Re: gdb/2241: Different errno when program signalled from gdb

Re: gdb/2241: Different errno when program signalled from gdb

[Matthieu CASTET]

The following reply was made to PR gdb/2241; it has been noted by GNATS.

From: Matthieu CASTET <matthieu.castet@parrot.com>
To: gdb-gnats@sources.redhat.com
Cc:  
Subject: Re: gdb/2241: Different errno when program signalled from gdb
Date: Fri, 31 Aug 2007 11:41:23 +0200

 I got the same problem with gdb producing on read syscall, an errno of 
 512 (ERESTARTSYS).
 
 

Re: gdb/2241: Different errno when program signalled from gdb

[Daniel Jacobowitz]

The following reply was made to PR gdb/2241; it has been noted by GNATS.

From: Daniel Jacobowitz <drow@false.org>
To: chris.auston@crsoftwareinc.com
Cc: gdb-gnats@sources.redhat.com
Subject: Re: gdb/2241: Different errno when program signalled from gdb
Date: Mon, 26 Mar 2007 13:33:07 -0400

 On Mon, Mar 26, 2007 at 04:31:44PM -0000, chris.auston@crsoftwareinc.com wrote:
 > Program received signal SIGINT, Interrupt.
 > [Switching to Thread -1208489328 (LWP 22061)]
 > 0x00d958d2 in _dl_sysinfo_int80 () at rtld.c:576
 > 576     relocate_doit (void *a)
 > Current language:  auto; currently c
 > (gdb) sig 2
 > Continuing with signal SIGINT.
 > errno=514
 > 
 > Program exited normally.
 > (gdb) 
 
 FYI, I can reproduce this.  514 is ERESTARTNOHAND, a Linux internal
 errno code used for interrupted syscalls.  We've manually interrupted
 the syscall.
 
 I'm not entirely sure if this should be considered a GDB or kernel
 bug... someone will have to consider how the two should work together.
 It seems like the syscall should have been restarted.
 
 -- 
 Daniel Jacobowitz
 CodeSourcery

gdb/2241: Different errno when program signalled from gdb

[chris.auston]

>Number:         2241
>Category:       gdb
>Synopsis:       Different errno when program signalled from gdb
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Mar 26 17:38:01 BST 2007
>Closed-Date:
>Last-Modified:
>Originator:     chris.auston@crsoftwareinc.com
>Release:        GNU gdb 6.6
>Organization:
>Environment:
Linux doughnuthole.crsoftwareinc.com 2.6.9-42.0.10.EL #1 Tue Feb 27 09:24:42 EST 2007 i686 i686 i386 GNU/Linux

Reading specs from /usr/lib/gcc/i386-redhat-linux/3.4.6/specs
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --disable-checking --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-java-awt=gtk --host=i386-redhat-linux
Thread model: posix
gcc version 3.4.6 20060404 (Red Hat 3.4.6-3)

This GDB was configured as "i686-pc-linux-gnu"...
>Description:
I get a different value for errno when signalling a program in gdb and outside gdb. Running the program by itself and sending SIGINT will yield the correct result EINTR. But when I interrupt gdb and use the "signal 2" command I get errno=514 which is invalid.

I suspect I have a configuration issue, but cannot find any reference for it on the net. It strikes me as a TLS problem since errno should be such a variable.
>How-To-Repeat:
[crsd@doughnuthole gdberr]$ ./gdberr 
Generate SIGINT to interrupt me...
errno=4

[crsd@doughnuthole gdberr]$ gdb gdberr 
GNU gdb 6.6
Copyright (C) 2006 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 "i686-pc-linux-gnu"...
Using host libthread_db library "/lib/tls/libthread_db.so.1".
(gdb) r
Starting program: /home/crsd/gdberr/gdberr 
[Thread debugging using libthread_db enabled]
[New Thread -1208489328 (LWP 22061)]
Generate SIGINT to interrupt me...

Program received signal SIGINT, Interrupt.
[Switching to Thread -1208489328 (LWP 22061)]
0x00d958d2 in _dl_sysinfo_int80 () at rtld.c:576
576     relocate_doit (void *a)
Current language:  auto; currently c
(gdb) sig 2
Continuing with signal SIGINT.
errno=514

Program exited normally.
(gdb) 

[crsd@doughnuthole gdberr]$ ldd gdberr 
        libpthread.so.0 => /lib/tls/libpthread.so.0 (0x00675000)
        libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00799000)
        libm.so.6 => /lib/tls/libm.so.6 (0x0063e000)
        libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x0077f000)
        libc.so.6 => /lib/tls/libc.so.6 (0x0050b000)
        /lib/ld-linux.so.2 (0x009ae000)
[crsd@doughnuthole gdberr]$ ls -l /lib/tls/libpthread*
-rwxr-xr-x  1 root root 107952 Aug 12  2006 /lib/tls/libpthread-2.3.4.so
lrwxrwxrwx  1 root root     19 Mar 24 21:21 /lib/tls/libpthread.so.0 -> libpthread-2.3.4.so
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:
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