Unknown Exception : signal SIGPIPE with crash when device is unlocked after locked screen

I have serious problem for this in my ios app. I can't understand what is this and how to solve this. I also don't know by which code this crash occurred so i can't provide code here right now. My app crashed if i unlocked device from locked situation. It shows following report.

libsystem_kernel.dylib`mach_msg_trap:
0x34842504:  mov    r12, sp
0x34842508:  push   {r4, r5, r6, r8}
0x3484250c:  ldm    r12, {r4, r5, r6}
0x34842510:  mvn    r12, #0x1e
0x34842514:  svc    #0x80
0x34842518:  pop    {r4, r5, r6, r8}               //Thread 1: signal SIGPIPE
0x3484251c:  bx     lr

This is shown when i unlock the screen

I have no idea about this. My app is compatible for ios 7 and above. Any help will be appreciated. Thanks.

Solution

I have found solution of this problem. It is signal which cause in debugger only. If I debug the code with device then it cause this and pause the app and if I resume then app is working perfectly. Then I have checked this by removing device and run the app without debugging then there is no any pause and app is working perfectly as it is normal. It is issue of just hit play/resume in the debugger.