From: Stephane Chazelas <stephane.chazelas@gmail.com>
To: Zsh hackers list <zsh-workers@zsh.org>
Subject: kill %jobspec tries to kill dead processes
Date: Fri, 5 Jan 2018 12:46:02 +0000 [thread overview]
Message-ID: <20180105124602.GB16078@chaz.gmail.com> (raw)
Hi,
kill %jobspec
usually avoids the problem when kill $pid may kill the wrong
process when it may have been reused. However, in:
sleep 1 | sleep 3 & sleep 2
kill %"sleep 1"
kill still tries to kill the process that was running sleep 1
even though the shell knows it has died:
$ strace -e kill zsh -c 'sleep 1 | sleep 3 & ps -f; sleep 2; printf "%s => %s\n" "${(@kv)jobstates}"; kill %"sleep 1"'
UID PID PPID C STIME TTY TIME CMD
chazelas 8175 14816 0 12:37 pts/4 00:00:00 strace -e kill zsh -c sleep 1 | sleep 3 & ps -f; sleep 2; printf "%s => %s\n" "${(@kv)jobstates}"; kill %"sleep 1"
chazelas 8177 8175 0 12:37 pts/4 00:00:00 zsh -c sleep 1 | sleep 3 & ps -f; sleep 2; printf "%s => %s\n" "${(@kv)jobstates}"; kill %"sleep 1"
chazelas 8178 8177 0 12:37 pts/4 00:00:00 sleep 1
chazelas 8179 8177 0 12:37 pts/4 00:00:00 sleep 3
chazelas 8180 8177 0 12:37 pts/4 00:00:00 ps -f
chazelas 14816 14812 0 Jan03 pts/4 00:00:01 /bin/zsh
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=8180, si_uid=1000, si_status=0, si_utime=0, si_stime=2} ---
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=8178, si_uid=1000, si_status=0, si_utime=0, si_stime=0} ---
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=8181, si_uid=1000, si_status=0, si_utime=0, si_stime=0} ---
1 => running:+:8178=done:8179=running
kill(8178, SIGTERM) = -1 ESRCH (No such process)
kill(8179, SIGTERM) = 0
+++ exited with 0 +++
See how 8178 was known to be "done", but is still killed.
mksh has the same issue. bash is worse in that it doesn't
attempt to kill the sleep 3 process. ksh93 segfaults when I try
the same thing there.
--
Stephane
next reply other threads:[~2018-01-05 12:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-05 12:46 Stephane Chazelas [this message]
2018-01-05 23:21 ` Stephane Chazelas
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