linux-toradex.git/kernel/trace/trace.c, branch v3.10.14

tracing: Change tracing_fops/snapshot_fops to rely on tracing_get_cpu()

2013-08-29T16:47:32+00:00

commit 6484c71cbc170634fa131b6d022d86d61686b88b upstream.

tracing_open() and tracing_snapshot_open() are racy, the memory
inode->i_private points to can be already freed.

Convert these last users of "inode->i_private == trace_cpu" to
use "i_private = trace_array" and rely on tracing_get_cpu().

v2: incorporate the fix from Steven, tracing_release() must not
    blindly dereference file->private_data unless we know that
    the file was opened for reading.

Link: http://lkml.kernel.org/r/20130723152610.GA23737@redhat.com

Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Change tracing_entries_fops to rely on tracing_get_cpu()

2013-08-29T16:47:32+00:00

commit 0bc392ee46d0fd8e6b678457ef71f074f19a03c5 upstream.

tracing_open_generic_tc() is racy, the memory inode->i_private
points to can be already freed.

1. Change its last user, tracing_entries_fops, to use
   tracing_*_generic_tr() instead.

2. Change debugfs_create_file("buffer_size_kb", data) callers
   to pass "data = tr".

3. Change tracing_entries_read() and tracing_entries_write() to
   use tracing_get_cpu().

4. Kill the no longer used tracing_open_generic_tc() and
   tracing_release_generic_tc().

Link: http://lkml.kernel.org/r/20130723152606.GA23730@redhat.com

Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Change tracing_stats_fops to rely on tracing_get_cpu()

2013-08-29T16:47:32+00:00

commit 4d3435b8a4c3357695e09c5e7a3bf73a19fca5b0 upstream.

tracing_open_generic_tc() is racy, the memory inode->i_private
points to can be already freed.

1. Change one of its users, tracing_stats_fops, to use
   tracing_*_generic_tr() instead.

2. Change trace_create_cpu_file("stats", data) to pass "data = tr".

3. Change tracing_stats_read() to use tracing_get_cpu().

Link: http://lkml.kernel.org/r/20130723152603.GA23727@redhat.com

Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Change tracing_buffers_fops to rely on tracing_get_cpu()

2013-08-29T16:47:32+00:00

commit 46ef2be0d1d5ccea0c41bb606143586daadd537c upstream.

tracing_buffers_open() is racy, the memory inode->i_private points
to can be already freed.

Change debugfs_create_file("trace_pipe_raw", data) caller to pass
"data = tr", tracing_buffers_open() can use tracing_get_cpu().

Change debugfs_create_file("snapshot_raw_fops", data) caller too,
this file uses tracing_buffers_open/release.

Link: http://lkml.kernel.org/r/20130723152600.GA23720@redhat.com

Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Change tracing_pipe_fops() to rely on tracing_get_cpu()

2013-08-29T16:47:32+00:00

commit 15544209cb0b5312e5220a9337a1fe61d1a1f2d9 upstream.

tracing_open_pipe() is racy, the memory inode->i_private points to
can be already freed.

Change debugfs_create_file("trace_pipe", data) callers to to pass
"data = tr", tracing_open_pipe() can use tracing_get_cpu().

Link: http://lkml.kernel.org/r/20130723152557.GA23717@redhat.com

Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Introduce trace_create_cpu_file() and tracing_get_cpu()

2013-08-29T16:47:32+00:00

commit 649e9c70da6bfbeb563193a35d3424a5aa7c0d38 upstream.

Every "file_operations" used by tracing_init_debugfs_percpu is buggy.
f_op->open/etc does:

	1. struct trace_cpu *tc = inode->i_private;
	   struct trace_array *tr = tc->tr;

	2. trace_array_get(tr) or fail;

	3. do_something(tc);

But tc (and tr) can be already freed before trace_array_get() is called.
And it doesn't matter whether this file is per-cpu or it was created by
init_tracer_debugfs(), free_percpu() or kfree() are equally bad.

Note that even 1. is not safe, the freed memory can be unmapped. But even
if it was safe trace_array_get() can wrongly succeed if we also race with
the next new_instance_create() which can re-allocate the same tr, or tc
was overwritten and ->tr points to the valid tr. In this case 3. uses the
freed/reused memory.

