This works fine: dualbus@debian:~$ ~/local/bin/bash -s <<< 'for i in . .; do (~/local/bin/bash -mic ": & wait") ; done' [1] 1629 [1]+ Done : [1] 1631 [1]+ Done :
----- This does not: dualbus@debian:~$ ~/local/bin/bash -s <<< 'for i in . .; do (~/local/bin/bash -mc ": & wait") ; done' [1]+ Done : [1]+ Stopped ~/local/bin/bash -s <<< 'for i in . .; do (~/local/bin/bash -mc ": & wait") ; done' ----- Here's my OS and bash information (bash is 2e4d3851f76a94dfc21af046e0dfd84b954b0f50, from devel) dualbus@debian:~$ cat /etc/debian_version 7.3 dualbus@debian:~$ uname -a Linux debian 3.2.0-4-amd64 #1 SMP Debian 3.2.51-1 x86_64 GNU/Linux dualbus@debian:~$ ~/local/bin/bash --version GNU bash, version 4.3.0(1)-release (x86_64-unknown-linux-gnu) Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software; you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. ----- Here's a sample output from strace when running this (I removed lots of lines, didn't want to flood the list): strace -fo bash-mc.log ~/local/bin/bash -s <<< 'for i in . .; do (~/local/bin/bash -mc ": & wait") ; done' 29747 execve("/home/dualbus/local/bin/bash", ["/home/dualbus/local/bin/bash", "-s"], [/* 24 vars */]) = 0 29747 brk(0) = 0x149c000 29747 rt_sigprocmask(SIG_BLOCK, [INT CHLD], [], 8) = 0 [...] 1st child 29747 clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x7f58bff209d0) = 29748 29747 rt_sigprocmask(SIG_SETMASK, [], <unfinished ...> 29748 rt_sigprocmask(SIG_SETMASK, [], <unfinished ...> 29747 <... rt_sigprocmask resumed> NULL, 8) = 0 29747 rt_sigprocmask(SIG_BLOCK, [CHLD], <unfinished ...> 29748 <... rt_sigprocmask resumed> NULL, 8) = 0 29748 rt_sigaction(SIGTSTP, {SIG_DFL, [], SA_RESTORER, 0x7f58bf5914f0}, <unfinished ...> 29747 <... rt_sigprocmask resumed> [], 8) = 0 29748 <... rt_sigaction resumed> {SIG_DFL, [], 0}, 8) = 0 29747 rt_sigprocmask(SIG_SETMASK, [], <unfinished ...> 29748 rt_sigaction(SIGTTIN, {SIG_DFL, [], SA_RESTORER, 0x7f58bf5914f0}, <unfinished ...> 29747 <... rt_sigprocmask resumed> NULL, 8) = 0 29747 rt_sigprocmask(SIG_BLOCK, [CHLD], <unfinished ...> [...] lots of stuff 29748 open("/home/dualbus/local/share/locale/en_US/LC_MESSAGES/bash.mo", O_RDONLY) = -1 ENOENT (No such file or directory) 29748 open("/home/dualbus/local/share/locale/en/LC_MESSAGES/bash.mo", O_RDONLY) = -1 ENOENT (No such file or directory) 29748 write(2, "[1]+ Done :\n", 32) = 32 29748 rt_sigprocmask(SIG_BLOCK, [CHLD], [CHLD], 8) = 0 29748 rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0 29748 rt_sigprocmask(SIG_BLOCK, [CHLD], [CHLD], 8) = 0 29748 rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0 29748 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 29748 --- SIGCHLD (Child exited) @ 0 (0) --- 29748 wait4(-1, 0x7fff8fdcad80, WNOHANG|WSTOPPED|WCONTINUED, NULL) = -1 ECHILD (No child processes) 29748 rt_sigreturn(0xffffffffffffffff) = 0 29748 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0 29748 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 29748 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0 29748 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 29748 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0 29748 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 29748 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0 29748 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 29748 setpgid(0, 29746) = 0 29748 exit_group(0) = ? 