Re: perf: perf_fuzzer quickly locks up on 4.15-rc7

[Vince Weaver]

on the same core2 machine I got this which didn't crash the machine (but 
the perf_fuzzer process is stuck)

[ 4592.608066] INFO: task systemd-logind:488 blocked for more than 120 seconds.
[ 4592.615159]       Not tainted 4.15.0-rc7+ #211
[ 4592.619648] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 4592.627512] systemd-logind  D    0   488      1 0x80000006
[ 4592.633039] Call Trace:
[ 4592.635529]  ? __schedule+0x35d/0x507
[ 4592.639239]  ? usleep_range+0x51/0x51
[ 4592.642948]  ? schedule+0x7b/0x84
[ 4592.646310]  ? schedule_timeout+0x21/0xc7
[ 4592.650368]  ? ttwu_do_wakeup+0x19/0x10d
[ 4592.654339]  ? do_wait_for_common+0xfe/0x12f
[ 4592.658653]  ? wake_up_q+0x40/0x40
[ 4592.662106]  ? wait_for_common+0x35/0x3f
[ 4592.666075]  ? __wait_rcu_gp+0xe9/0xfa
[ 4592.669872]  ? synchronize_sched+0x3e/0x43
[ 4592.674019]  ? call_rcu_bh+0x13/0x13
[ 4592.677641]  ? trace_raw_output_rcu_utilization+0x42/0x42
[ 4592.683086]  ? evdev_release+0x81/0xcf [evdev]
[ 4592.687578]  ? __fput+0xdf/0x18f
[ 4592.690852]  ? task_work_run+0x6b/0x7f
[ 4592.694650]  ? do_exit+0x4b1/0x994
[ 4592.698103]  ? __perf_event_task_sched_out+0x62/0x302
[ 4592.703200]  ? do_group_exit+0x3b/0xa9
[ 4592.707000]  ? get_signal+0x490/0x50b
[ 4592.710714]  ? do_signal+0x23/0x5ea
[ 4592.714249]  ? schedule_hrtimeout_range_clock+0x38/0xcf
[ 4592.719521]  ? ep_scan_ready_list+0x176/0x195
[ 4592.723926]  ? SYSC_epoll_wait+0x2ea/0x39d
[ 4592.728074]  ? prepare_exit_to_usermode+0xd1/0x102
[ 4592.732913]  ? entry_SYSCALL_64_fastpath+0x6e/0x70
[ 4601.468052] INFO: rcu_sched detected stalls on CPUs/tasks:
[ 4601.473590]  1-...0: (1 GPs behind) idle=74e/140000000000000/0 softirq=139228/139229 fqs=28744 
[ 4601.482338]  (detected by 0, t=60007 jiffies, g=67462, c=67461, q=1637)
[ 4601.488996] Sending NMI from CPU 0 to CPUs 1: