__lll_lock_wait_private () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:95 
95  in ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S 
(gdb) where 
#0  __lll_lock_wait_private () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:95 
#1  0x00007ffff705395a in _L_lock_12779 () at malloc.c:5206 
#2  0x00007ffff7051335 in __GI___libc_malloc (bytes=272) at malloc.c:2887 
#3  0x00007ffff7b1c3c2 in SDL_AddEvent (event=0x7fffffffd130) at /build/buildd/libsdl2-2.0.2+dfsg1/src/events/SDL_events.c:205 
#4  SDL_PeepEvents_REAL (events=<optimized out>, numevents=<optimized out>, action=<optimized out>, minType=0, maxType=<optimized out>) at /build/buildd/libsdl2-2.0.2+dfsg1/src/events/SDL_events.c:283 
#5  0x00007ffff7b1c6a6 in SDL_PushEvent_REAL (event=event@entry=0x7fffffffd130) at /build/buildd/libsdl2-2.0.2+dfsg1/src/events/SDL_events.c:471 
#6  0x00007ffff7b1ca3b in SDL_SendAppEvent (eventType=SDL_QUIT) at /build/buildd/libsdl2-2.0.2+dfsg1/src/events/SDL_events.c:629 
#7  <signal handler called> 
#8  malloc_consolidate (av=av@entry=0x7ffff738d760 <main_arena>) at malloc.c:4143 
#9  0x00007ffff704e0fd in _int_free (av=0x7ffff738d760 <main_arena>, p=<optimized out>, have_lock=0) at malloc.c:4057