Re: [mp2] bug report: modperl_env.c

Jie Gao wrote:
> -------------8<---------- Start Bug Report ------------8<----------
> 1. Problem Description:
>
> Apache segmentation faults trying to run a registry script.

Thanks for the detailed report Jie, but how do we reproduce it without the 
test script and relevant configuration?



[...]
> root@host_name/usr/local/apache:> truss -f bin/httpd -k start -DSSL -X
>
>
> ....
>
> 10075/12:       
> open("/usr/local/apache_2.0.49/htdocs/test2/mobile_proxy/nph-proxy.cgi", 
> O_RDONLY) = 13
> 10075/12:       read(13, " # ! / u s r / l o c a l".., 4096)    = 4096
> 10075/12:       close(13)                                       = 0
> 10075/12:       getpid()                                        = 10075 [10074]
> 10075/12:       stat("/usr/local/apache_2.0.49/htdocs/010110A/x-proxy/start", 
> 0xFDBFB4F8) Err#2 ENOENT
> 10075/12:       lstat("/usr", 0xFDBFB488)                       = 0
> 10075/12:       lstat("/usr/local", 0xFDBFB488)                 = 0
> 10075/12:       stat("/usr/local", 0xFDBFB420)                  = 0
> 10075/12:       lstat("/usr/local/apache_2.0.49", 0xFDBFB488)   = 0
> 10075/12:       lstat("/usr/local/apache_2.0.49/htdocs", 0xFDBFB488) = 0
> 10075/12:       lstat("/usr/local/apache_2.0.49/htdocs/010110A", 0xFDBFB488) 
> Err#2 ENOENT
> 10075/12:       dup(14)                                         = 13

what's fd 14? earlier trace?

> 10075/12:       fstat64(13, 0x015E4460)                         = 0
> 10075/12:       fcntl(13, F_SETFD, 0x00000001)                  = 0
> 10075/12:       llseek(14, 0, SEEK_CUR)                         = 1176438
> 10075/12:       close(14)                                       = 0
> 10075/12:       dup(12)                                         = 14
> 10075/12:       fstat64(14, 0x015E4460)                         = 0
> 10075/12:       fcntl(14, F_SETFD, 0x00000001)                  = 0
> 10075/12:       dup(12)                                         = 15
> 10075/12:       close(15)                                       = 0
> 10075/12:       close(12)                                       = 0
> 10075/12:           Incurred fault #6, FLTBOUNDS  %pc = 0xFEA9BBBC
> 10075/12:             siginfo: SIGSEGV SEGV_MAPERR addr=0x00000010
> 10075/12:           Received signal #11, SIGSEGV [default]
> 10075/12:             siginfo: SIGSEGV SEGV_MAPERR addr=0x00000010
>
> ---------------------------------------------------------------------------
>
> root@host_name/usr/local/apache/bin:1008> gdb ./httpd
> GNU gdb 5.0
> Copyright 2000 Free Software Foundation, Inc.
> GDB is free software, covered by the GNU General Public License, and you are
> welcome to change it and/or distribute copies of it under certain conditions.
> Type "show copying" to see the conditions.
> There is absolutely no warranty for GDB.  Type "show warranty" for details.
> This GDB was configured as "sparc-sun-solaris2.9"...
> (gdb) run -X -f /usr/local/apache/conf/httpd.conf -k start -DSSL -X
> Starting program: /u0/local/apache_2.0.49/bin/./httpd -X -f 
> /usr/local/apache/conf/httpd.conf -k start -DSSL -X
> [New LWP 1]
> [New LWP 2]
> [New LWP 3]
> [New LWP 4]
> [New LWP 5]
> [New LWP 6]
> [New LWP 7]
> [New LWP 8]
> [New LWP 9]
> [New LWP 10]
> [New LWP 11]
> [New LWP 12]
> [New LWP 13]
> [LWP 2 exited]
> [New LWP 2]
>
> Program received signal SIGSEGV, Segmentation fault.
> [Switching to LWP 12]
> 0xfea9bbbc in modperl_env_request_tie (my_perl=0x1026fe0, r=0x17a8c78) at 
> modperl_env.c:355
> 355         EnvMgObj = (char *)r;
> (gdb)

and you forgot to run 'bt' or 'where' inside gdb.

Though one needs to be careful with threads. Signals aren't necessarily 
delivered to the thread that has sent the signal. So it's quite possible that 
some other thread has caused the segfault and what you see in gdb is just 
where the thread 12 happened to be at the moment. Are you sure that this is 
the only request you were running?

__________________________________________________________________
Stas Bekman            JAm_pH ------> Just Another mod_perl Hacker
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