Comment 11 for bug 1746225

------- Comment From <email address hidden> 2018-02-27 00:25 EDT-------
Hi ,
Unable to hit the above call trace , hence the issue is resolved.

Verified on kernel :

root@ltc-wcwsp1:~/shriya/kernel# uname -a
Linux ltc-wcwsp1 4.15.0-10-generic #11 SMP Fri Feb 23 01:59:38 EST 2018 ppc64le ppc64le ppc64le GNU/Linux

Perf fuzzer :
=======
+ ./perf_fuzzer -r 1492143527
Using user-specified random seed of 1492143527

*** perf_fuzzer 0.32-rc0 *** by Vince Weaver

Linux version 4.15.0-10-generic ppc64le
Processor: ppc64le UNKNOWN

Watchdog enabled with timeout 60s
Will auto-exit if signal storm detected
Seeding RNG with supplied seed 1492143527

To reproduce, try:
echo 0 > /proc/sys/kernel/nmi_watchdog
echo 2 > /proc/sys/kernel/perf_event_paranoid
echo 100000 > /proc/sys/kernel/perf_event_max_sample_rate
./perf_fuzzer -r 1492143527

Fuzzing the following syscalls: mmap perf_event_open close read write ioctl fork prctl poll
Also attempting the following: signal-handler-on-overflow busy-instruction-loop accessing-perf-proc-and-sys-files trashing-the-mmap-page

Pid=4506, sleeping 1s

==================================================
Starting fuzzing at 2018-02-26 21:36:45
==================================================
Cannot open /sys/kernel/tracing/kprobe_events
Iteration 10000, 98728 syscalls in 5.32 s (18.554 k syscalls/s)
Open attempts: 90726 Successful: 917 Currently open: 54
ENOENT : 446
E2BIG : 7816
EBADF : 8522
EINVAL : 72718
ENOSPC : 81
EOVERFLOW : 2
EOPNOTSUPP : 224
Trinity Type (Normal 345/22780)(Sampling 28/22630)(Global 488/22586)(Random 56/22730)
Type (Hardware 246/12690)(software 362/11897)(tracepoint 58/11874)(Cache 55/11258)(cpu 136/11638)(breakpoint 33/11690)(nest_capp0_imc 1/357)(nest_capp1_imc 1/365)(core_imc 0/460)(nest_mba0_imc 1/378)(nest_mba1_imc 0/352)(nest_mba2_imc 0/362)(nest_mba3_imc 1/371)(nest_mba4_imc 1/357)(nest_mba5_imc 0/320)(nest_mba6_imc 1/358)(nest_mba7_imc 0/439)(nest_mcs01_imc 0/359)(nest_mcs23_imc 2/361)(nest_nvlink0_imc 19/14840)
Close: 863/863 Successful
Read: 824/912 Successful
Write: 0/855 Successful
Ioctl: 371/924 Successful: (ENABLE 91/91)(DISABLE 81/81)(REFRESH 9/78)(RESET 84/84)(PERIOD 2/75)(SET_OUTPUT 8/80)(SET_FILTER 0/92)(ID 87/87)(SET_BPF 0/91)(PAUSE_OUTPUT 9/79)(#10 0/0)(#11 0/0)(#12 0/0)(#13 0/0)(#14 0/0)(>14 0/86)
Mmap: 662/1060 Successful: (MMAP 662/1060)(TRASH 144/156)(READ 133/143)(UNMAP 653/988)(AUX 0/169)(AUX_READ 0/0)
Prctl: 929/929 Successful
Fork: 471/471 Successful
Poll: 895/921 Successful
Access: 0/0 Successful
Overflows: 0 Recursive: 0
SIGIOs due to RT signal queue full: 0
Memset of mmap#18 at (nil) caused segfault!
MAP_SHARED MAP_DENYWRITE MAP_FIXED MAP_NONBLOCK MAP_STACK PROT_READ PROT_WRITE size 27661 fd 47
event: cpu=4 pid=-1 group_fd=-1 flags=9
memset(&pe[47],0,sizeof(struct perf_event_attr));
pe[47].type=PERF_TYPE_SOFTWARE;
pe[47].size=64;
pe[47].config=PERF_COUNT_SW_PAGE_FAULTS;
pe[47].sample_type=0; /* 0 */
pe[47].read_format=PERF_FORMAT_TOTAL_TIME_RUNNING|PERF_FORMAT_GROUP; /* a */
pe[47].disabled=1;
pe[47].inherit=1;
pe[47].pinned=1;
pe[47].precise_ip=0; /* arbitrary skid */
pe[47].wakeup_events=0;
pe[47].bp_type=HW_BREAKPOINT_EMPTY;