user/sven/linux.git/kernel/trace/trace_events.c, branch v3.2.31

tracing: fix event_subsystem ref counting

2011-12-05T18:28:44Z

Fix a bug introduced by e9dbfae5, which prevents event_subsystem from ever being released. Ref_count was added to keep track of subsystem users, not for counting events. Subsystem is created with ref_count = 1, so there is no need to increment it for every event, we have nr_events for that. Fix this by touching ref_count only when we actually have a new user - subsystem_open(). Cc: stable@vger.kernel.org Signed-off-by: Ilya Dryomov Link: http://lkml.kernel.org/r/1320052062-7846-1-git-send-email-idryomov@gmail.com Signed-off-by: Steven Rostedt

Merge branch 'perf/urgent' into perf/core

2011-07-21T07:29:21Z

Merge reason: pick up the latest fixes - they won't make v3.0. Signed-off-by: Ingo Molnar

tracing: Have "enable" file use refcounts like the "filter" file

2011-07-07T15:22:29Z

The "enable" file for the event system can be removed when a module is unloaded and the event system only has events from that module. As the event system nr_events count goes to zero, it may be freed if its ref_count is also set to zero. Like the "filter" file, the "enable" file may be opened by a task and referenced later, after a module has been unloaded and the events for that event system have been removed. Although the "filter" file referenced the event system structure, the "enable" file only references a pointer to the event system name. Since the name is freed when the event system is removed, it is possible that an access to the "enable" file may reference a freed pointer. Update the "enable" file to use the subsystem_open() routine that the "filter" file uses, to keep a reference to the event system structure while the "enable" file is opened. Cc: Reported-by: Johannes Berg Signed-off-by: Steven Rostedt

tracing: Fix bug when reading system filters on module removal

2011-07-07T15:19:18Z

The event system is freed when its nr_events is set to zero. This happens when a module created an event system and then later the module is removed. Modules may share systems, so the system is allocated when it is created and freed when the modules are unloaded and all the events under the system are removed (nr_events set to zero). The problem arises when a task opened the "filter" file for the system. If the module is unloaded and it removed the last event for that system, the system structure is freed. If the task that opened the filter file accesses the "filter" file after the system has been freed, the system will access an invalid pointer. By adding a ref_count, and using it to keep track of what is using the event system, we can free it after all users are finished with the event system. Cc: Reported-by: Johannes Berg Signed-off-by: Steven Rostedt

tracing: Convert to kstrtoul_from_user

2011-06-15T02:48:50Z

This patch replaces the code for getting an unsigned long from a userspace buffer by a simple call to kstroul_from_user. This makes it easier to read and less error prone. Signed-off-by: Peter Huewe Link: http://lkml.kernel.org/r/1307476707-14762-1-git-send-email-peterhuewe@gmx.de Signed-off-by: Steven Rostedt

tracing: Have event with function tracer check error return

2011-05-26T02:13:39Z

The self tests for event tracer does not check if the function tracing was successfully activated. It needs to before it continues the tests, otherwise the wrong errors may be reported. Signed-off-by: Steven Rostedt

Regression: partial revert "tracing: Remove lock_depth from event entry"

2011-05-06T20:20:59Z

This partially reverts commit e6e1e2593592a8f6f6380496655d8c6f67431266. That commit changed the structure layout of the trace structure, which in turn broke PowerTOP (1.9x generation) quite badly. I appreciate not wanting to expose the variable in question, and PowerTOP was not using it, so I've replaced the variable with just a padding field - that way if in the future a new field is needed it can just use this padding field. Signed-off-by: Arjan van de Ven Signed-off-by: Linus Torvalds

tracing: Export trace_set_clr_event()

2011-03-10T15:34:51Z

Trace events belonging to a module only exists when the module is loaded. Well, we can use trace_set_clr_event funtion to enable some trace event at the module init routine, so that we will not miss something while loading then module. So, Export the trace_set_clr_event function so that module can use it. Signed-off-by: Yuanhan Liu LKML-Reference: <1289196312-25323-1-git-send-email-yuanhan.liu@linux.intel.com> Cc: Steven Rostedt Cc: Frederic Weisbecker Cc: Ingo Molnar Signed-off-by: Steven Rostedt

tracing: Remove lock_depth from event entry

2011-03-10T15:31:48Z

The lock_depth field in the event headers was added as a temporary data point for help in removing the BKL. Now that the BKL is pretty much been removed, we can remove this field. This in turn changes the header from 12 bytes to 8 bytes, removing the 4 byte buffer that gcc would insert if the first field in the data load was 8 bytes in size. Signed-off-by: Steven Rostedt

tracing: Replace trace_event struct array with pointer array

2011-02-03T02:37:13Z

Currently the trace_event structures are placed in the _ftrace_events section, and at link time, the linker makes one large array of all the trace_event structures. On boot up, this array is read (much like the initcall sections) and the events are processed. The problem is that there is no guarantee that gcc will place complex structures nicely together in an array format. Two structures in the same file may be placed awkwardly, because gcc has no clue that they are suppose to be in an array. A hack was used previous to force the alignment to 4, to pack the structures together. But this caused alignment issues with other architectures (sparc). Instead of packing the structures into an array, the structures' addresses are now put into the _ftrace_event section. As pointers are always the natural alignment, gcc should always pack them tightly together (otherwise initcall, extable, etc would also fail). By having the pointers to the structures in the section, we can still iterate the trace_events without causing unnecessary alignment problems with other architectures, or depending on the current behaviour of gcc that will likely change in the future just to tick us kernel developers off a little more. The _ftrace_event section is also moved into the .init.data section as it is now only needed at boot up. Suggested-by: David Miller Cc: Mathieu Desnoyers Acked-by: David S. Miller Signed-off-by: Steven Rostedt