Replay failed with "Expected syscall_bp_vm to be clear"

In trace julia-9 from https://buildkite.com/organizations/julialang/pipelines/julia-master/builds/13170/jobs/01819131-f9a7-48e4-926f-23e48419c663/artifacts/018191c4-b7b8-461b-97c8-6f6f44bfc49f, we have when attempting to replay:

[FATAL src/ReplaySession.cc:632:enter_syscall()]
 (task 14658 (rec:1978) at time 2968298)
 -> Assertion `false' failed to hold. Expected syscall_bp_vm to be clear but it's 1978's address space with a breakpoint at 0x7ff02dca8744 while we're at 0x70000002
Tail of trace dump:

[snip]

  real_time:52858533.422724 global_time:2968294, event:`SYSCALL: epoll_wait' (state:EXITING_SYSCALL) tid:579, ticks:415456293513
rax:0x1 rbx:0x681fffa0 rcx:0xffffffffffffffff rdx:0x400 rsi:0x7f50b86166c0 rdi:0x5 rbp:0x0 rsp:0x681ffde0 r8:0x0 r9:0x7f50ccc3fca0 r10:0xbb9 r11:0x246 r12:0xbb9 r13:0x7f50d858006e r14:0x7f50b86166c0 r15:0x7f50d858306e rip:0x70000002 eflags:0x246 cs:0x33 ss:0x2b ds:0x0 es:0x0 fs:0x0 gs:0x0 orig_rax:0xe8 fs_base:0x7f50df703180 gs_base:0x0
  { tid:579, addr:0x7f50b86166c0, length:0x3000 }
}
{
  real_time:52858533.423096 global_time:2968295, event:`SYSCALLBUF_FLUSH' tid:579, ticks:415456303524
  { syscall:'clock_gettime', ret:0x0, size:0x20 }
  { syscall:'read', ret:0xfff, size:0x100f, desched:1 }
  { syscall:'clock_gettime', ret:0x0, size:0x20 }
  { syscall:'clock_gettime', ret:0x0, size:0x20 }
  { syscall:'epoll_wait', ret:0x1, size:0x1c }
  { syscall:'clock_gettime', ret:0x0, size:0x20 }
  { syscall:'read', ret:0x6e4, size:0x6f4, desched:1 }
  { syscall:'clock_gettime', ret:0x0, size:0x20 }
  { syscall:'epoll_wait', ret:0x0, size:0x10 }
}
{
  real_time:52858533.423110 global_time:2968296, event:`SYSCALL: epoll_wait' (state:ENTERING_SYSCALL) tid:579, ticks:415456303524
rax:0xffffffffffffffda rbx:0x681fffa0 rcx:0xffffffffffffffff rdx:0x400 rsi:0x7f50bcb6de60 rdi:0x5 rbp:0x0 rsp:0x681ffde0 r8:0x0 r9:0x7f50ccc3fca0 r10:0xa36 r11:0x246 r12:0xa36 r13:0x7f50d85817f6 r14:0x7f50bcb6de60 r15:0x7f50d85847f6 rip:0x70000002 eflags:0x246 cs:0x33 ss:0x2b ds:0x0 es:0x0 fs:0x0 gs:0x0 orig_rax:0xe8 fs_base:0x7f50df703180 gs_base:0x0
}
{
  real_time:52858533.423128 global_time:2968297, event:`SYSCALLBUF_RESET' tid:579, ticks:415456303524
}
{
  real_time:52858533.423177 global_time:2968298, event:`SYSCALL: exit_group' (state:ENTERING_SYSCALL) tid:1978, ticks:372899180
rax:0xffffffffffffffda rbx:0x7ff02dd98760 rcx:0xffffffffffffffff rdx:0x8f rsi:0x3c rdi:0x8f rbp:0x8f rsp:0x7ff02157ef68 r8:0xe7 r9:0xffffffffffffff78 r10:0xfffffffffffff81f r11:0x246 r12:0x7ff02dd98760 r13:0x63d r14:0x7ff02dda1428 r15:0x0 rip:0x7ff02dca8746 eflags:0x246 cs:0x33 ss:0x2b ds:0x0 es:0x0 fs:0x0 gs:0x0 orig_rax:0xe7 fs_base:0x7ff02dbbf180 gs_base:0x0
}
{
  real_time:52858533.423188 global_time:2968299, event:`EXIT' tid:1978, ticks:372899180
}

Will look into this further.

Start in src/ReplaySession.cc at enter_syscall(), line 632, and reproduce the replay failure using the linked julia-9 trace artifact. Inspect how syscall_bp_vm and the breakpoint at 0x7ff02dca8744 are handled around the recorded exit_group and epoll_wait events. Done means determining why the assertion occurs and making replay handle this trace without the fatal failure.