Comment 21 for bug 1386666

Oct 31 19:52:43 localhost cloud-init: time strace -ffffffffff su root -c 'echo test' >> /tmp/allo 2>&1
Oct 31 19:52:43 localhost cloud-init: real 0m25.071s
Oct 31 19:52:43 localhost cloud-init: user 0m0.011s
Oct 31 19:52:43 localhost cloud-init: sys 0m0.025s

The issue is exactly there:
20:11:46 sendto(6, "BEGIN\r\n", 7, MSG_NOSIGNAL, NULL, 0) = 7
20:11:46 poll([{fd=6, events=POLLIN|POLLOUT}], 1, 4294967295) = 1 ([{fd=6, revents=POLLOUT}])
20:11:46 sendmsg(6, {msg_name(0)=NULL, msg_iov(2)=[{"l\1\0\1\0\0\0\0\1\0\0\0n\0\0\0\1\1o\0\25\0\0\0/org/fre"..., 128}, {"", 0}], msg_controllen=0, msg_flags=0}, MSG_NOSIGNAL) = 128
20:11:46 clock_gettime(CLOCK_MONOTONIC, {726, 288363024}) = 0
20:11:46 poll([{fd=6, events=POLLIN}], 1, 25000) = 1 ([{fd=6, revents=POLLIN}])
20:11:46 recvmsg(6, {msg_name(0)=NULL, msg_iov(1)=[{"l\2\1\1\n\0\0\0\1\0\0\0=\0\0\0\6\1s\0\5\0\0\0:1.32\0\0\0"..., 2048}], msg_controllen=0, msg_flags=MSG_CMSG_CLOEXEC}, MSG_CMSG_CLOEXEC) = 260
20:11:46 recvmsg(6, 0x7fff6b6f0370, MSG_CMSG_CLOEXEC) = -1 EAGAIN (Resource temporarily unavailable)
20:11:46 sendmsg(6, {msg_name(0)=NULL, msg_iov(2)=[{"l\1\0\1a\0\0\0\2\0\0\0\222\0\0\0\1\1o\0\27\0\0\0/org/fre"..., 168}, {"\0\0\0\0\266%\0\0\2\0\0\0su\0\0\v\0\0\0unspecified\0"..., 97}], msg_controllen=0, msg_flags=0}, MSG_NOSIGNAL) = 265
20:11:46 clock_gettime(CLOCK_MONOTONIC, {726, 304256758}) = 0
20:11:46 poll([{fd=6, events=POLLIN}], 1, 25000) = 0 (Timeout)
20:12:11 clock_gettime(CLOCK_MONOTONIC, {751, 330416732}) = 0
20:12:11 socket(PF_LOCAL, SOCK_DGRAM|SOCK_CLOEXEC, 0) = 7
20:12:11 connect(7, {sa_family=AF_LOCAL, sun_path="/dev/log"}, 110) = 0
20:12:11 sendto(7, "<83>Oct 31 20:12:11 su: pam_syst"..., 285, MSG_NOSIGNAL, NULL, 0) = 285
20:12:11 close(6) = 0
20:12:11 getuid() = 0