Dear Maintainer,
A zsh process dumped core when the login session was ended (likely due
to a failed network connection). Here are the relevant logs:
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May 14 17:56:27 host sshd[1733250]: pam_unix(sshd:session): session closed for user
May 14 17:56:27 host systemd-logind[566]: Session 18 logged out. Waiting for processes to exit.
May 14 17:56:27 host kernel: show_signal_msg: 1 callbacks suppressed
May 14 17:56:27 host kernel: zsh[1733257]: segfault at 0 ip 0000558b81d54b3e sp 00007ffc254531f0 error 6 in zsh[558b81cc8000+9a000] likely on CPU 1 (core 0, socket 1)
May 14 17:56:27 host kernel: Code: b6 13 48 8d 41 01 48 83 c3 01 83 f2 20 88 51 01 48 8d 48 01 48 39 de 74 1c 0f b6 13 f6 44 57 01 10 75 d9 48 89 c8 48 83 c3 01 <88> 11 48 8d 48 01 48 39 de 75 e4 c6 01 00 48 83 c4 18 4c 89 e0 5b
May 14 17:56:27 host systemd-coredump[3885063]: Process 1733257 (zsh) of user 1000 dumped core.
May 14 17:56:27 host systemd-logind[566]: Removed session 18.
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Here is the relevant coredump info:
PID: 1733257 (zsh)
Signal: 11 (SEGV)
Timestamp: Wed 2025-05-14 17:56:27 PDT
Command Line: -zsh
Executable: /usr/bin/zsh
Control Group: /user.slice/user-1000.slice/session-18.scope
Unit: session-18.scope
Slice: user-1000.slice
Session: 18
Message: Process 1733257 (zsh) of user 1000 dumped core.
Stack trace of thread 1733257:
#0 0x0000558b81d54b3e wcs_nicechar_sel (zsh + 0xa3b3e)
#1 0x0000558b81d59346 mb_niceformat (zsh + 0xa8346)
#2 0x0000558b81d59a2d n/a (zsh + 0xa8a2d)
#3 0x0000558b81d59b5a zerr (zsh + 0xa8b5a)
#4 0x0000558b81d0bf6d update_job (zsh + 0x5af6d)
#5 0x0000558b81d442f4 wait_for_processes (zsh + 0x932f4)
#6 0x0000558b81d43dd5 zhandler (zsh + 0x92dd5)
#7 0x0000558b81d1bbbe zrealloc (zsh + 0x6abbe)
#8 0x0000558b81d54a86 wcs_nicechar_sel (zsh + 0xa3a86)
#9 0x0000558b81d59346 mb_niceformat (zsh + 0xa8346)
#10 0x0000558b81d59a2d n/a (zsh + 0xa8a2d)
#11 0x0000558b81d5a05a zwarn (zsh + 0xa905a)
#12 0x0000558b81cdf47a zexit (zsh + 0x2e47a)
#13 0x0000558b81d43f89 zhandler (zsh + 0x92f89)
#14 0x00007f0b419f7050 n/a (libc.so.6 + 0x3c050)
#15 0x00007f0b419f72d5 __sigsuspend (libc.so.6 + 0x3c2d5)
#16 0x0000558b81d43367 signal_suspend (zsh + 0x92367)
#17 0x0000558b81d0c464 n/a (zsh + 0x5b464)
#18 0x0000558b81d0cc64 waitjobs (zsh + 0x5bc64)
#19 0x0000558b81cec1e2 n/a (zsh + 0x3b1e2)
#20 0x0000558b81ced133 execlist (zsh + 0x3c133)
#21 0x0000558b81d156c4 execif (zsh + 0x646c4)
#22 0x0000558b81ce9895 n/a (zsh + 0x38895)
#23 0x0000558b81ceb5ce n/a (zsh + 0x3a5ce)
#24 0x0000558b81ceb97b n/a (zsh + 0x3a97b)
#25 0x0000558b81ced133 execlist (zsh + 0x3c133)
#26 0x0000558b81d15dc7 execcase (zsh + 0x64dc7)
#27 0x0000558b81ce9895 n/a (zsh + 0x38895)
#28 0x0000558b81ceb5ce n/a (zsh + 0x3a5ce)
#29 0x0000558b81ceb97b n/a (zsh + 0x3a97b)
#30 0x0000558b81ced133 execlist (zsh + 0x3c133)
#31 0x0000558b81d1579b execif (zsh + 0x6479b)
#32 0x0000558b81ce9895 n/a (zsh + 0x38895)
