Subject: [lkp-robot] [bpf] 76cdd39f41: WARNING:trinity-c0_still_has_locks_held

From: kernel test robot <[email-masked]>
Date: Thu, 26 Oct 2017 00:18:27 +0800

FYI, we noticed the following commit (built with gcc-4.8):

commit: 76cdd39f4117a6cbd520b5d09993ac87acbdcfd8 ("bpf: permit multiple bpf attachments for a single perf event")
url: https://github.com/0day-ci/linux/commits/Yonghong-Song/bpf-permit-multiple-bpf-attachments-for-a-single-perf-tracepoint-event/20171024-080608

in testcase: boot

on test machine: qemu-system-x86_64 -enable-kvm -smp 2 -m 512M

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):

+----------------+------------+------------+
|                | 052bd6a4fb | 76cdd39f41 |
+----------------+------------+------------+
| boot_successes | 64         | 66         |
+----------------+------------+------------+

[   50.247341] WARNING: trinity-c0/3371 still has locks held!
[main] Random reseed: 4199236289
[   50.258948] 4.14.0-rc5-01671-g76cdd39 #1 Not tainted
[   50.260888] ------------------------------------
[child0:3373] io_getevents (208) returned ENOSYS, marking as inactive.
[child0:3373] sysfs (139) returned ENOSYS, marking as inactive.
[   50.273066] 1 lock held by trinity-c0/3371:
[   50.274247]  #0:  (bpf_event_mutex){....}, at: [<ffffffff811cd617>] perf_event_detach_bpf_prog+0x17/0xd0
[child0:3373] fanotify_mark (301) returned ENOSYS, marking as inactive.
*** glibc detected *** /trinity: double free or corruption (out): 0x0000000001d51000 ***
[   50.288585] 
[   50.288585] stack backtrace:
[   50.290123] CPU: 1 PID: 3371 Comm: trinity-c0 Not tainted 4.14.0-rc5-01671-g76cdd39 #1
[   50.292804] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[   50.295763] Call Trace:
[   50.296791]  dump_stack+0xcb/0x13f
[   50.298244]  do_exit+0xf1f/0x1380
[   50.299525]  ? syscall_trace_enter+0x3ce/0x490
[   50.301186]  do_group_exit+0x9d/0x120
[   50.302531]  SyS_exit_group+0xb/0x10
[   50.303746]  do_syscall_64+0xa6/0x240
[   50.305256]  entry_SYSCALL64_slow_path+0x25/0x25
[   50.306847] RIP: 0033:0x7f60b8dae408
[   50.307944] RSP: 002b:00007fff020656e8 EFLAGS: 00000206 ORIG_RAX: 00000000000000e7
[   50.310457] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f60b8dae408
[   50.312482] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
[   50.314526] RBP: 00007fff020665a0 R08: 00000000000000e7 R09: ffffffffffffffa0
[   50.316981] R10: 00007fff02065480 R11: 0000000000000206 R12: 0000000000000299
[   50.319413] R13: 0000000000000059 R14: 00007fff02065d10 R15: 0000000000000002
======= Backtrace: =========

To reproduce:

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script  # job-script is attached in this email

Thanks,
Xiaolong