linux/kernel/trace
Steven Rostedt 4a0b1665db tracing: Fix irqoff selftest expanding max buffer
If the kernel command line declares a tracer "ftrace=sometracer" and
that tracer is either not defined or is enabled after irqsoff,
then the irqs off selftest will fail with the following error:

Testing tracer irqsoff:
------------[ cut here ]------------
WARNING: at /home/rostedt/work/autotest/nobackup/linux-test.git/kernel/trace/tra
ce.c:713 update_max_tr_single+0xfa/0x11b()
Hardware name:
Modules linked in:
Pid: 1, comm: swapper Not tainted 2.6.38-rc8-test #1
Call Trace:
 [<c0441d9d>] ? warn_slowpath_common+0x65/0x7a
 [<c049adb2>] ? update_max_tr_single+0xfa/0x11b
 [<c0441dc1>] ? warn_slowpath_null+0xf/0x13
 [<c049adb2>] ? update_max_tr_single+0xfa/0x11b
 [<c049e454>] ? stop_critical_timing+0x154/0x204
 [<c049b54b>] ? trace_selftest_startup_irqsoff+0x5b/0xc1
 [<c049b54b>] ? trace_selftest_startup_irqsoff+0x5b/0xc1
 [<c049b54b>] ? trace_selftest_startup_irqsoff+0x5b/0xc1
 [<c049e529>] ? time_hardirqs_on+0x25/0x28
 [<c0468bca>] ? trace_hardirqs_on_caller+0x18/0x12f
 [<c0468cec>] ? trace_hardirqs_on+0xb/0xd
 [<c049b54b>] ? trace_selftest_startup_irqsoff+0x5b/0xc1
 [<c049b6b8>] ? register_tracer+0xf8/0x1a3
 [<c14e93fe>] ? init_irqsoff_tracer+0xd/0x11
 [<c040115e>] ? do_one_initcall+0x71/0x121
 [<c14e93f1>] ? init_irqsoff_tracer+0x0/0x11
 [<c14ce3a9>] ? kernel_init+0x13a/0x1b6
 [<c14ce26f>] ? kernel_init+0x0/0x1b6
 [<c0403842>] ? kernel_thread_helper+0x6/0x10
---[ end trace e93713a9d40cd06c ]---
.. no entries found ..FAILED!

What happens is the "ftrace=..." will expand the ring buffer to its
default size (from its minimum size) but it will not expand the
max ring buffer (the ring buffer to store maximum latencies).
When the irqsoff test runs, it will call the ring buffer swap routine
that checks if the max ring buffer is the same size as the normal
ring buffer, and will fail if it is not. This causes the test to fail.

The solution is to expand the max ring buffer before running the self
test if the max ring buffer is used by that tracer and the normal ring
buffer is expanded. The max ring buffer should be shrunk again after
the test is done to save space.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-03-10 10:34:58 -05:00
..
blktrace.c blktrace: Remove blk_fill_rwbs_rq. 2011-03-03 10:53:20 -05:00
ftrace.c ftrace: Fix memory leak with function graph and cpu hotplug 2011-02-11 16:23:33 -05:00
Kconfig perf: Clean up power events by introducing new, more generic ones 2011-01-04 08:16:54 +01:00
Makefile tracing: Fix TRACE_EVENT power tracepoint creation 2011-01-07 23:26:29 -05:00
power-traces.c perf: Clean up power events by introducing new, more generic ones 2011-01-04 08:16:54 +01:00
ring_buffer_benchmark.c
ring_buffer.c tracing: Explain about unstable clock on resume with ring buffer warning 2011-03-10 10:34:47 -05:00
trace_branch.c tracing: Allow events to share their print functions 2010-05-14 14:20:32 -04:00
trace_clock.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-08-06 09:39:22 -07:00
trace_entries.h tracing: Fix event alignment: ftrace:context_switch and ftrace:wakeup 2011-03-10 10:34:16 -05:00
trace_event_perf.c tracing: New flag to allow non privileged users to use a trace event 2010-11-18 14:37:40 +01:00
trace_events_filter.c tracing/filter: Remove synchronize_sched() from __alloc_preds() 2011-02-07 20:56:20 -05:00
trace_events.c tracing: Export trace_set_clr_event() 2011-03-10 10:34:51 -05:00
trace_export.c tracing: Replace trace_event struct array with pointer array 2011-02-02 21:37:13 -05:00
trace_functions_graph.c tracing: Remove parent recording in latency tracer graph options 2010-10-18 10:53:38 -04:00
trace_functions.c tracing: Remove ftrace_preempt_disable/enable 2010-06-03 19:32:38 -04:00
trace_irqsoff.c lockdep: Move early boot local IRQ enable/disable status to init/main.c 2011-01-20 13:32:33 +01:00
trace_kdb.c kdb,ftdump: Remove reference to internal kdb include 2010-10-22 15:34:11 -05:00
trace_kprobe.c tracing/kprobe: Fix NULL pointer deref check 2011-02-14 12:09:53 +01:00
trace_mmiotrace.c
trace_nop.c
trace_output.c tracing: Adjust conditional expression latency formatting. 2011-03-10 10:34:35 -05:00
trace_output.h tracing: Allow events to share their print functions 2010-05-14 14:20:32 -04:00
trace_printk.c
trace_sched_switch.c tracing: Remove obsolete sched_switch tracer 2011-02-08 17:14:56 -05:00
trace_sched_wakeup.c tracing: Fix compile issue for trace_sched_wakeup.c 2010-10-19 10:56:19 -04:00
trace_selftest_dynamic.c
trace_selftest.c sched: Constify function scope static struct sched_param usage 2011-01-07 15:55:45 +01:00
trace_stack.c llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
trace_stat.c
trace_stat.h
trace_syscalls.c tracing/syscalls: Early terminate search for sys_ni_syscall 2011-02-07 21:30:14 -05:00
trace_workqueue.c jump label: Initialize workqueue tracepoints *before* they are registered 2010-09-22 16:30:03 -04:00
trace.c tracing: Fix irqoff selftest expanding max buffer 2011-03-10 10:34:58 -05:00
trace.h tracing: Align 4 byte ints together in struct tracer 2011-03-10 10:34:54 -05:00