kernel warning at kern/src/event.c:374, from core 3: [kernel] Null ev_q - kernel code should check before sending! Stack Backtrace on Core 3: #01 [<0xffffffffc200a38c>] in backtrace at src/kdebug.c:229 #02 [<0xffffffffc2009bb4>] in _warn at src/init.c:322 #03 [<0xffffffffc2007732>] in send_event at src/event.c:374 #04 [<0xffffffffc2056a45>] in sys_send_event at src/syscall.c:1439 #05 [<0xffffffffc205a019>] in syscall at src/syscall.c:2465 #06 [<0xffffffffc205a1f8>] in run_local_syscall at src/syscall.c:2500 #07 [<0xffffffffc205a739>] in prep_syscalls at src/syscall.c:2520 #08 [<0xffffffffc20abee2>] in sysenter_callwrapper at arch/x86/trap.c:854