perf: fuzzer lockup in perf_swevent_overflow

[Vince Weaver]

Though not sure, having trouble parsing this one.  This is on a core2
system.  Somewhat unusual in that it seems 
as though the network watchdog caught the lockup.

[19849.952009] ------------[ cut here ]------------
[19849.956645] WARNING: CPU: 0 PID: 23863 at net/sched/sch_generic.c:316 dev_watchdog+0xde/0x139
[19849.965190] NETDEV WATCHDOG: eth1 (MOSCHIP usb-ethernet driver): transmit queue 0 timed out
[19850.003825] CPU: 0 PID: 23863 Comm: perf_fuzzer Tainted: G        W       4.8.0+ #209
[19850.004272] Hardware name: AOpen   DE7000/nMCP7ALPx-DE R1.06 Oct.19.2012, BIOS 080015  10/19/2012
[19850.004272]  ffff88011fc03dc8 ffffffff812bc679 ffff88011fc03e18 0000000000000000
[19850.004272]  ffff88011fc03e08 ffffffff8104e0c8 0000013c1fc03e80 ffff8801185fa000
[19850.004272]  0000000000000100 ffffffff814c456b ffff8801185fa478 ffff8801185fa000
[19850.004272] Call Trace:
[19850.004272]  <IRQ> [19850.004272]  [<ffffffff812bc679>] dump_stack+0x4d/0x63
[19850.004272]  [<ffffffff8104e0c8>] __warn+0xca/0xe5
[19850.004272]  [<ffffffff814c456b>] ? netif_tx_lock+0x79/0x79
[19850.004272]  [<ffffffff8104e12e>] warn_slowpath_fmt+0x4b/0x53
[19850.004272]  [<ffffffff8158dbdc>] ? _raw_spin_lock+0xe/0x10
[19850.004272]  [<ffffffff814c453d>] ? netif_tx_lock+0x4b/0x79
[19850.004272]  [<ffffffff814c4649>] dev_watchdog+0xde/0x139
[19850.004272]  [<ffffffff8109ab0f>] call_timer_fn+0x62/0x121
[19850.004272]  [<ffffffff8109aff7>] __run_timers.part.36+0x17a/0x1a0
[19850.004272]  [<ffffffff8109b109>] run_timer_softirq+0x2e/0x58
[19850.004272]  [<ffffffff810529d4>] __do_softirq+0x100/0x265
[19850.004272]  [<ffffffff810a7ab6>] ? tick_program_event+0x62/0x69
[19850.004272]  [<ffffffff81052cce>] irq_exit+0x52/0x93
[19850.004272]  [<ffffffff81034c6d>] smp_trace_apic_timer_interrupt+0x8c/0xc3
[19850.004272]  [<ffffffff8158ea1f>] trace_apic_timer_interrupt+0x7f/0x90
[19850.004272]  <EOI> [19850.004272]  [<ffffffff810f9027>] ? perf_swevent_overflow+0x55/0x5b
[19850.004272]  [<ffffffff810f9098>] perf_swevent_event+0x6b/0x6d
[19850.004272]  [<ffffffff810f92a5>] perf_tp_event+0x117/0x1d2
[19850.004272]  [<ffffffff81017808>] ? do_signal+0x5b4/0x670
[19850.004272]  [<ffffffff810f93db>] perf_trace_run_bpf_submit+0x7b/0x8c
[19850.004272]  [<ffffffff810f93db>] ? perf_trace_run_bpf_submit+0x7b/0x8c
[19850.004272]  [<ffffffff81057ba7>] ? recalc_sigpending_tsk+0x42/0x49
[19850.004272]  [<ffffffff8100136d>] perf_trace_sys_exit+0xb1/0xc0
[19850.004272]  [<ffffffff810016a1>] syscall_return_slowpath+0x9d/0xa7
[19850.004272]  [<ffffffff8100170f>] do_syscall_64+0x64/0x67
[19850.004272]  [<ffffffff8158de4a>] entry_SYSCALL64_slow_path+0x25/0x25
[19850.200778] ---[ end trace 663224088a604af2 ]---