WARNING: CPU: 0 PID: 8768 at kernel/fork.c:718 __put_task_struct+0x3ef/0x620 kernel/fork.c:718
kobject: 'loop0' (00000000ac64c87e): kobject_uevent_env
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 8768 Comm: syz-executor4 Not tainted 4.19.0-rc7-next-20181010+ #91
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
kobject: 'loop0' (00000000ac64c87e): fill_kobj_path: path = '/devices/virtual/block/loop0'
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x244/0x3ab lib/dump_stack.c:113
 panic+0x238/0x4e7 kernel/panic.c:184
 __warn.cold.8+0x163/0x1ba kernel/panic.c:536
 report_bug+0x254/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969
RIP: 0010:__put_task_struct+0x3ef/0x620 kernel/fork.c:718
Code: 4c 89 ee e8 13 a2 7b 00 e9 a1 fe ff ff e8 69 55 37 00 0f 0b e9 7c fd ff ff e8 5d 55 37 00 0f 0b e9 87 fd ff ff e8 51 55 37 00 <0f> 0b e9 d0 fc ff ff e8 45 55 37 00 49 8d 87 90 05 00 00 31 f6 48
RSP: 0018:ffff880191cef808 EFLAGS: 00010293
RAX: ffff880189eae200 RBX: ffff8801cf114200 RCX: ffffffff814711cd
RDX: 0000000000000000 RSI: ffffffff814714ff RDI: 0000000000000005
RBP: ffff880191cef8e8 R08: ffff880189eae200 R09: ffffed0039e22844
R10: ffffed0039e22844 R11: ffff8801cf114223 R12: 1ffff1003239df04
R13: 0000000000000000 R14: ffff880191cef8c0 R15: ffff88018ad6f240
 put_task_struct include/linux/sched/task.h:96 [inline]
 rdma_restrack_del+0x2e0/0x3b0 drivers/infiniband/core/restrack.c:243
 rdma_destroy_id+0x126/0xcc0 drivers/infiniband/core/cma.c:1820
 ucma_close+0x114/0x310 drivers/infiniband/core/ucma.c:1767
 __fput+0x3bc/0xa70 fs/file_table.c:279
 ____fput+0x15/0x20 fs/file_table.c:312
 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x411051
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 34 19 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffd4e937920 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000009 RCX: 0000000000411051
RDX: 0000000000000000 RSI: 0000000000732c78 RDI: 0000000000000008
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffd4e937850 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000000024 R15: 0000000000000004
Kernel Offset: disabled
Rebooting in 86400 seconds..