29747 <... wait4 resumed> [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 29748 29747 rt_sigaction(SIGINT, {SIG_DFL, [], SA_RESTORER, 0x7f58bf5914f0}, {0x460380, [], SA_RESTORER, 0x7f58bf5914f0}, 8) = 0 29747 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 29747 --- SIGCHLD (Child exited) @ 0 (0) --- 29747 wait4(-1, 0x7ffff870cd80, WNOHANG, NULL) = -1 ECHILD (No child processes) 29747 rt_sigreturn(0xffffffffffffffff) = 0 29747 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0 29747 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 29747 rt_sigprocmask(SIG_BLOCK, [INT CHLD], [], 8) = 0 29747 clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x7f58bff209d0) = 29750 29747 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 29747 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0 29747 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 29747 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0 29747 rt_sigaction(SIGINT, {0x460380, [], SA_RESTORER, 0x7f58bf5914f0}, {SIG_DFL, [], SA_RESTORER, 0x7f58bf5914f0}, 8) = 0 29747 wait4(-1, <unfinished ...> 29750 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 29750 rt_sigaction(SIGTSTP, {SIG_DFL, [], SA_RESTORER, 0x7f58bf5914f0}, {SIG_DFL, [], 0}, 8) = 0 29750 rt_sigaction(SIGTTIN, {SIG_DFL, [], SA_RESTORER, 0x7f58bf5914f0}, {SIG_DFL, [], 0}, 8) = 0 29750 rt_sigaction(SIGTTOU, {SIG_DFL, [], SA_RESTORER, 0x7f58bf5914f0}, {SIG_DFL, [], 0}, 8) = 0 29750 rt_sigaction(SIGINT, {SIG_DFL, [], SA_RESTORER, 0x7f58bf5914f0}, {SIG_DFL, [], SA_RESTORER, 0x7f58bf5914f0}, 8) = 0 29750 rt_sigaction(SIGQUIT, {SIG_DFL, [], SA_RESTORER, 0x7f58bf5914f0}, {SIG_IGN, [], SA_RESTORER, 0x7f58bf5914f0}, 8) = 0 29750 rt_sigaction(SIGCHLD, {SIG_DFL, [], SA_RESTORER|SA_RESTART, 0x7f58bf5914f0}, {0x4628b0, [], SA_RESTORER|SA_RESTART, 0x7f58bf5914f0}, 8) = 0 29750 rt_sigaction(SIGCHLD, {0x4628b0, [], SA_RESTORER|SA_RESTART, 0x7f58bf5914f0}, {SIG_DFL, [], SA_RESTORER|SA_RESTART, 0x7f58bf5914f0}, 8) = 0 29750 rt_sigaction(SIGINT, {0x4862b0, [], SA_RESTORER, 0x7f58bf5914f0}, {SIG_DFL, [], SA_RESTORER, 0x7f58bf5914f0}, 8) = 0 29750 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0 29750 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 29750 rt_sigprocmask(SIG_BLOCK, ~[RTMIN RT_1], [], 8) = 0 29750 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 29750 rt_sigaction(SIGINT, {SIG_DFL, [], SA_RESTORER, 0x7f58bf5914f0}, {0x4862b0, [], SA_RESTORER, 0x7f58bf5914f0}, 8) = 0 29750 rt_sigaction(SIGQUIT, {SIG_DFL, [], SA_RESTORER, 0x7f58bf5914f0}, {SIG_DFL, [], SA_RESTORER, 0x7f58bf5914f0}, 8) = 0 29750 rt_sigaction(SIGCHLD, {SIG_DFL, [], SA_RESTORER|SA_RESTART, 0x7f58bf5914f0}, {0x4628b0, [], SA_RESTORER|SA_RESTART, 0x7f58bf5914f0}, 8) = 0 29750 execve("/home/dualbus/local/bin/bash", ["/home/dualbus/local/bin/bash", "-mc", ": & wait"], [/* 24 vars */]) = 0 29750 brk(0) = 0x9a8000 [...] before the loop 29750 stat(".", {st_mode=S_IFDIR|0770, st_size=4096, ...