linux/kernel/trace, branch v3.10.9

tracing: Fix reset of time stamps during trace_clock changes

2013-08-15T05:59:07Z

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

2013-08-15T05:59:07Z

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

2013-08-15T05:59:07Z

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

2013-08-15T05:59:07Z

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

tracing: Remove locking trace_types_lock from tracing_reset_all_online_cpus()

2013-08-04T08:50:44Z

commit 09d8091c024ec88d1541d93eb8ddb2bd5cf10c39 upstream. Commit a82274151af "tracing: Protect ftrace_trace_arrays list in trace_events.c" added taking the trace_types_lock mutex in trace_events.c as there were several locations that needed it for protection. Unfortunately, it also encapsulated a call to tracing_reset_all_online_cpus() which also takes the trace_types_lock, causing a deadlock. This happens when a module has tracepoints and has been traced. When the module is removed, the trace events module notifier will grab the trace_types_lock, do a bunch of clean ups, and also clears the buffer by calling tracing_reset_all_online_cpus. This doesn't happen often which explains why it wasn't caught right away. Commit a82274151af was marked for stable, which means this must be sent to stable too. Link: http://lkml.kernel.org/r/51EEC646.7070306@broadcom.com Reported-by: Arend van Spril Tested-by: Arend van Spriel Cc: Alexander Z Lam Cc: Vaibhav Nagarnaik Cc: David Sharp Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman

tracing: Kill the unbalanced tr->ref++ in tracing_buffers_open()

2013-08-04T08:50:43Z

commit e70e78e3c83b536730e31231dd9b979768d8df3c upstream. tracing_buffers_open() does trace_array_get() and then it wrongly inrcements tr->ref again under trace_types_lock. This means that every caller leaks trace_array: # cd /sys/kernel/debug/tracing/ # mkdir instances/X # true < instances/X/per_cpu/cpu0/trace_pipe_raw # rmdir instances/X rmdir: failed to remove `instances/X': Device or resource busy Link: http://lkml.kernel.org/r/20130719153644.GA18899@redhat.com Signed-off-by: Oleg Nesterov Cc: Ingo Molnar Cc: Frederic Weisbecker Cc: Masami Hiramatsu Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman

tracing: Miscellaneous fixes for trace_array ref counting

2013-08-04T08:50:42Z

commit f77d09a384676bde6445413949d9d2c508ff3e62 upstream. Some error paths did not handle ref counting properly, and some trace files need ref counting. Link: http://lkml.kernel.org/r/1374171524-11948-1-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 error handling to ensure instances can always be removed

2013-08-04T08:50:41Z

commit 609e85a70bcd0eedf4ec60639dbcfb1ab011e054 upstream. Remove debugfs directories for tracing instances during creation if an error occurs causing the trace_array for that instance to not be added to ftrace_trace_arrays. If the directory continues to exist after the error, it cannot be removed because the respective trace_array is not in ftrace_trace_arrays. Link: http://lkml.kernel.org/r/1373502874-1706-2-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: Add trace_array_get/put() to event handling

2013-07-25T21:07:43Z

commit 8e2e2fa47129532a30cff6c25a47078dc97d9260 upstream. Commit a695cb58162 "tracing: Prevent deleting instances when they are being read" tried to fix a race between deleting a trace instance and reading contents of a trace file. But it wasn't good enough. The following could crash the kernel: # cd /sys/kernel/debug/tracing/instances # ( while :; do mkdir foo; rmdir foo; done ) & # ( while :; do echo 1 > foo/events/sched/sched_switch 2> /dev/null; done ) & Luckily this can only be done by root user, but it should be fixed regardless. The problem is that a delete of the file can happen after the write to the event is opened, but before the enabling happens. The solution is to make sure the trace_array is available before succeeding in opening for write, and incerment the ref counter while opened. Now the instance can be deleted when the events are writing to the buffer, but the deletion of the instance will disable all events before the instance is actually deleted. Reported-by: Alexander Lam Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman

tracing: Fix race between deleting buffer and setting events

2013-07-25T21:07:43Z

commit 2a6c24afab70dbcfee49f4c76e1511eec1a3298b upstream. While analyzing the code, I discovered that there's a potential race between deleting a trace instance and setting events. There are a few races that can occur if events are being traced as the buffer is being deleted. Mostly the problem comes with freeing the descriptor used by the trace event callback. To prevent problems like this, the events are disabled before the buffer is deleted. The problem with the current solution is that the event_mutex is let go between disabling the events and freeing the files, which means that the events could be enabled again while the freeing takes place. Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman