Comment 12 for bug 1451524

I think the problem with Timeout and PIPE.
Good trace:
188229 22:29:27.741703379 0 timeout (1035120) < execve res=-2(ENOENT) exe=socat args=-u.TCP-LISTEN:17601,reuseaddr,pf=ipv6.stdio. tid=1035120(timeout) pid=1035120(timeout) ptid=1035119(timeout) cwd=/root fdlimit=1024 pgft_maj=0 pgft_min=21 vm_size=11376 vm_rss=124 vm_swap=0 comm=timeout cgroups=cpuset=/.cpu=/.cpuacct=/.memory=/.devices=/.freezer=/.net_cls=/.blkio=/.perf_... env=TERM=xterm.SHELL=/bin/bash.SSH_CLIENT=2a02:...::154 35644 22.SSH_TTY=/...
188230 22:29:27.741713876 0 timeout (1035120) > execve
188231 22:29:27.741715388 0 timeout (1035120) < execve res=-2(ENOENT) exe=socat args=-u.TCP-LISTEN:17601,reuseaddr,pf=ipv6.stdio. tid=1035120(timeout) pid=1035120(timeout) ptid=1035119(timeout) cwd=/root fdlimit=1024 pgft_maj=0 pgft_min=21 vm_size=11376 vm_rss=124 vm_swap=0 comm=timeout cgroups=cpuset=/.cpu=/.cpuacct=/.memory=/.devices=/.freezer=/.net_cls=/.blkio=/.perf_... env=TERM=xterm.SHELL=/bin/bash.SSH_CLIENT=2a02:...::154 35644 22.SSH_TTY=/...
188232 22:29:27.741725946 0 timeout (1035120) > execve
188233 22:29:27.741732668 0 timeout (1035120) > switch next=10 pgft_maj=0 pgft_min=21 vm_size=11376 vm_rss=124 vm_swap=0
634013 22:29:38.741679491 14 timeout (1035119) < wait4
634014 22:29:38.741681931 14 timeout (1035119) > signaldeliver spid=0 dpid=1035119(timeout) sig=14(SIGALRM)
634015 22:29:38.741705993 14 timeout (1035119) > kill pid=1035120(socat) sig=9(SIGKILL)
634016 22:29:38.741710572 14 timeout (1035119) < kill res=0
634017 22:29:38.741711237 14 timeout (1035119) > kill pid=0 sig=9(SIGKILL)
634018 22:29:38.741712195 14 timeout (1035119) < kill res=0
634019 22:29:38.741712534 14 timeout (1035119) > signaldeliver spid=0 dpid=1035119(timeout) sig=9(SIGKILL)
634023 22:29:38.741818809 14 timeout (1035119) > procexit status=9

Bad session:
8365786 22:32:08.467565817 26 timeout (1039023) > execve
8365787 22:32:08.467570304 26 timeout (1039023) < execve res=-2(ENOENT) exe=socat args=-u.TCP-LISTEN:17601,reuseaddr,pf=ipv6.stdio. tid=1039023(timeout) pid=1039023(timeout) ptid=1039021(timeout) cwd=/tmp/tmp.bpv7VUY5Gt fdlimit=32768 pgft_maj=0 pgft_min=24 vm_size=24016 vm_rss=1048 vm_swap=0 comm=timeout cgroups=cpuset=/.cpu=/.cpuacct=/.memory=/.devices=/.freezer=/.net_cls=/.blkio=/.perf_... env=SHELL=/bin/bash.TERM=screen.SSH_CLIENT=2a02:....::149 37197 22.LD_PRELO...
8365792 22:32:08.467588363 26 timeout (1039023) > execve
8365793 22:32:08.467589419 26 timeout (1039023) < execve res=-2(ENOENT) exe=socat args=-u.TCP-LISTEN:17601,reuseaddr,pf=ipv6.stdio. tid=1039023(timeout) pid=1039023(timeout) ptid=1039021(timeout) cwd=/tmp/tmp.bpv7VUY5Gt fdlimit=32768 pgft_maj=0 pgft_min=24 vm_size=24016 vm_rss=1048 vm_swap=0 comm=timeout cgroups=cpuset=/.cpu=/.cpuacct=/.memory=/.devices=/.freezer=/.net_cls=/.blkio=/.perf_... env=SHELL=/bin/bash.TERM=screen.SSH_CLIENT=2a02:...::149 37197 22.LD_PRELO...
8365797 22:32:08.467606225 26 timeout (1039023) > execve
8365799 22:32:08.467611947 26 timeout (1039023) > switch next=139 pgft_maj=0 pgft_min=24 vm_size=24016 vm_rss=1048 vm_swap=0
8428418 22:32:09.045090061 12 timeout (1039021) < wait4
8428420 22:32:09.045103083 12 timeout (1039021) > close fd=1(<p>)
8428421 22:32:09.045104186 12 timeout (1039021) < close res=0
8428422 22:32:09.045106547 12 timeout (1039021) > close fd=2(<f>/var/log/mysql/mysql.err)
8428423 22:32:09.045106786 12 timeout (1039021) < close res=0
8428424 22:32:09.045124680 12 timeout (1039021) > exit_group
8428429 22:32:09.045330964 12 timeout (1039021) > procexit status=0

xbstream closed PIPE and Timeout exit without sending anything signals.
Maby run: timeout -k 110 100 sh -c 'socat -u TCP-LISTEN:17601,reuseaddr,pf=ipv6 stdio | xbstream -x'; RC=( ${PIPESTATUS[@]} )?