}) = 0 29750 getpid() = 29750 29750 open("/usr/lib/x86_64-linux-gnu/gconv/gconv-modules.cache", O_RDONLY) = 3 29750 fstat(3, {st_mode=S_IFREG|0644, st_size=26066, ...}) = 0 29750 mmap(NULL, 26066, PROT_READ, MAP_SHARED, 3, 0) = 0x7f276537f000 29750 close(3) = 0 29750 getppid() = 29747 29750 brk(0x9af000) = 0x9af000 29750 brk(0x9b0000) = 0x9b0000 29750 brk(0x9b1000) = 0x9b1000 29750 getpgrp() = 29746 29750 dup(2) = 3 29750 getrlimit(RLIMIT_NOFILE, {rlim_cur=1024, rlim_max=4*1024}) = 0 29750 fcntl(255, F_GETFD) = -1 EBADF (Bad file descriptor) 29750 dup2(3, 255) = 255 29750 close(3) = 0 29750 ioctl(255, TIOCGPGRP, [29748]) = 0 29750 rt_sigaction(SIGTTIN, {SIG_DFL, [], SA_RESTORER, 0x7f27649e34f0}, {0x462a10, [], SA_RESTORER, 0x7f27649e34f0}, 8) = 0 29750 kill(0, SIGTTIN) = 0 29750 --- SIGTTIN (Stopped (tty input)) @ 0 (0) --- 29750 --- SIGTTIN (Stopped (tty input)) @ 0 (0) --- 29750 rt_sigaction(SIGTTIN, {0x462a10, [], SA_RESTORER, 0x7f27649e34f0}, {SIG_DFL, [], SA_RESTORER, 0x7f27649e34f0}, 8) = 0 29750 ioctl(255, TIOCGPGRP, [29748]) = 0 29750 rt_sigaction(SIGTTIN, {SIG_DFL, [], SA_RESTORER, 0x7f27649e34f0}, {0x462a10, [], SA_RESTORER, 0x7f27649e34f0}, 8) = 0 29750 kill(0, SIGTTIN) = 0 29750 --- SIGTTIN (Stopped (tty input)) @ 0 (0) --- 29750 --- SIGTTIN (Stopped (tty input)) @ 0 (0) --- 29750 rt_sigaction(SIGTTIN, {0x462a10, [], SA_RESTORER, 0x7f27649e34f0}, {SIG_DFL, [], SA_RESTORER, 0x7f27649e34f0}, 8) = 0 29750 ioctl(255, TIOCGPGRP, [29748]) = 0 29750 rt_sigaction(SIGTTIN, {SIG_DFL, [], SA_RESTORER, 0x7f27649e34f0}, {0x462a10, [], SA_RESTORER, 0x7f27649e34f0}, 8) = 0 29750 kill(0, SIGTTIN) = 0 29750 --- SIGTTIN (Stopped (tty input)) @ 0 (0) --- 29750 --- SIGTTIN (Stopped (tty input)) @ 0 (0) --- 29750 rt_sigaction(SIGTTIN, {0x462a10, [], SA_RESTORER, 0x7f27649e34f0}, {SIG_DFL, [], SA_RESTORER, 0x7f27649e34f0}, 8) = 0 29750 ioctl(255, TIOCGPGRP, [29748]) = 0 29750 rt_sigaction(SIGTTIN, {SIG_DFL, [], SA_RESTORER, 0x7f27649e34f0}, {0x462a10, [], SA_RESTORER, 0x7f27649e34f0}, 8) = 0 29750 kill(0, SIGTTIN) = 0 29750 --- SIGTTIN (Stopped (tty input)) @ 0 (0) --- 29750 --- SIGTTIN (Stopped (tty input)) @ 0 (0) --- 29750 rt_sigaction(SIGTTIN, {0x462a10, [], SA_RESTORER, 0x7f27649e34f0}, {SIG_DFL, [], SA_RESTORER, 0x7f27649e34f0}, 8) = 0 29750 ioctl(255, TIOCGPGRP, [29748]) = 0 29750 rt_sigaction(SIGTTIN, {SIG_DFL, [], SA_RESTORER, 0x7f27649e34f0}, {0x462a10, [], SA_RESTORER, 0x7f27649e34f0}, 8) = 0 [...] goes on forever I can provide the full log in case it's needed. Beware that this bug seems to hang strace (had to kill -9 it) and when run under gdb while set follow-fork-mode child, gdb seemed to die, and then two shells were running at the same time. By the way, are compressed log file attachments OK in this list? -- Eduardo Alan Bustamante López
