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zend_signal_handler_defer crashes on apache shutdown #10015

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zend_signal_handler_defer crashes on apache shutdown#10015
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BugSAPI: apache2handlerStatus: Needs Triage

Description

@psumbera
psumbera
opened on Nov 28, 2022

Description

Core dump is generated during Apache shutdown.

Seems to be the same incarnation of:
https://bugs.php.net/bug.php?id=78619

This time on Solaris:

   7fc096c1fac61 libphp8.0.so`zend_signal_handler_defer+0x50(1, 7fc096c1fbb00, 7fc096c1fb820, 7fc097d02db70, 0, 7fc09776180a0)
   7fc096c1fad11 libc.so.1`__sighndlr+0xc(1, 7fc096c1fbb00, 7fc096c1fb820, 7fc097741d424, 0, 7fc097c9247c0)
   7fc096c1fadc1 libc.so.1`call_user_handler+0x400(fffffff7, 7fc096c1fbb00, 8, 7fc097d02da40, 1, fffffff7)
   7fc096c1faeb1 libc.so.1`sigacthandler+0xd0(1, 7fc096c1fbb00, 7fc096c1fb820, 34, 1, 7fc097c9247c0)
   7fc096c1fb401 libc.so.1`_portfs+8(8, e4aa7e2068, 34, 7fc096c1fbd70, 0, 0)
   7fc096c1fb4c1 libapr-1.so.0.7.0`impl_pollset_poll+0x284(e4aa7e1f58, ffffffffffffffff, 7fc096c1fbea4, 7fc096c1fbe80, e4aa7e1fb0, e4aa7e2068)
   7fc096c1fb591 mod_mpm_event.so`listener_thread+0x6b8(3, 7fc097bf00100, 7fc097be175fc, 7fc097be16000, 4e2e, 1117f)
   7fc096c1fb6f1 libc.so.1`_lwp_start(0, 0, 0, 0, 0, 0)

PHP Version

PHP 8.0

Operating System

Solaris 11.4

Activity

  1. psumbera
    added
    Bug
    Status: Needs Triage
    on Nov 28, 2022

  2. cmb69 commented on Nov 28, 2022

    @cmb69
    cmb69
    on Nov 28, 2022
    Member

    Indeed, possibly a duplicate of https://bugs.php.net/bug.php?id=78619.

    Anyhow, since PHP 8.0 is no longer actively supported, does this happen on PHP 8.1 too?

  3. cmb69
    added
    SAPI: apache2handler
    Status: Needs Feedback
    and removed
    Status: Needs Triage
    on Nov 28, 2022

  4. cmb69 commented on Nov 30, 2022

    @cmb69
    cmb69
    on Nov 30, 2022
    Member

    Might also be related to #8789.

  5. psumbera commented on Dec 1, 2022

    @psumbera
    psumbera
    on Dec 1, 2022
    ContributorAuthor

    I can reproduce it with PHP 8.1 too. It's actually very easy:

    cp /etc/apache2/2.4/samples-conf.d/php8.1.conf /etc/apache2/2.4/conf.d/
/usr/apache2/2.4/bin/apachectl start
cat > /var/apache2/2.4/htdocs/phpinfo.php <<EOF
<?php
phpinfo();
?>
EOF
wget localhost/phpinfo.php& /usr/apache2/2.4/bin/apachectl graceful

    # cat /var/apache2/2.4/logs/error_log
[Thu Dec 01 15:05:16.261105 2022] [mpm_event:notice] [pid 7077:tid 1] AH00489: Apache/2.4.54 (Unix) PHP/8.1.9 configured -- resuming normal operations
[Thu Dec 01 15:05:16.261856 2022] [core:notice] [pid 7077:tid 1] AH00094: Command line: '/usr/apache2/2.4/bin/httpd'
[Thu Dec 01 15:05:25.824091 2022] [mpm_event:notice] [pid 7077:tid 1] AH00493: SIGUSR1 received.  Doing graceful restart
[Thu Dec 01 15:05:25.880343 2022] [mpm_event:notice] [pid 7077:tid 1] AH00489: Apache/2.4.54 (Unix) PHP/8.1.9 configured -- resuming normal operations
[Thu Dec 01 15:05:25.880432 2022] [core:notice] [pid 7077:tid 1] AH00094: Command line: '/usr/apache2/2.4/bin/httpd'
[Thu Dec 01 15:05:32.888902 2022] [core:notice] [pid 7077:tid 1] AH00051: child pid 7079 exit signal Segmentation fault (11), possible coredump in /usr/apache2/2.4
  6. github-actions
    added
    Status: Needs Triage
    and removed
    Status: Needs Feedback
    on Dec 1, 2022

  7. arnaud-lb commented on Dec 2, 2022

    @arnaud-lb
    arnaud-lb
    on Dec 2, 2022
    Member

    Seems to be the same issue as #9649: the signal is delivered to a thread that didn't execute PHP yet. It crashes when zend_signal_handler_defer access thread globals.

    0x00007f338867185e in zend_signal_handler_defer (signo=1, siginfo=0x7f3341ffa0b0, context=0x7f3341ff9f80) at /php-src/Zend/zend_signal.c:96
96		if (EXPECTED(SIGG(active))) {
(gdb) bt
#0  0x00007f338867185e in zend_signal_handler_defer (signo=1, siginfo=0x7f3341ffa0b0, context=0x7f3341ff9f80) at /php-src/Zend/zend_signal.c:96
#1  <signal handler called>
#2  0x00007f338961cfde in epoll_wait (epfd=8, events=0x7f33889a9620, maxevents=52, timeout=5000) at ../sysdeps/unix/sysv/linux/epoll_wait.c:30
#3  0x00007f33897476b0 in ?? () from /lib/x86_64-linux-gnu/libapr-1.so.0
#4  0x00007f3389383be8 in ?? () from /usr/lib/apache2/modules/mod_mpm_event.so
#5  0x00007f338958bb43 in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:442
#6  0x00007f338961da00 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
(gdb) list
91			zend_signal_handler(signo, siginfo, context);
92			return;
93		}
94	#endif
95	
96		if (EXPECTED(SIGG(active))) {
97			if (UNEXPECTED(SIGG(depth) == 0)) { /* try to handle signal */
98				if (UNEXPECTED(SIGG(blocked))) {
99					SIGG(blocked) = 0;
100				}

    This has been fixed in master by #9766, however in hindsight this may not be ideal in this context.

  8. jtojnar
    added a commit that references this issue on Jan 14, 2023

    theo: Use php-fpm instead of mod_php

    76aa389

  9. psumbera commented on Jan 30, 2023

    @psumbera
    psumbera
    on Jan 30, 2023
    ContributorAuthor

    This has been fixed in master by #9766, however in hindsight this may not be ideal in this context.

    I have applied above pull request and I indeed cannot reproduce the issue (with PHP 8.2).

    Will this be back ported to versions 8.1 and 8.2?

  10. ndossche
    closed this as completedin 06ae750on Mar 18, 2023
  11. ndossche
    added a commit that references this issue on Mar 18, 2023

    Merge branch 'PHP-8.2'

    33dd226
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