No architecture uses the "data" parameter in ftrace_dyn_arch_init() in any
way, it just sets the value to 0. And this is used as a return value
in the caller -- ftrace_init, which just checks the retval against
zero.
Note there is also "return 0" in every ftrace_dyn_arch_init. So it is
enough to check the retval and remove all the indirect sets of data on
all archs.
Link: http://lkml.kernel.org/r/1393268401-24379-3-git-send-email-jslaby@suse.cz
Cc: linux-arch@vger.kernel.org
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This fixes expansion of the len argument in __dynamic_array macros.
The previous code from commit 7d536cb3f would not fully evaluate the
expression before multiplying its result by the size of the type.
This went unnoticed because the length stored in the high 16 bits of the
offset (which is the one that was broken here) is only used by
filter_pred_strloc which only acts on strings for which the size of the
type is 1.
Link: http://lkml.kernel.org/r/1393651938-16418-2-git-send-email-filbranden@google.com
Signed-off-by: Filipe Brandenburger <filbranden@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
There's nothing in the module.h header that requires tracepoint.h to be
included, and there may be cases that tracepoint.h may need to include
module.h, which will cause recursive header issues.
But module.h requires seeing HAVE_JUMP_LABEL which is set in jump_label.h
which it just coincidentally gets from tracepoint.h.
Link: http://lkml.kernel.org/r/20140307084712.5c68641a@gandalf.local.home
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Tracepoints were made to allow enabling a tracepoint in a module before that
module was loaded. When a tracepoint is enabled and it does not exist, the
name is stored and will be enabled when the tracepoint is created.
The problem with this approach is that when a tracepoint is enabled when
it expects to be there, it gives no warning that it does not exist.
To add salt to the wound, if a module is added and sets the FORCED flag, which
can happen if it isn't signed properly, the tracepoint code will not enabled
the tracepoints, but they will be created in the debugfs system! When a user
goes to enable the tracepoint, the tracepoint code will not see it existing
and will think it is to be enabled later AND WILL NOT GIVE A WARNING.
The tracing will look like it succeeded but will actually be doing nothing.
This will cause lots of confusion and headaches for developers trying to
figure out why they are not seeing their tracepoints.
Link: http://lkml.kernel.org/r/20140213154507.4040fb06@gandalf.local.home
Reported-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reported-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The functions that assign the contents for the ftrace events are
defined by the TRACE_EVENT() macros. Each event has its own unique
way to assign data to its buffer. When you have over 500 events,
that means there's 500 functions assigning data uniquely for each
event (not really that many, as DECLARE_EVENT_CLASS() and multiple
DEFINE_EVENT()s will only need a single function).
By making helper functions in the core kernel to do some of the work
instead, we can shrink the size of the kernel down a bit.
With a kernel configured with 502 events, the change in size was:
text data bss dec hex filename
12987390 1913504 9785344 24686238 178ae9e /tmp/vmlinux
12959102 1913504 9785344 24657950 178401e /tmp/vmlinux.patched
That's a total of 28288 bytes, which comes down to 56 bytes per event.
Link: http://lkml.kernel.org/r/20120810034708.370808175@goodmis.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The code that shows array fields for events is defined for all events.
This can add up quite a bit when you have over 500 events.
By making helper functions in the core kernel to do the work
instead, we can shrink the size of the kernel down a bit.
With a kernel configured with 502 events, the change in size was:
text data bss dec hex filename
12990946 1913568 9785344 24689858 178bcc2 /tmp/vmlinux
12987390 1913504 9785344 24686238 178ae9e /tmp/vmlinux.patched
That's a total of 3556 bytes, which comes down to 7 bytes per event.
Although it's not much, this code is just called at initialization of
the events.
Link: http://lkml.kernel.org/r/20120810034708.084036335@goodmis.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The code for trace events to format the raw recorded event data
into human readable format in the 'trace' file is repeated for every
event in the system. When you have over 500 events, this can add up
quite a bit.
By making helper functions in the core kernel to do the work
instead, we can shrink the size of the kernel down a bit.
With a kernel configured with 502 events, the change in size was:
text data bss dec hex filename
12991007 1913568 9785344 24689919 178bcff /tmp/vmlinux.orig
12990946 1913568 9785344 24689858 178bcc2 /tmp/vmlinux.patched
Note, this version does not save as much as the version of this patch
I had a few years ago. That is because in the mean time, commit
f71130de5c ("tracing: Add a helper function for event print functions")
did a lot of the work my original patch did. But this change helps
slightly, and is part of a larger clean up to reduce the size much further.
