Your message dated Sun, 7 Aug 2022 22:47:51 +0530 with message-id <Yu/zv/[email protected]> and subject line Closing bug has caused the Debian Bug report #965072, regarding ksh93: posix_spawn-related exec format error to be marked as done.
This means that you claim that the problem has been dealt with. If this is not the case it is now your responsibility to reopen the Bug report if necessary, and/or fix the problem forthwith. (NB: If you are a system administrator and have no idea what this message is talking about, this may indicate a serious mail system misconfiguration somewhere. Please contact [email protected] immediately.) -- 965072: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=965072 Debian Bug Tracking System Contact [email protected] with problems
--- Begin Message ---Package: ksh Version: 93u+20120801-3.1 Severity: important (stretch-i386)tglase@tglase:~ $ ksh93 ksh93$ cat TODO | while read line; do ls; done ls: ls: cannot execute [Exec format error] […] We got this as bugreport in #ksh on IRC, and I can reproduce it, so forwarding here: 22:43 -!- CrystalMath [~coderain@reactos/developer/theflash] has joined #ksh 22:43 < CrystalMath> hi all 22:43 < CrystalMath> sometimes, with ksh93, i get a strange NOEXEC error 22:43 < CrystalMath> err, ENOEXEC, i mean 23:03 < CrystalMath> looking at ksh through strace, it seems that it happens when setpgid() fails with -EPERM 23:03 < CrystalMath> possibly a race condition 23:35 < CrystalMath> seems to be a bug in posix_spawn() 23:35 < CrystalMath> i'll try a newer version of ksh93 23:41 < CrystalMath> nope, the latest version still fails 23:42 < CrystalMath> how did people miss such a glaring bug? 23:46 < twkm> i don't think i've ever seen such. is this for a something with resource constraints? 23:47 < CrystalMath> no 23:48 < CrystalMath> regular normal computer 23:48 < CrystalMath> posix_spawn()'s strange failure appears to be -EPERM 23:48 < CrystalMath> i suspect a pid-related race condition 23:49 < twkm> so not a container, jail, or nproc (ulimit -u) set low? 23:49 < CrystalMath> ulimit -u is 61777 23:49 < CrystalMath> not a container, jail, nor chroot 23:53 < CrystalMath> just cat any file into while read line; do ls; done 23:53 < CrystalMath> ls: ls: cannot execute [Exec format error] 23:55 < CrystalMath> hmmmmm 23:55 < CrystalMath> can't seem to replicate in slackware 23:55 < CrystalMath> only happens in debian 23:55 < twkm> failing disk. 23:55 < CrystalMath> can't be 23:55 < twkm> not ksh at any rate. that's the kernel whining. 23:55 < CrystalMath> it is ksh 23:55 < twkm> it's merely reported by ksh. 23:56 < CrystalMath> i traced it with strace 23:56 < CrystalMath> what happens 23:56 < CrystalMath> is that posix_spawn() fails 23:56 < CrystalMath> and ksh tries to interpret it as a script 23:56 < CrystalMath> but it's an ELF file 23:56 < CrystalMath> the weird part is the failure of posix_spawn() which i cannot explain 23:57 < CrystalMath> inside a slackware chroot i have, the bug does not occur, which is why i will look closely at the version number now 23:57 < CrystalMath> both report: sh (AT&T Research) 93u+ 2012-08-01 23:59 < CrystalMath> how do i tell ksh not to load my ~/.kshrc? Day changed to 15 Jul 2020 00:00 < twkm> if the kernel reports it can't exec the script ksh will attempt to interpret it. 00:01 < CrystalMath> but the error was EPERM 00:02 < twkm> picking the system i happen to be on at the moment: 00:02 < twkm> EPERM The filesystem is mounted nosuid, the user is not the superuser, 00:02 < twkm> and the file has the set-user-ID or set-group-ID bit set. 00:02 < twkm> EPERM The process is being traced, the user is not the superuser and 00:02 < twkm> the file has the set-user-ID or set-group-ID bit set. 00:03 < CrystalMath> 24899 setpgid(0, 24898) = -1 EPERM (Operation not permitted) 00:03 < CrystalMath> this is the strange failure 00:03 < CrystalMath> whenever this happens, down the line, ksh seems to try to interpret it as a script 00:04 < twkm> because [repeat:] if the kernel reports it can't exec the script ksh will attempt to interpret it. 00:04 < CrystalMath> there was no call to execve() 00:04 < twkm> your systems docs for why setpgid returned eperm are germane. 00:05 < twkm> no exec because something getting ready for the exec failed. 00:12 < CrystalMath> i changed the code of ksh to use something other than posix_spawn() 00:14 < CrystalMath> rebuilding now 00:14 < CrystalMath> it has several options in the code but it prefers posix_spawn() if it's available, if removed that part with #if 0 00:20 < CrystalMath> that fixed it! 00:20 < CrystalMath> the modified version i made does not have the probelm 00:20 < CrystalMath> *problem 00:20 < CrystalMath> i have no idea why posix_spawn() is broken on my system 00:21 < CrystalMath> after quite of bit of hammering ksh, not a single exec format error! 00:21 < CrystalMath> before it was very common 00:35 < CrystalMath> either way i conclude that this bug was not in ksh but in glibc 00:36 < CrystalMath> because the call to posix_spawn() was correct, but didn't work as expected 14:26 < mirabilos> can reproduce on Debian 14:26 < mirabilos> also on stock ksh93u but not ksh93v 14:26 < mirabilos> ksh93t just stops itself 14:27 < mirabilos> $ ksh93t 14:27 < mirabilos> $ cat TODO | while read line; do ls; done 14:27 < mirabilos> [2] + Stopped (tty output) \ksh93t This happens in stretch, buster and sid *AT LEAST*. So, this might be a bug in ksh93 and/or one in glibc. If it’s just one in glibc, I’d suggest cloning this bug and reassigning it against glibc while treating the bug against ksh93 as a request to change building it to avoid posix_spawn. Reassigning also means figuring out some testcase that triggers the posix_spawn failure which may be tricky. -- System Information: Debian Release: 9.12 APT prefers oldstable-updates APT policy: (500, 'oldstable-updates'), (500, 'oldstable') Architecture: i386 (i686) Kernel: Linux 5.7.0-1-amd64 (SMP w/4 CPU cores) Locale: LANG=C, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=C (charmap=UTF-8) Shell: /bin/sh linked to /bin/lksh Init: sysvinit (via /sbin/init) Versions of packages ksh depends on: ii binfmt-support 2.1.6-2 ii libc6 2.24-11+deb9u4 ksh recommends no packages. ksh suggests no packages. -- no debconf information
--- End Message ---
--- Begin Message ---Version: 1.0.0~beta.1-1 Tested and working now. -- Anuradha
--- End Message ---
