linux/kernel/trace
Linus Torvalds fc335c1b68 This contains a fix for two long standing bugs. Both of which are
rarely ever hit, and requires the user to do something that users rarely
 do. It took a few special test cases to even trigger this bug,
 and one of them was just one test in the process of finishing up as another
 one started.
 
 Both bugs have to do with the ring buffer iterator rb_iter_peek(), but one
 is more indirect than the other.
 
 The fist bug fix is simply an increase in the safety net loop counter.
 The counter makes sure that the rb_iter_peek() only iterates the number
 of times we expect it can, and no more. Well, there was one way it could
 iterate one more than we expected, and that caused the ring buffer
 to shutdown with a nasty warning. The fix was simply to up that counter by
 one.
 
 The other bug has to be with rb_iter_reset() (called by rb_iter_peek()).
 This happens when a user reads both the trace_pipe and trace files.
 The trace_pipe is a consuming read and does not use the ring buffer
 iterator, but the trace file is not a consuming read and does use the
 ring buffer iterator. When the trace file is being read, if it detects
 that a consuming read occurred, it resets the iterator and starts over.
 But the reset code that does this (rb_iter_reset()), checks if the
 reader_page is linked to the ring buffer or not, and will look into
 the ring buffer itself if it is not. This is wrong, as it should always
 try to read the reader page first. Not to mention, the code that looked
 into the ring buffer did it wrong, and used the header_page "read" offset
 to start reading on that page. That offset is bogus for pages in the
 writable ring buffer, and was corrupting the iterator, and it would start
 returning bogus events.
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Merge tag 'trace-fixes-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull trace file read iterator fixes from Steven Rostedt:
 "This contains a fix for two long standing bugs.  Both of which are
  rarely ever hit, and requires the user to do something that users
  rarely do.  It took a few special test cases to even trigger this bug,
  and one of them was just one test in the process of finishing up as
  another one started.

  Both bugs have to do with the ring buffer iterator rb_iter_peek(), but
  one is more indirect than the other.

  The fist bug fix is simply an increase in the safety net loop counter.
  The counter makes sure that the rb_iter_peek() only iterates the
  number of times we expect it can, and no more.  Well, there was one
  way it could iterate one more than we expected, and that caused the
  ring buffer to shutdown with a nasty warning.  The fix was simply to
  up that counter by one.

  The other bug has to be with rb_iter_reset() (called by
  rb_iter_peek()).  This happens when a user reads both the trace_pipe
  and trace files.  The trace_pipe is a consuming read and does not use
  the ring buffer iterator, but the trace file is not a consuming read
  and does use the ring buffer iterator.  When the trace file is being
  read, if it detects that a consuming read occurred, it resets the
  iterator and starts over.  But the reset code that does this
  (rb_iter_reset()), checks if the reader_page is linked to the ring
  buffer or not, and will look into the ring buffer itself if it is not.
  This is wrong, as it should always try to read the reader page first.
  Not to mention, the code that looked into the ring buffer did it
  wrong, and used the header_page "read" offset to start reading on that
  page.  That offset is bogus for pages in the writable ring buffer, and
  was corrupting the iterator, and it would start returning bogus
  events"