Link: http://lkml.kernel.org/r/20120810034707.378538034@goodmis.org
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Having ftrace_write() return -EPERM on failure, as that's what the callers
return, then we can clean up the code a bit. That is, instead of:
if (ftrace_write(...))
return -EPERM;
return 0;
or
if (ftrace_write(...)) {
ret = -EPERM;
goto_out;
}
We can instead have:
return ftrace_write(...);
or
ret = ftrace_write(...);
if (ret)
goto out;
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
No reason to allocate tp_module structures for modules that have no
tracepoints. This just wastes memory.
Fixes: b75ef8b44b "Tracepoint: Dissociate from module mutex"
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If a failure occurs while modifying ftrace function, it bails out and will
remove the tracepoints to be back to what the code originally was.
There is missing the final sync run across the CPUs after the fix up is done
and before the ftrace int3 handler flag is reset.
Here's the description of the problem:
CPU0 CPU1
---- ----
remove_breakpoint();
modifying_ftrace_code = 0;
[still sees breakpoint]
<takes trap>
[sees modifying_ftrace_code as zero]
[no breakpoint handler]
[goto failed case]
[trap exception - kernel breakpoint, no
handler]
BUG()
Link: http://lkml.kernel.org/r/1393258342-29978-2-git-send-email-pmladek@suse.cz
Fixes: 8a4d0a687a "ftrace: Use breakpoint method to update ftrace caller"
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If a failure occurs while enabling a trace, it bails out and will remove
the tracepoints to be back to what the code originally was. But the fix
up had some bugs in it. By injecting a failure in the code, the fix up
ran to completion, but shortly afterward the system rebooted.
There was two bugs here.
The first was that there was no final sync run across the CPUs after the
fix up was done, and before the ftrace int3 handler flag was reset. That
means that other CPUs could still see the breakpoint and trigger on it
long after the flag was cleared, and the int3 handler would think it was
a spurious interrupt. Worse yet, the int3 handler could hit other breakpoints
because the ftrace int3 handler flag would have prevented the int3 handler
from going further.
Here's a description of the issue:
CPU0 CPU1
---- ----
remove_breakpoint();
modifying_ftrace_code = 0;
[still sees breakpoint]
<takes trap>
[sees modifying_ftrace_code as zero]
[no breakpoint handler]
[goto failed case]
[trap exception - kernel breakpoint, no
handler]
BUG()
The second bug was that the removal of the breakpoints required the
"within()" logic updates instead of accessing the ip address directly.
As the kernel text is mapped read-only when CONFIG_DEBUG_RODATA is set, and
the removal of the breakpoint is a modification of the kernel text.
The ftrace_write() includes the "within()" logic, where as, the
probe_kernel_write() does not. This prevented the breakpoint from being
removed at all.
Link: http://lkml.kernel.org/r/1392650573-3390-1-git-send-email-pmladek@suse.cz
Reported-by: Petr Mladek <pmladek@suse.cz>
Tested-by: Petr Mladek <pmladek@suse.cz>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The ENABLED flag needs to be cleared when a ftrace_ops is unregistered
otherwise it wont be able to be registered again.
This is only for static tracing and does not affect DYNAMIC_FTRACE at
all.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Being able to change the trace clock at boot can be advantageous if
you need a better source of when things happen across CPUs. The default
trace clock is the fastest, but it uses local clocks which may not be
synced across CPUs and it does not let you know when events took place
with respect to events on other CPUs.
The global trace clock can help in this case, and if you do not care
about timings, the counter "clock" is the best, as that is just a simple
atomic counter that is incremented for every event.
Usage is to add "trace_clock=counter" on the kernel command line. You
can replace counter with "global" or any of the clocks listed in
/sys/kernel/debug/tracing/trace_clock
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Appreciated-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Support multi-buffer on uprobe-based dynamic events by
using ftrace_event_file.
This patch is based kprobe-based dynamic events multibuffer
support work initially, commited by Masami(commit 41a7dd420c),
but revised as below:
Oleg changed the kprobe-based multibuffer design from
array-pointers of ftrace_event_file into simple list,
so this patch also change to the list design.
rcu_read_lock/unlock added into uprobe_trace_func/uretprobe_trace_func,
to synchronize with ftrace_event_file list add and delete.
Even though we allow multi-uprobes instances now,
but TP_FLAG_PROFILE/TP_FLAG_TRACE are still mutually exclusive
in probe_event_enable currently, this means we cannot allow
one user is using uprobe-tracer, and another user is using
perf-probe on same uprobe concurrently.
(Perhaps this will be fix in future, kprobe don't have this
limitation now)
Link: http://lkml.kernel.org/r/1389946120-19610-4-git-send-email-namhyung@kernel.org
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Create a "set_ftrace_filter" and "set_ftrace_notrace" files in the instance
directories to let users filter of functions to trace for the given instance.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Jiri Slaby
Filipe Brandenburger
Steven Rostedt (Red Hat)
Steven Rostedt
Petr Mladek
Namhyung Kim
zhangwei(Jovi)