Add the new trivial helper, trace_create_cpu_file() which simply calls
trace_create_file() and encodes "cpu" in "struct inode". Another helper,
tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS.

The patch abuses ->i_cdev to encode the number, it is never used unless
the file is S_ISCHR(). But we could use something else, say, i_bytes or
even ->d_fsdata. In any case this hack is hidden inside these 2 helpers,
it would be trivial to change them if needed.

This patch only changes tracing_init_debugfs_percpu() to use the new
trace_create_cpu_file(), the next patches will change file_operations.

Note: tracing_get_cpu(inode) is always safe but you can't trust the
result unless trace_array_get() was called, without trace_types_lock
which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS.

Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com

Cc: Al Viro 
Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Fix reset of time stamps during trace_clock changes

2013-08-15T05:59:07+00:00

commit 9457158bbc0ee04ecef76862d73eecd8076e9c7b upstream.

Fixed two issues with changing the timestamp clock with trace_clock:

 - The global buffer was reset on instance clock changes. Change this to pass
   the correct per-instance buffer
 - ftrace_now() is used to set buf->time_start in tracing_reset_online_cpus().
   This was incorrect because ftrace_now() used the global buffer's clock to
   return the current time. Change this to use buffer_ftrace_now() which
   returns the current time for the correct per-instance buffer.

Also removed tracing_reset_current() because it is not used anywhere

Link: http://lkml.kernel.org/r/1375493777-17261-2-git-send-email-azl@google.com

Signed-off-by: Alexander Z Lam 
Cc: Vaibhav Nagarnaik 
Cc: David Sharp 
Cc: Alexander Z Lam 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Use flag buffer_disabled for irqsoff tracer

2013-08-15T05:59:07+00:00

commit 10246fa35d4ffdfe472185d4cbf9c2dfd9a9f023 upstream.

If the ring buffer is disabled and the irqsoff tracer records a trace it
will clear out its buffer and lose the data it had previously recorded.

Currently there's a callback when writing to the tracing_of file, but if
tracing is disabled via the function tracer trigger, it will not inform
the irqsoff tracer to stop recording.

By using the "mirror" flag (buffer_disabled) in the trace_array, that keeps
track of the status of the trace_array's buffer, it gives the irqsoff
tracer a fast way to know if it should record a new trace or not.
The flag may be a little behind the real state of the buffer, but it
should not affect the trace too much. It's more important for the irqsoff
tracer to be fast.

Reported-by: Dave Jones 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Make TRACE_ITER_STOP_ON_FREE stop the correct buffer

2013-08-15T05:59:07+00:00

commit 711e124379e0f889e40e2f01d7f5d61936d3cd23 upstream.

Releasing the free_buffer file in an instance causes the global buffer
to be stopped when TRACE_ITER_STOP_ON_FREE is enabled. Operate on the
correct buffer.

Link: http://lkml.kernel.org/r/1375493777-17261-1-git-send-email-azl@google.com

Signed-off-by: Alexander Z Lam 
Cc: Vaibhav Nagarnaik 
Cc: David Sharp 
Cc: Alexander Z Lam 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Fix fields of struct trace_iterator that are zeroed by mistake

2013-08-15T05:59:07+00:00

commit ed5467da0e369e65b247b99eb6403cb79172bcda upstream.

tracing_read_pipe zeros all fields bellow "seq". The declaration contains
a comment about that, but it doesn't help.

The first field is "snapshot", it's true when current open file is
snapshot. Looks obvious, that it should not be zeroed.

The second field is "started". It was converted from cpumask_t to
cpumask_var_t (v2.6.28-4983-g4462344), in other words it was
converted from cpumask to pointer on cpumask.

Currently the reference on "started" memory is lost after the first read
from tracing_read_pipe and a proper object will never be freed.

The "started" is never dereferenced for trace_pipe, because trace_pipe
can't have the TRACE_FILE_ANNOTATE options.

Link: http://lkml.kernel.org/r/1375463803-3085183-1-git-send-email-avagin@openvz.org

Signed-off-by: Andrew Vagin 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman