracing/set_ftrace_pid
 dd: /sys/kernel/tracing/set_ftrace_pid: cannot skip to specified offset
 id
 no pid
 2+1 records in
 2+1 records out
 10 bytes copied, 0.000213285 s, 46.9 kB/s

Notice the "id" followed by "no pid".

With the patch:
 # dd bs=4 skip=1 if=/sys/kernel/tracing/set_ftrace_pid
 dd: /sys/kernel/tracing/set_ftrace_pid: cannot skip to specified offset
 id
 0+1 records in
 0+1 records out
 3 bytes copied, 0.000202112 s, 14.8 kB/s

Notice that it only prints "id" and not the "no pid" afterward.

Link: http://lkml.kernel.org/r/4f87c6ad-f114-30bb-8506-c32274ce2992@virtuozzo.com

https://bugzilla.kernel.org/show_bug.cgi?id=206283
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-30 09:46:27 -05:00
Mathieu Desnoyers
64ae572bc7 tracing: Fix sched switch start/stop refcount racy updates
Reading the sched_cmdline_ref and sched_tgid_ref initial state within
tracing_start_sched_switch without holding the sched_register_mutex is
racy against concurrent updates, which can lead to tracepoint probes
being registered more than once (and thus trigger warnings within
tracepoint.c).

[ May be the fix for this bug ]
Link: https://lore.kernel.org/r/000000000000ab6f84056c786b93@google.com

Link: http://lkml.kernel.org/r/20190817141208.15226-1-mathieu.desnoyers@efficios.com

Cc: stable@vger.kernel.org
CC: Steven Rostedt (VMware) <rostedt@goodmis.org>
CC: Joel Fernandes (Google) <joel@joelfernandes.org>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Paul E. McKenney <paulmck@linux.ibm.com>
Reported-by: syzbot+774fddf07b7ab29a1e55@syzkaller.appspotmail.com
Fixes: d914ba37d7 ("tracing: Add support for recording tgid of tasks")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-30 09:46:10 -05:00
Masami Hiramatsu
5c3469cb89 tracing/boot: Move external function declarations to kernel/trace/trace.h
Move external function declarations into kernel/trace/trace.h
from trace_boot.c for tracing subsystem internal use.

Link: http://lkml.kernel.org/r/158029060405.12381.11944554430359702545.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-29 08:49:04 -05:00
Masami Hiramatsu
76a598ec8c tracing/boot: Include required headers and sort it alphabetically
Include some required (but currently indirectly included)
headers and sort it alphabetically.

Link: http://lkml.kernel.org/r/158029059514.12381.6597832266860248781.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-29 08:48:44 -05:00
Tom Zanussi
d0a497066f tracing: Add 'hist:' to hist trigger error log error string
The 'hist:' prefix gets stripped from the command text during command
processing, but should be added back when displaying the command
during error processing.

Not only because it's what should be displayed but also because not
having it means the test cases fail because the caret is miscalculated
by the length of the prefix string.

Link: http://lkml.kernel.org/r/449df721f560042e22382f67574bcc5b4d830d3d.1561743018.git.zanussi@kernel.org

Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-28 23:17:10 -05:00
Tom Zanussi
4de26c8c96 tracing: Add hist trigger error messages for sort specification
Add error codes and messages for all the error paths leading to sort
specification parsing errors.

Link: http://lkml.kernel.org/r/237830dc05e583fbb53664d817a784297bf961be.1561743018.git.zanussi@kernel.org

Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-28 23:16:44 -05:00
Tom Zanussi
b527b638fd tracing: Simplify assignment parsing for hist triggers
In the process of adding better error messages for sorting, I realized
that strsep was being used incorrectly and some of the error paths I
was expecting to be hit weren't and just fell through to the common
invalid key error case.

It also became obvious that for keyword assignments, it wasn't
necessary to save the full assignment and reparse it later, and having
a common empty-assignment check would also make more sense in terms of
error processing.

Change the code to fix these problems and simplify it for new error
message changes in a subsequent patch.

Link: http://lkml.kernel.org/r/1c3ef0b6655deaf345f6faee2584a0298ac2d743.1561743018.git.zanussi@kernel.org

Fixes: e62347d245 ("tracing: Add hist trigger support for user-defined sorting ('sort=' param)")
Fixes: 7ef224d1d0 ("tracing: Add 'hist' event trigger command")
Fixes: a4072fe85b ("tracing: Add a clock attribute for hist triggers")
Reported-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-28 23:16:27 -05:00
Steven Rostedt (VMware)
24589e3a20 tracing: Use pr_err() instead of WARN() for memory failures
As warnings can trigger panics, especially when "panic_on_warn" is set,
memory failure warnings can cause panics and fail fuzz testers that are
stressing memory.

Create a MEM_FAIL() macro to use instead of WARN() in the tracing code
(perhaps this should be a kernel wide macro?), and use that for memory
failure issues. This should stop failing fuzz tests due to warnings.

