Re: threads/1154: gdb-5.3 + glibc-2.3.2 fail for my multithreaded program

[Daniel Jacobowitz <drow at mvista dot com>]

The following reply was made to PR threads/1154; it has been noted by GNATS.

From: Daniel Jacobowitz <drow at mvista dot com>
To: Mat Hostetter <mat at curl dot com>
Cc: gdb-gnats at sources dot redhat dot com
Subject: Re: threads/1154: gdb-5.3 + glibc-2.3.2 fail for my multithreaded program
Date: Thu, 27 Mar 2003 11:28:47 -0500

 On Thu, Mar 27, 2003 at 11:23:53AM -0500, Mat Hostetter wrote:
 > FWIW this is still broken in gdb-20030327.
 > 
 > If I change selected_frame to get_selected_frame() as you suggest, it
 > does indeed fix the segfault:
 
 Thanks for checking.
 
 > GNU gdb 20030327
 > Copyright 2003 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"...
 > (gdb) handle SIG32 noprint
 > Signal        Stop	Print	Pass to program	Description
 > SIG32         No	No	Yes		Real-time event 32
 > (gdb) run -s
 > Starting program: /local/scratch/mat/trunk/bin/curl-builder -s
 > Couldn't get registers: Operation not permitted.
 > (gdb) info threads
 > Couldn't get registers: Operation not permitted.
 > (gdb) info threads
 > Couldn't get registers: Operation not permitted.
 > (gdb) quit
 > The program is running.  Exit anyway? (y or n) y
 > [hangs forever]
 > 
 > 
 > Trying to quit gdb after the EPERM still hangs forever.
 > Here is the backtrace where it's hung:
 > 
 > (gdb) bt 10
 > #0  0x400fd138 in wait () from /lib/libc.so.6
 
 This does suggest to me that you've ended up with NPTL.
 
 I know why the wait is hanging; I have been discussing a kernel
 behavior change to fix this but I haven't gotten around to finding out
 who in Red Hat is working on their NPTL debug support, and I don't want
 to break whatever they're doing.
 
 > #1  0x08105adc in ptrace_wait (ptid={pid = 0, lwp = 0, tid = 0}, status=0xffffffff) at infptrace.c:206
 > #2  0x08105b53 in kill_inferior () at infptrace.c:229
 > #3  0x080f5196 in quit_force (args=0x0, from_tty=1) at top.c:1715
 > #4  0x08078626 in do_cfunc (c=0xfffffe00, args=0x0, from_tty=1) at cli/cli-decode.c:53
 > #5  0x08079ef6 in cmd_func (cmd=0x82648e8, args=0x0, from_tty=1) at cli/cli-decode.c:1531
 > #6  0x080f3dfe in execute_command (p=0x823fbfc "", from_tty=1) at top.c:711
 > #7  0x080baf01 in command_handler (command=0x823fbf8 "quit") at event-top.c:502
 > #8  0x080bb320 in command_line_handler (rl=0x829a930 " ?)\b") at event-top.c:797#9  0x08191f45 in rl_callback_read_char () at callback.c:123
 > 
 > -Mat
 > 
 
 -- 
 Daniel Jacobowitz
 MontaVista Software                         Debian GNU/Linux Developer