#33 0x0000558b81ceb5ce n/a (zsh + 0x3a5ce)
#34 0x0000558b81ceb97b n/a (zsh + 0x3a97b)
#35 0x0000558b81ced133 execlist (zsh + 0x3c133)
#36 0x0000558b81d1579b execif (zsh + 0x6479b)
#37 0x0000558b81ce9895 n/a (zsh + 0x38895)
#38 0x0000558b81ceb5ce n/a (zsh + 0x3a5ce)
#39 0x0000558b81ceb97b n/a (zsh + 0x3a97b)
#40 0x0000558b81ced133 execlist (zsh + 0x3c133)
#41 0x0000558b81ceda02 execode (zsh + 0x3ca02)
#42 0x0000558b81d03c4a loop (zsh + 0x52c4a)
#43 0x0000558b81d06569 source (zsh + 0x55569)
#44 0x0000558b81ccfb31 bin_dot (zsh + 0x1eb31)
#45 0x0000558b81cd8ed3 execbuiltin (zsh + 0x27ed3)
#46 0x0000558b81ceaec7 n/a (zsh + 0x39ec7)
#47 0x0000558b81ceb5ce n/a (zsh + 0x3a5ce)
#48 0x0000558b81ceb97b n/a (zsh + 0x3a97b)
#49 0x0000558b81ced61f execlist (zsh + 0x3c61f)
#50 0x0000558b81ceda02 execode (zsh + 0x3ca02)
#51 0x0000558b81d03c4a loop (zsh + 0x52c4a)
#52 0x0000558b81d06569 source (zsh + 0x55569)
#53 0x0000558b81d06c32 run_init_scripts (zsh + 0x55c32)
#54 0x0000558b81d07956 zsh_main (zsh + 0x56956)
#55 0x00007f0b419e224a n/a (libc.so.6 + 0x2724a)
#56 0x00007f0b419e2305 __libc_start_main (libc.so.6 + 0x27305)
#57 0x0000558b81cc8d31 _start (zsh + 0x17d31)
ELF object binary architecture: AMD x86-64
Kind regards.
* Rob Leslie [Thu May 15, 2025 at 12:18:22PM -0700]: [...] Is that reproducible for you somehow? FTR, there's zsh 5.9-4+b6 with: | * Binary-only non-maintainer upload for amd64; no source changes. | * Rebuild for outdated Built-Using (glibc/2.36-9+deb12u5) And latest Debian point-release 12.11 provides libc6 v2.36-9+deb12u10, wondering whether this would change anything, assuming that it's even reproducible in some way at all. regards -mika-
I can’t say it’s reliably reproducible, however I do have a record of 12 other coredumps across several machines, including one from Debian 11. All have similar stack traces. It looks like libc6 2.36-9+deb12u10 was installed on one machine on 2025-03-15 and a coredump followed on 2025-05-17, so that didn’t seem to change anything. Thanks, -rob
* Rob Leslie [Sun Jun 01, 2025 at 01:07:10PM -0400]: Hm, would be interesting to have steps to reproduce this, I never observed such a behavior on my own. Was the system rebooted in between? Was the system fully upgraded to what Debian v12 provides? Do the ~13 occurences you observed so far have anything in common? regards -mika-
Yes, the system was fully upgraded and rebooted after each upgrade. The only thing I can think is that they were all most likely running a tmux client process (i.e. tmux -u attach -t 1) when they were terminated. All the machines have the byobu package installed and run tmux at login. If you were to try to reproduce, you could install the byobu package and start it from ~/.zprofile like this: _byobu_sourced=1 . /usr/bin/byobu-launch 2>/dev/null || true Then connect to the machine remotely via ssh in a local window and perhaps simulate dropping the connection by closing the window? Thanks, -rob