linux-toradex.git/kernel/trace/trace_uprobe.c, branch v3.15-rc6

tracing/uprobes: Fix uprobe_cpu_buffer memory leak

2014-04-17T14:44:42+00:00

Forgot to free uprobe_cpu_buffer percpu page in uprobe_buffer_disable().

Link: http://lkml.kernel.org/p/534F8B3F.1090407@huawei.com

Cc: stable@vger.kernel.org # v3.14+
Acked-by: Namhyung Kim 
Signed-off-by: zhangwei(Jovi) 
Signed-off-by: Steven Rostedt

tracepoint: Use struct pointer instead of name hash for reg/unreg tracepoints

2014-04-09T00:43:28+00:00

Register/unregister tracepoint probes with struct tracepoint pointer
rather than tracepoint name.

This change, which vastly simplifies tracepoint.c, has been proposed by
Steven Rostedt. It also removes 8.8kB (mostly of text) to the vmlinux
size.

From this point on, the tracers need to pass a struct tracepoint pointer
to probe register/unregister. A probe can now only be connected to a
tracepoint that exists. Moreover, tracers are responsible for
unregistering the probe before the module containing its associated
tracepoint is unloaded.

   text    data     bss     dec     hex filename
10443444        4282528 10391552        25117524        17f4354 vmlinux.orig
10434930        4282848 10391552        25109330        17f2352 vmlinux

Link: http://lkml.kernel.org/r/1396992381-23785-2-git-send-email-mathieu.desnoyers@efficios.com

CC: Ingo Molnar 
CC: Frederic Weisbecker 
CC: Andrew Morton 
CC: Frank Ch. Eigler 
CC: Johannes Berg 
Signed-off-by: Mathieu Desnoyers 
[ SDR - fixed return val in void func in tracepoint_module_going() ]
Signed-off-by: Steven Rostedt

tracing/uprobes: Support mix of ftrace and perf

2014-02-20T17:30:11+00:00

It seems there's no reason to prevent mixed used of ftrace and perf
for a single uprobe event.  At least the kprobes already support it.

Link: http://lkml.kernel.org/r/1389946120-19610-6-git-send-email-namhyung@kernel.org

Reviewed-by: Masami Hiramatsu 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Oleg Nesterov 
Cc: Srikar Dronamraju 
Cc: zhangwei(Jovi) 
Signed-off-by: Namhyung Kim 
Signed-off-by: Steven Rostedt

tracing/uprobes: Support event triggering

2014-02-20T17:30:10+00:00

Add support for event triggering to uprobes.  This is same as kprobes
support added by Tom (plus cleanup by Steven).

Link: http://lkml.kernel.org/r/1389946120-19610-5-git-send-email-namhyung@kernel.org

Reviewed-by: Masami Hiramatsu 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Oleg Nesterov 
Cc: Srikar Dronamraju 
Cc: zhangwei(Jovi) 
Cc: Tom Zanussi 
Signed-off-by: Namhyung Kim 
Signed-off-by: Steven Rostedt

tracing/uprobes: Support ftrace_event_file base multibuffer

2014-02-20T17:30:09+00:00

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 
Reviewed-by: Oleg Nesterov 
Cc: Ingo Molnar 
Cc: Frederic Weisbecker 
Cc: Srikar Dronamraju 
Signed-off-by: zhangwei(Jovi) 
Signed-off-by: Namhyung Kim 
Signed-off-by: Steven Rostedt

tracing/uprobes: Move argument fetching to uprobe_dispatcher()

2014-02-20T17:30:09+00:00

A single uprobe event might serve different users like ftrace and
perf.  And this is especially important for upcoming multi buffer
support.  But in this case it'll fetch (same) data from userspace
multiple times.  So move it to the beginning of the dispatcher
function and reuse it for each users.

Link: http://lkml.kernel.org/r/1389946120-19610-3-git-send-email-namhyung@kernel.org

Reviewed-by: Masami Hiramatsu 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Oleg Nesterov 
Cc: Srikar Dronamraju 
Cc: zhangwei(Jovi) 
Signed-off-by: Namhyung Kim 
Signed-off-by: Steven Rostedt

tracing/uprobes: Rename uprobe_{trace,perf}_print() functions

2014-02-20T17:30:08+00:00

The uprobe_{trace,perf}_print functions are misnomers since what they
do is not printing.  There's also a real print function named
print_uprobe_event() so they'll only increase confusion IMHO.

