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remarkable-linux/kernel/trace
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Steven Rostedt b9ef0326c0 tracing: Move postpone selftests to core from early_initcall 
I hit the following lockdep splat when booting with ftrace selftests
enabled, as well as CONFIG_PREEMPT and LOCKDEP.

 Testing dynamic ftrace ops #1:
 (1 0 1 0 0)
 (1 1 2 0 0)
 (2 1 3 0 169)
 (2 2 4 0 50066)
 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 13 at kernel/rcu/srcutree.c:202 check_init_srcu_struct+0x60/0x70
 Modules linked in:
 CPU: 0 PID: 13 Comm: rcu_tasks_kthre Not tainted 4.12.0-rc1-test+ #587
 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012
 task: ffff880119628040 task.stack: ffffc900006a4000
 RIP: 0010:check_init_srcu_struct+0x60/0x70
 RSP: 0000:ffffc900006a7d98 EFLAGS: 00010246
 RAX: 0000000000000246 RBX: 0000000000000000 RCX: 0000000000000000
 RDX: ffff880119628040 RSI: 00000000ffffffff RDI: ffffffff81e5fb40
 RBP: ffffc900006a7e20 R08: 00000023b403c000 R09: 0000000000000001
 R10: ffffc900006a7e40 R11: 0000000000000000 R12: ffffffff81e5fb40
 R13: 0000000000000286 R14: ffff880119628040 R15: ffffc900006a7e98
 FS:  0000000000000000(0000) GS:ffff88011ea00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: ffff88011edff000 CR3: 0000000001e0f000 CR4: 00000000001406f0
 Call Trace:
  ? __synchronize_srcu+0x6e/0x140
  ? lock_acquire+0xdc/0x1d0
  ? ktime_get_mono_fast_ns+0x5d/0xb0
  synchronize_srcu+0x6f/0x110
  ? synchronize_srcu+0x6f/0x110
  rcu_tasks_kthread+0x20a/0x540
  kthread+0x114/0x150
  ? __rcu_read_unlock+0x70/0x70
  ? kthread_create_on_node+0x40/0x40
  ret_from_fork+0x2e/0x40
 Code: f6 83 70 06 00 00 03 49 89 c5 74 0d be 01 00 00 00 48 89 df e8 42 fa ff ff 4c 89 ee 4c 89 e7 e8 b7 42 75 00 5b 41 5c 41 5d 5d c3 <0f> ff eb aa 66 90 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00
 ---[ end trace 5c3f4206ce50f6ac ]---

What happens is that the selftests include a creating of a dynamically
allocated ftrace_ops, which requires the use of synchronize_rcu_tasks()
which uses srcu, and triggers the above warning.

It appears that synchronize_rcu_tasks() is not set up at early_initcall(),
but it is at core_initcall(). By moving the tests down to that location
works out properly.

Link: http://lkml.kernel.org/r/20170517111435.7388c033@gandalf.local.home

Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2017-05-17 21:39:38 -04:00
..
blktrace.c block: remove the errors field from struct request 2017-04-20 12:16:10 -06:00
bpf_trace.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-05-02 16:40:27 -07:00
ftrace.c ftrace: Simplify ftrace_match_record() even more 2017-05-03 22:15:13 -04:00
Kconfig New features for this release: 2017-05-03 18:41:21 -07:00
Makefile perf/core: Rename CONFIG_[UK]PROBE_EVENT to CONFIG_[UK]PROBE_EVENTS 2017-03-01 10:26:39 +01:00
power-traces.c
ring_buffer.c New features for this release: 2017-05-03 18:41:21 -07:00
ring_buffer_benchmark.c ring-buffer: Return reader page back into existing ring buffer 2017-05-01 10:26:40 -04:00
rpm-traces.c
trace.c tracing: Move postpone selftests to core from early_initcall 2017-05-17 21:39:38 -04:00
trace.h New features for this release: 2017-05-03 18:41:21 -07:00
trace_benchmark.c tracing: Have the trace_event benchmark thread call cond_resched_rcu_qs() 2017-04-17 15:21:19 -04:00
trace_benchmark.h
trace_branch.c
trace_clock.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/clock.h> 2017-03-02 08:42:27 +01:00
trace_entries.h trace: make trace_hwlat timestamp y2038 safe 2017-05-08 17:15:15 -07:00
trace_event_perf.c
trace_events.c tracing/ftrace: Add a better way to pass data via the probe functions 2017-04-20 22:06:46 -04:00
trace_events_filter.c
trace_events_filter_test.h
trace_events_hist.c sched/headers: Prepare to use <linux/rcuupdate.h> instead of <linux/rculist.h> in <linux/sched.h> 2017-03-02 08:42:38 +01:00
trace_events_trigger.c sched/headers: Prepare to use <linux/rcuupdate.h> instead of <linux/rculist.h> in <linux/sched.h> 2017-03-02 08:42:38 +01:00
trace_export.c
trace_functions.c tracing/ftrace: Allow for instances to trigger their own stacktrace probes 2017-04-20 22:06:49 -04:00
trace_functions_graph.c
trace_hwlat.c trace: make trace_hwlat timestamp y2038 safe 2017-05-08 17:15:15 -07:00
trace_irqsoff.c
trace_kdb.c
trace_kprobe.c New features for this release: 2017-05-03 18:41:21 -07:00
trace_mmiotrace.c
trace_nop.c
trace_output.c trace: make trace_hwlat timestamp y2038 safe 2017-05-08 17:15:15 -07:00
trace_output.h
trace_printk.c
trace_probe.c
trace_probe.h perf/core: Rename CONFIG_[UK]PROBE_EVENT to CONFIG_[UK]PROBE_EVENTS 2017-03-01 10:26:39 +01:00
trace_sched_switch.c
trace_sched_wakeup.c
trace_selftest.c sched/headers: Prepare for new header dependencies before moving code to <uapi/linux/sched/types.h> 2017-03-02 08:42:27 +01:00
trace_selftest_dynamic.c
trace_seq.c
trace_stack.c rcu/tracing: Add rcu_disabled to denote when rcu_irq_enter() will not work 2017-04-10 15:22:03 -04:00
trace_stat.c
trace_stat.h
trace_syscalls.c
trace_uprobe.c sched/headers: Prepare to use <linux/rcuupdate.h> instead of <linux/rculist.h> in <linux/sched.h> 2017-03-02 08:42:38 +01:00
tracing_map.c
tracing_map.h