Bug 15345 – Perl segfaults in perlio

• Status: RESOLVED FIXED
• Product: Gentoo Linux

[Description Shevek 2003-02-08 19:57:39 UTC]

Install Term::ReadLine::Gnu
Run CPAN.
Do anything nontrivial.
Quit CPAN.

Perl segfaults.

[Comment 1 Shevek 2003-02-08 19:58:24 UTC]

Created attachment 8061 [details]
A log of it all going wrong in gdb

[Comment 2 Shevek 2003-02-08 19:58:54 UTC]

Created attachment 8062 [details]
A PERLIO_DEBUG log of it all going wrong

[Comment 3 J Robert Ray 2003-02-09 00:56:53 UTC]

Please paste output from 'emerge info'.

[Comment 4 Shevek 2003-02-09 08:36:50 UTC]

Created attachment 8085 [details]
output of "emerge info"

Perl wasn't actually installed using emerge because that always segfaults.
However, I did apply both gentoo patches and reinstall both libperl and perl
from a gentoo-compatible source tree.

[Comment 5 Shevek 2003-02-09 08:38:03 UTC]

Created attachment 8086 [details]
The script used to patch my perl source tree

See comments in "emergeinfo" attachment.

[Comment 6 Shevek 2003-02-09 08:39:00 UTC]

Created attachment 8087 [details]
The script used to configure perl

Someone in the perl development team suggested that -fomit-frame-pointer might
help. It didn't. But since gdb can debug without a frame pointer, I tried it.

[Comment 7 Shevek 2003-02-09 08:48:00 UTC]

Created attachment 8088 [details]
Log of it all going wrong in valgrind

This almost seems to be the most telling because if you consider the layout of
a stdio structure, this would seem to be attempting to close the same fd twice.
I should therefore see an error from strace on the close() on the fd?

[Comment 8 Shevek 2003-02-09 08:59:21 UTC]

This bug has Perl rt ticket number 20793.

The last few lines of strace look like:
munmap(0x40324000, 266240)              = 0
munmap(0x40468000, 266240)              = 0
close(3)                                = 0
munmap(0x40313000, 4096)                = 0
close(4)                                = 0
close(4)                                = -1 EBADF (Bad file descriptor)
munmap(0x40314000, 4096)                = 0
--- SIGSEGV (Segmentation fault) ---
+++ killed by SIGSEGV +++

So it is closing a descriptor twice. It appears that this is because T::RL::Gnu is causing the descriptor to go refcount -1.

Note that the descriptor numbers differ between running perl in gdb and running it under strace or valgrind.

[Comment 9 J Robert Ray 2003-06-26 00:13:22 UTC]

Reassigning bugs due to lack of time.

[Comment 10 Shevek 2003-06-26 05:19:03 UTC]

This is now a problem for the Perl maintainers, I think. It's gone away in the latest gentoos, but the code surrounding it isn't pretty.

I have passed the relevant information on to rt.perl.

S.

[Comment 11 Michael Cummings (RETIRED) 2003-08-22 05:28:08 UTC]

is this still an open issue?

[Comment 12 Shevek 2003-08-23 05:43:17 UTC]

Don't think so. rt.perl.<whatever> and Hiro got onto it.

[Comment 13 Michael Cummings (RETIRED) 2003-10-06 05:33:16 UTC]

closed for inactivity/upstream action