Re: 3.18-rc2 perf add_event_to_ctx warning

[Dave Jones <davej@redhat.com>]

On Thu, Oct 30, 2014 at 07:40:29PM -0400, Dave Jones wrote:
 > WARNING: CPU: 3 PID: 5167 at kernel/events/core.c:1133 add_event_to_ctx+0x1ce/0x1f0()
 > CPU: 3 PID: 5167 Comm: trinity-c4 Not tainted 3.18.0-rc2+ #79
 >  0000000000000009 0000000071bbcfa0 ffff880235ef3c48 ffffffffbd86ef44
 >  0000000000000000 0000000000000000 ffff880235ef3c88 ffffffffbd07f1f1
 >  ffff880235ef3c78 ffff880233e6eee8 ffff880089e4c0f8 0000000001a2978c
 > Call Trace:
 >  [<ffffffffbd86ef44>] dump_stack+0x4f/0x7c
 >  [<ffffffffbd07f1f1>] warn_slowpath_common+0x81/0xa0
 >  [<ffffffffbd07f30a>] warn_slowpath_null+0x1a/0x20
 >  [<ffffffffbd19a68e>] add_event_to_ctx+0x1ce/0x1f0
 >  [<ffffffffbd1a03a3>] __perf_install_in_context+0xe3/0x1b0
 >  [<ffffffffbd19a0a3>] remote_function+0x53/0x70
 >  [<ffffffffbd19a050>] ? schedule_orphans_remove.part.49+0x60/0x60
 >  [<ffffffffbd1247b6>] generic_exec_single+0x156/0x1d0
 >  [<ffffffffbd19a050>] ? schedule_orphans_remove.part.49+0x60/0x60
 >  [<ffffffffbd124896>] smp_call_function_single+0x66/0x110
 >  [<ffffffffbd0f460e>] ? wait_rcu_gp+0x8e/0xb0
 >  [<ffffffffbd198f93>] task_function_call+0x53/0x80
 >  [<ffffffffbd1a02c0>] ? perf_cpu_hrtimer_handler+0x260/0x260
 >  [<ffffffffbd19a733>] perf_install_in_context+0x83/0xf0
 >  [<ffffffffbd1a4d80>] SYSC_perf_event_open+0xb70/0xc70
 >  [<ffffffffbd3ebf27>] ? debug_smp_processor_id+0x17/0x20
 >  [<ffffffffbd1a52c9>] SyS_perf_event_open+0x9/0x10
 >  [<ffffffffbd87a009>] tracesys_phase2+0xd4/0xd9
 > ---[ end trace 88ffecbb23768dcb ]---
 > 
 > 
 > 1133         WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);

Still seeing this (unsurprising, as perf hasn't changed any
between rc2 & rc5).  Any thoughts on this one ?
I've not managed to isolate a testcase for it, but I see it every
week or so.

	Dave