* tag 'trace-fixes-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ring-buffer: Always reset iterator to reader page
  ring-buffer: Up rb_iter_peek() loop count to 3
2014-08-09 17:29:36 -07:00
..
Kconfig tracing: Remove function_trace_stop and HAVE_FUNCTION_TRACE_MCOUNT_TEST 2014-07-18 13:58:12 -04:00
Makefile tracing: Move the trace_seq_* functions into its own trace_seq.c file 2014-07-01 07:13:35 -04:00
blktrace.c Most of the changes were largely clean ups, and some documentation. 2014-04-03 10:26:31 -07:00
ftrace.c This pull request has a lot of work done. The main thing is the changes 2014-08-04 11:50:00 -07:00
power-traces.c PM / tracing: remove deprecated power trace API 2013-01-26 00:39:12 +01:00
ring_buffer.c This contains a fix for two long standing bugs. Both of which are 2014-08-09 17:29:36 -07:00
ring_buffer_benchmark.c trace: Replace hardcoding of 19 with MAX_NICE 2014-02-27 12:41:03 +01:00
rpm-traces.c PM / Runtime: Introduce trace points for tracing rpm_* functions 2011-09-27 22:53:27 +02:00
trace.c Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-08-05 17:46:42 -07:00
trace.h tracing: let user specify tracing_thresh after selecting function_graph 2014-07-18 15:48:52 -04:00
trace_benchmark.c tracing: Only calculate stats of tracepoint benchmarks for 2^32 times 2014-06-06 00:41:38 -04:00
trace_benchmark.h tracing: Add tracepoint benchmark tracepoint 2014-05-29 22:49:54 -04:00
trace_branch.c tracing: Update event filters for multibuffer 2013-11-05 16:50:20 -05:00
trace_clock.c tracing: Fix wraparound problems in "uptime" trace clock 2014-07-21 09:56:12 -04:00
trace_entries.h tracing: Add trace_puts() for even faster trace_printk() tracing 2013-03-15 00:35:55 -04:00
trace_event_perf.c perf: Check permission only for parent tracepoint event 2014-07-28 10:01:38 +02:00
trace_events.c Oleg Nesterov did several clean ups with the tracing filter code. 2014-08-04 12:02:48 -07:00
trace_events_filter.c tracing: Kill "filter_string" arg of replace_preds() 2014-07-16 14:58:53 -04:00
trace_events_filter_test.h tracing/filter: Add startup tests for events filter 2011-08-19 14:35:59 -04:00
trace_events_trigger.c tracing: Use rcu_dereference_sched() for trace event triggers 2014-05-02 23:12:42 -04:00
trace_export.c tracing: Fix anonymous unions in struct ftrace_event_call 2014-04-09 20:02:55 -04:00
trace_functions.c tracing: Remove mock up poll wait function 2014-04-30 08:40:05 -04:00
trace_functions_graph.c tracing: Convert local function_graph functions to static 2014-07-18 21:16:06 -04:00
trace_irqsoff.c tracing: Allow irq/preempt tracers to be used by instances 2014-04-21 13:59:29 -04:00
trace_kdb.c tracing: Consolidate max_tr into main trace_array structure 2013-03-15 00:35:40 -04:00
trace_kprobe.c Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-06-12 19:18:49 -07:00
trace_mmiotrace.c tracing: Update event filters for multibuffer 2013-11-05 16:50:20 -05:00
trace_nop.c tracing: Remove mock up poll wait function 2014-04-30 08:40:05 -04:00
trace_output.c tracing: Add trace_seq_buffer_ptr() helper function 2014-07-01 07:13:39 -04:00
trace_output.h tracing: Make trace_seq_putmem_hex() more robust 2014-07-01 07:13:37 -04:00
trace_printk.c tracing: Add __tracepoint_string() to export string pointers 2013-07-26 13:39:44 -04:00
trace_probe.c kprobes, ftrace: Use NOKPROBE_SYMBOL macro in ftrace 2014-04-24 10:26:39 +02:00
trace_probe.h kprobes, ftrace: Use NOKPROBE_SYMBOL macro in ftrace 2014-04-24 10:26:39 +02:00
trace_sched_switch.c tracing: Update event filters for multibuffer 2013-11-05 16:50:20 -05:00
trace_sched_wakeup.c tracing: Remove mock up poll wait function 2014-04-30 08:40:05 -04:00
trace_selftest.c tracing: Add static to local functions 2014-04-21 14:00:46 -04:00
trace_selftest_dynamic.c ftrace: Add self-tests for multiple function trace users 2011-05-18 19:24:51 -04:00
trace_seq.c tracing: Remove trace_seq_reserve() 2014-07-01 07:13:37 -04:00
trace_stack.c tracing: Print max callstack on stacktrace bug 2014-06-02 16:43:49 -04:00
trace_stat.c trace/trace_stat: use rbtree postorder iteration helper instead of opencoding 2013-11-05 16:01:47 -05:00
trace_stat.h tracing/stat: Add stat_release() callback 2009-07-10 12:14:05 +02:00
trace_syscalls.c tracing: Consolidate event trigger code 2014-01-09 21:20:07 -05:00
trace_uprobe.c tracing/uprobes: Kill the dead TRACE_EVENT_FL_USE_CALL_FILTER logic 2014-07-16 14:25:19 -04:00