[Bug 1897561] Re: libperl.so.5.30.0 causes nginx to segfault

[Enno Ritz]

Hello everyone,

I have the same issue running the following setup:
Ubuntu 20.04.2 LTS 
kernel 5.4.0-73-generic
nginx/1.18.0
naxsi 1.3 Latest

Both systemctl reload and the reload through letsencrypt potentially triggers this. 
My previous assumption was the usage of naxsi in this, but that's merely an assumption.

Jun 17 23:44:30 localhost kernel: [1893305.871732] show_signal_msg: 20 callbacks suppressed
Jun 17 23:44:30 localhost kernel: [1893305.871753] nginx[209784]: segfault at 41 ip 00007f0ca0922593 sp 00007fff27f6ea60 error 4 in libperl.so.5.30.0[7f0ca08ba000+166000]
Jun 17 23:44:30 localhost kernel: [1893305.871773] Code: 48 89 43 10 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f c3 0f 1f 40 00 0f b6 7f 30 48 c1 e8 03 48 29 f8 48 89 c3 74 89 48 8b 02 <4c> 8b 68 10 4d 85 ed 0f 84 28 01 00 00 0f b6 40 30 49 c1 ed 03 49

Kind regards

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https://bugs.launchpad.net/bugs/1897561

Title:
  libperl.so.5.30.0 causes nginx to segfault

Status in perl package in Ubuntu:
  Confirmed

Bug description:
  [Steps to reproduce]

  1) launch a focal container
  $ lxc launch images:ubuntu/focal focal-1897561
  2) enter the container
  $ lxc shell focal-1897561
  3) install libnginx-mod-http-perl
  # apt-get install -y nginx-core libnginx-mod-http-perl
  4) check nginx journal
  # journalctl -fu nginx &
  5) reload nginx 2-3 times
  # systemctl reload nginx

  Eventually you will see this from the journal:

  Oct 13 17:13:34 focal-1897561 systemd[1]: Reloaded A high performance web server and a reverse proxy server.
  Oct 13 17:13:35 focal-1897561 systemd[1]: nginx.service: Main process exited, code=dumped, status=11/SEGV
  Oct 13 17:13:35 focal-1897561 systemd[1]: nginx.service: Killing process 588 (nginx) with signal SIGKILL.
  Oct 13 17:13:35 focal-1897561 systemd[1]: nginx.service: Killing process 589 (nginx) with signal SIGKILL.
  Oct 13 17:13:35 focal-1897561 systemd[1]: nginx.service: Killing process 588 (nginx) with signal SIGKILL.
  Oct 13 17:13:35 focal-1897561 systemd[1]: nginx.service: Killing process 589 (nginx) with signal SIGKILL.
  Oct 13 17:13:35 focal-1897561 systemd[1]: nginx.service: Failed with result 'core-dump'.

  [Workaround]

  If libnginx-mod-http-perl is not needed, purging it and restarting
  nginx sidesteps the problem.

  [Original bug description]

  Ubuntu 20.04 LTS

  Looks that Perl 5.30 has bug that causes nginx to die, usually occurs
  after "service nginx reload"

  This looks like nginx, but it really is perl issue:
  https://github.com/Perl/perl5/issues/17154

  Fix done in 5.32 (Perl5 commit ffffbf0) and people are asking backport
  to 5.30 to get fix also to nginx.

  Error:
  Sep 28 07:39:43 host kernel: [1340832.811014] nginx[3253005]: segfault at 10 ip 00007fbf3220d593 sp 00007ffd6bba6260 error 4 in libperl.so.5.30.0[7fbf321a5000+166000]

  Symptom: Nginx terminates
  --- 
  ProblemType: Bug
  ApportVersion: 2.20.11-0ubuntu27.9
  Architecture: amd64
  CasperMD5CheckResult: skip
  DistroRelease: Ubuntu 20.04
  Package: perl 5.30.0-9build1
  PackageArchitecture: amd64
  ProcEnviron:
   TERM=xterm
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  ProcVersionSignature: Ubuntu 5.4.0-42.46-generic 5.4.44
  Tags:  focal uec-images
  Uname: Linux 5.4.0-42-generic x86_64
  UpgradeStatus: No upgrade log present (probably fresh install)
  UserGroups: N/A
  _MarkForUpload: True

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