Link: https://lore.kernel.org/r/CACT4Y+ZP-7np20GVRu3p+eZys9GPtbu+JpfV+HtsufAzvTgJrg@mail.gmail.com

Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-25 10:52:30 -05:00
Steven Rostedt (VMware)
28394da258 tracing: Decrement trace_array when bootconfig creates an instance
The trace_array_get_by_name() creates a ftrace instance and
trace_array_put() is used to remove the reference. Even though the
trace_array_get_by_name() creates the instance, it also adds a reference
count to it, that prevents user space from removing it.

As the bootconfig just creates the instance on boot up, it should still be
used where it can be deleted by user space after boot. A trace_array_put()
is required to let that happen.

Also, change the documentation on trace_array_get_by_name() to make this not
be so confusing.

Link: https://lore.kernel.org/r/20200124205927.76128804@rorschach.local.home

Fixes: 4f712a4d04 ("tracing/boot: Add instance node support")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-24 21:29:13 -05:00
Dan Carpenter
b3f7a6cd49 tracing: Remove unneeded NULL check
We checked "iter->trace" earlier so there is no need to check here.

Link: http://lkml.kernel.org/r/20141122183012.GB6994@mwanda

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
[ Pulled from the archeological digging of my INBOX ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-24 18:22:33 -05:00
Josef Bacik
cbc3b92ce0 tracing: Set kernel_stack's caller size properly
I noticed when trying to use the trace-cmd python interface that reading the raw
buffer wasn't working for kernel_stack events.  This is because it uses a
stubbed version of __dynamic_array that doesn't do the __data_loc trick and
encode the length of the array into the field.  Instead it just shows up as a
size of 0.  So change this to __array and set the len to FTRACE_STACK_ENTRIES
since this is what we actually do in practice and matches how user_stack_trace
works.

Link: http://lkml.kernel.org/r/1411589652-1318-1-git-send-email-jbacik@fb.com

Signed-off-by: Josef Bacik <jbacik@fb.com>
[ Pulled from the archeological digging of my INBOX ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-24 18:09:40 -05:00
Luis Henriques
afccc00f75 tracing: Fix tracing_stat return values in error handling paths
tracing_stat_init() was always returning '0', even on the error paths.  It
now returns -ENODEV if tracing_init_dentry() fails or -ENOMEM if it fails
to created the 'trace_stat' debugfs directory.

Link: http://lkml.kernel.org/r/1410299381-20108-1-git-send-email-luis.henriques@canonical.com

Fixes: ed6f1c996b ("tracing: Check return value of tracing_init_dentry()")
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
[ Pulled from the archeological digging of my INBOX ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-24 18:06:48 -05:00
Steven Rostedt (VMware)
dfb6cd1e65 tracing: Fix very unlikely race of registering two stat tracers
Looking through old emails in my INBOX, I came across a patch from Luis
Henriques that attempted to fix a race of two stat tracers registering the
same stat trace (extremely unlikely, as this is done in the kernel, and
probably doesn't even exist). The submitted patch wasn't quite right as it
needed to deal with clean up a bit better (if two stat tracers were the
same, it would have the same files).

But to make the code cleaner, all we needed to do is to keep the
all_stat_sessions_mutex held for most of the registering function.

Link: http://lkml.kernel.org/r/1410299375-20068-1-git-send-email-luis.henriques@canonical.com

Fixes: 002bb86d8d ("tracing/ftrace: separate events tracing and stats tracing engine")
Reported-by: Luis Henriques <luis.henriques@canonical.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-24 17:54:06 -05:00
Alex Shi
659ded3027 trace/kprobe: Remove unused MAX_KPROBE_CMDLINE_SIZE
This limitation are never lunched from introduce commit 970988e19e
("tracing/kprobe: Add kprobe_event= boot parameter")

Could we remove it if no intention to implement it?

Link: http://lkml.kernel.org/r/1579586075-45132-1-git-send-email-alex.shi@linux.alibaba.com

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-22 07:07:38 -05:00
Steven Rostedt (VMware)
34423f250a tracing: Fix uninitialized buffer var on early exit to trace_vbprintk()
If we exit due to a bad input to trace_printk() (highly unlikely), then the
buffer variable will not be initialized when we unnest the ring buffer.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-22 06:44:50 -05:00
Dan Carpenter
532f49a6f1 tracing/boot: Fix an IS_ERR() vs NULL bug
The trace_array_get_by_name() function doesn't return error pointers,
it returns NULL on error.

Link: http://lkml.kernel.org/r/20200117053007.5h2juv272pokqhtq@kili.mountain

Fixes: 4f712a4d04 ("tracing/boot: Add instance node support")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-21 18:41:39 -05:00
Alex Shi
141597204e tracing: Remove unused TRACE_SEQ_BUF_USED
This macro isn't used from commit 3a161d99c4 ("tracing: Create
seq_buf layer in trace_seq"). so no needs to keep it.

Link: http://lkml.kernel.org/r/1579586086-45543-1-git-send-email-alex.shi@linux.alibaba.com

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-01-21 18:39:54 -05:00