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try setting signal handling to "unsafe" (ie. allow sigs to interrupt
ongoing OP calls) --
export PERL_SIGNALS=unsafe
that may help getting a decent stack trace.
(ps: anyone got a code snippet for the SIGUSR2-gives-stack-trace trick?
that sounds very useful.)
- --j.
Justin Erenkrantz writes:
> As I've mentioned before, we (apache.org) are seeing our qpsmtpd processes
> stuck in an infinite loop. We're using qpsmtpd-forkserver.
>
> At Ask's suggestion, I've placed in Carp::Confess lines - but the program
> isn't accepting signals when we reach this loop state. At all other times,
> it'll respond to SIGUSR2 and print the perl stack trace.
>
> I can't consistently reproduce this; but we get 5-10 perl processes a day
> that are eating up all of our CPU.
>
> Any help is appreciated. If you need/want coredumps, let me know. I'm
> available on AIM if you want to help me debug this in real-time (email me
> for my AIM nick). We have a collection of these processes SIGSTOPed so we
> can examine them.
>
> Does anyone think upgrading to perl 5.8.7 help?
>
> Thanks! -- justin
>
> gdb stack trace:
>
> (gdb) where
> #0 0x281040d2 in Perl_newSVpvn ()
> from /usr/local/lib/perl5/5.8.6/mach/CORE/libperl.so
> #1 0x280e9526 in Perl_magic_setsig ()
> from /usr/local/lib/perl5/5.8.6/mach/CORE/libperl.so
> #2 0x280e782b in Perl_mg_set ()
> from /usr/local/lib/perl5/5.8.6/mach/CORE/libperl.so
> #3 0x280f241d in Perl_pp_sassign ()
> from /usr/local/lib/perl5/5.8.6/mach/CORE/libperl.so
> #4 0x280f1fad in Perl_runops_standard ()
> from /usr/local/lib/perl5/5.8.6/mach/CORE/libperl.so
> #5 0x280a0c26 in S_run_body ()
> from /usr/local/lib/perl5/5.8.6/mach/CORE/libperl.so
> #6 0x280a08b1 in perl_run ()
> from /usr/local/lib/perl5/5.8.6/mach/CORE/libperl.so
> #7 0x08049040 in main ()
>
> pstack output:
>
> 57376: /usr/local/bin/perl5.8.6
> ----------------- thread -1 (running) -----------------
> 0x281040d2 Perl_newSVpvn (80543b0, 4, bfbfec40, 280e9306, 808cad8, 50) + 1e
> 0x280e9526 Perl_magic_setsig (808cb5c, 8098b38, bfbfecd8, 280f67ca,
> 808cad8, 8568044) + 22e
> 0x280e782b Perl_mg_set (808cb5c, 83e8844, 2, 280f238a, 808ff18, 820c094) +
> 6f
> 0x280f241d Perl_pp_sassign (80484b4, bfbfed24, 2804ff2b, 28178564,
> bfbfee34, 9) + a1
> 0x280f1fad Perl_runops_standard (2806a5d8, 28178564, bfbfed88, 280a08b1,
> 1, 0) + 35
> 0x280a0c26 S_run_body (1, 0, 28052cdd, 2807a040, 804a150, bfbfed64) + 12e
> 0x280a08b1 perl_run (804c030, 804a0fc, bfbfedec, 8048fd5, 2806a5d8,
> 2827251c) + 8d
> 0x8049040 main (9, bfbfee34, bfbfee5c, 8048eb2, 8049b14, 0) + d8
> 0x8048ebd _start (bfbfeee4, bfbfeef2, bfbfeef6, bfbfef0b, bfbfef0e,
> bfbfef11) + 85
>
> lsof output:
>
> COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
> perl5.8.6 57376 smtpd cwd VDIR 4,14 512 2956294
> /usr/home/smtpd/qpsmtpd
> perl5.8.6 57376 smtpd rtd VDIR 4,14 512 2 /
> perl5.8.6 57376 smtpd txt VREG 4,14 10076 2190650
> /usr/local/bin/perl
> perl5.8.6 57376 smtpd txt VREG 4,14 142236 455321
> /libexec/ld-elf.so.1
> perl5.8.6 57376 smtpd txt VREG 4,14 1131877 2482217
> /usr/local/lib/perl5/5.8.6/mach/CORE/libperl.so
> perl5.8.6 57376 smtpd txt VREG 4,14 120004 2841954 /lib/libm.so.3
> perl5.8.6 57376 smtpd txt VREG 4,14 28644 2833198
> /lib/libcrypt.so.2
> perl5.8.6 57376 smtpd txt VREG 4,14 43108 2841956
> /lib/libutil.so.4
> perl5.8.6 57376 smtpd txt VREG 4,14 889908 2841961 /lib/libc.so.5
> perl5.8.6 57376 smtpd txt VREG 4,14 7038 2482042
> /usr/local/lib/perl5/5.8.6/mach/auto/Sys/Hostname/Hostname.so
> perl5.8.6 57376 smtpd txt VREG 4,14 17360 2481822
> /usr/local/lib/perl5/5.8.6/mach/auto/IO/IO.so
> perl5.8.6 57376 smtpd txt VREG 4,14 18438 2481805
> /usr/local/lib/perl5/5.8.6/mach/auto/Fcntl/Fcntl.so
> perl5.8.6 57376 smtpd txt VREG 4,14 112273 2481994
> /usr/local/lib/perl5/5.8.6/mach/auto/POSIX/POSIX.so
> perl5.8.6 57376 smtpd txt VREG 4,14 7630 2081259 /
> (/dev/da0s1a)
> perl5.8.6 57376 smtpd txt VREG 4,14 27641 2482012
> /usr/local/lib/perl5/5.8.6/mach/auto/Socket/Socket.so
> perl5.8.6 57376 smtpd 0r VCHR 2,2 0t0 22 /dev/null
> perl5.8.6 57376 smtpd 1u PIPE 0xc3d5622c 0 ->0xc3d56180
> perl5.8.6 57376 smtpd 2u PIPE 0xc3d5622c 0 ->0xc3d56180
> perl5.8.6 57376 smtpd 3r VREG 4,14 6131 2955766
> /usr/home/smtpd/qpsmtpd/qpsmtpd-forkserver
> perl5.8.6 57376 smtpd 5u IPv4 0t0 TCP no PCB,
> CANTSENDMORE, CANTRCVMORE
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