strace: Process 1172 attached
restart_syscall(<... resuming interrupted poll ...>) = 1
fcntl(107, F_GETFL)                     = 0x2 (flags O_RDWR)
fcntl(107, F_SETFL, O_RDWR|O_NONBLOCK)  = 0
accept4(107, {sa_family=AF_INET, sin_port=htons(33496), sin_addr=inet_addr("127.0.0.1")}, [128->16], SOCK_CLOEXEC) = 159
fcntl(107, F_SETFL, O_RDWR)             = 0
fcntl(159, F_SETFD, FD_CLOEXEC)         = 0
futex(0x55efc6e555ac, FUTEX_WAKE_PRIVATE, 1) = 1
poll([{fd=107, events=POLLIN}, {fd=108, events=POLLIN}], 2, -1) = 1 ([{fd=108, revents=POLLIN}])
fcntl(108, F_GETFL)                     = 0x2 (flags O_RDWR)
fcntl(108, F_SETFL, O_RDWR|O_NONBLOCK)  = 0
accept4(108, {sa_family=AF_UNIX}, [128->2], SOCK_CLOEXEC) = 173
fcntl(108, F_SETFL, O_RDWR)             = 0
fcntl(173, F_SETFD, FD_CLOEXEC)         = 0
mmap(NULL, 307200, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_STACK, -1, 0) = 0x7f34ac718000
mprotect(0x7f34ac719000, 303104, PROT_READ|PROT_WRITE) = 0
clone(child_stack=0x7f34ac761fb0, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID, parent_tidptr=0x7f34ac7629d0, tls=0x7f34ac762700, child_tidptr=0x7f34ac7629d0) = 6928
poll([{fd=107, events=POLLIN}, {fd=108, events=POLLIN}], 2, -1) = 1 ([{fd=108, revents=POLLIN}])
fcntl(108, F_GETFL)                     = 0x2 (flags O_RDWR)
fcntl(108, F_SETFL, O_RDWR|O_NONBLOCK)  = 0
accept4(108, {sa_family=AF_UNIX}, [128->2], SOCK_CLOEXEC) = 173
fcntl(108, F_SETFL, O_RDWR)             = 0
fcntl(173, F_SETFD, FD_CLOEXEC)         = 0
futex(0x55efc6e555a8, FUTEX_WAKE_PRIVATE, 1) = 1
futex(0x55efc6e52d80, FUTEX_WAKE_PRIVATE, 1) = 1
poll([{fd=107, events=POLLIN}, {fd=108, events=POLLIN}], 2, -1) = ? ERESTART_RESTARTBLOCK (Interrupted by signal)
--- SIGUSR1 {si_signo=SIGUSR1, si_code=SI_TKILL, si_pid=1172, si_uid=997} ---
rt_sigreturn({mask=[HUP INT QUIT PIPE ALRM TERM TSTP]}) = -1 EINTR (Interrupted system call)
futex(0x55efc6e5266c, FUTEX_WAKE_PRIVATE, 2147483647) = 1
futex(0x55efc6e526a8, FUTEX_WAIT_PRIVATE, 0, NULL) = 0
futex(0x55efc6e52e00, FUTEX_WAKE_PRIVATE, 1) = 0
futex(0x55efc6e526ac, FUTEX_WAIT_PRIVATE, 0, NULL