Rename them with double underscores to follow convention of kprobe.

Link: http://lkml.kernel.org/r/1389946120-19610-2-git-send-email-namhyung@kernel.org

Reviewed-by: Masami Hiramatsu 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Oleg Nesterov 
Cc: Srikar Dronamraju 
Signed-off-by: Namhyung Kim 
Signed-off-by: Steven Rostedt

tracing/probes: Fix build break on !CONFIG_KPROBE_EVENT

2014-01-03T20:27:18+00:00

When kprobe-based dynamic event tracer is not enabled, it caused
following build error:

   kernel/built-in.o: In function `traceprobe_update_arg':
   (.text+0x10c8dd): undefined reference to `fetch_symbol_u8'
   kernel/built-in.o: In function `traceprobe_update_arg':
   (.text+0x10c8e9): undefined reference to `fetch_symbol_u16'
   kernel/built-in.o: In function `traceprobe_update_arg':
   (.text+0x10c8f5): undefined reference to `fetch_symbol_u32'
   kernel/built-in.o: In function `traceprobe_update_arg':
   (.text+0x10c901): undefined reference to `fetch_symbol_u64'
   kernel/built-in.o: In function `traceprobe_update_arg':
   (.text+0x10c909): undefined reference to `fetch_symbol_string'
   kernel/built-in.o: In function `traceprobe_update_arg':
   (.text+0x10c913): undefined reference to `fetch_symbol_string_size'
   ...

It was due to the fetch methods are referred from CHECK_FETCH_FUNCS
macro and since it was only defined in trace_kprobe.c.  Move NULL
definition of such fetch functions to the header file.

Note, it also requires CONFIG_BRANCH_PROFILING enabled to trigger
this failure as well. This is because the "fetch_symbol_*" variables
are referenced in a "else if" statement that will only call
update_symbol_cache(), which is a static inline stub function
when CONFIG_KPROBE_EVENT is not enabled. gcc is smart enough
to optimize this "else if" out and that also removes the code that
references the undefined variables.

But when BRANCH_PROFILING is enabled, it fools gcc into keeping
the if statement around and thus references the undefined symbols
and fails to build.

Reported-by: kbuild test robot 
Signed-off-by: Namhyung Kim 
Signed-off-by: Steven Rostedt

tracing/uprobes: Add @+file_offset fetch method

2014-01-03T01:57:05+00:00

Enable to fetch data from a file offset.  Currently it only supports
fetching from same binary uprobe set.  It'll translate the file offset
to a proper virtual address in the process.

The syntax is "@+OFFSET" as it does similar to normal memory fetching
(@ADDR) which does no address translation.

Suggested-by: Oleg Nesterov 
Acked-by: Masami Hiramatsu 
Acked-by: Oleg Nesterov 
Cc: Srikar Dronamraju 
Cc: zhangwei(Jovi) 
Cc: Arnaldo Carvalho de Melo 
Signed-off-by: Namhyung Kim

tracing/uprobes: Fetch args before reserving a ring buffer

2014-01-02T21:17:44+00:00

Fetching from user space should be done in a non-atomic context.  So
use a per-cpu buffer and copy its content to the ring buffer
atomically.  Note that we can migrate during accessing user memory
thus use a per-cpu mutex to protect concurrent accesses.

This is needed since we'll be able to fetch args from an user memory
which can be swapped out.  Before that uprobes could fetch args from
registers only which saved in a kernel space.

While at it, use __get_data_size() and store_trace_args() to reduce
code duplication.  And add struct uprobe_cpu_buffer and its helpers as
suggested by Oleg.

Reviewed-by: Masami Hiramatsu 
Acked-by: Oleg Nesterov 
Cc: Srikar Dronamraju 
Cc: zhangwei(Jovi) 
Cc: Arnaldo Carvalho de Melo 
Signed-off-by: Namhyung Kim