gdb/2054: can't start X server under gdb

Daniel Jacobowitz drow@false.org
Tue Dec 20 00:18:00 GMT 2005


The following reply was made to PR gdb/2054; it has been noted by GNATS.

From: Daniel Jacobowitz <drow@false.org>
To: Adam Jackson <ajackson@redhat.com>
Cc: gdb-gnats@sources.redhat.com
Subject: Re: gdb/2054: can't start X server under gdb
Date: Mon, 19 Dec 2005 19:12:24 -0500

 On Mon, Dec 19, 2005 at 06:59:13PM -0500, Adam Jackson wrote:
 > 
 > On Dec 19, 2005, at 5:05 PM, Daniel Jacobowitz wrote:
 > 
 > >Huh - that (0x4057f) is SIGTRAP | (PTRACE_EVENT_EXEC << 16).  GDB  
 > >shouldn't
 > >be receiving PTRACE_EVENT_EXEC notification.  Is this an unmodified
 > >kernel.org kernel?  Did X exec?
 > 
 > Yes, totally stock kernel.  X does exec xkbcomp(1) as part of startup,  
 > and in fact that's where this is failing (bt after the internal-error):
 > 
 > (gdb) bt
 > #0  0xffffe410 in __kernel_vsyscall ()
 > #1  0xb7e01aa6 in __libc_fork () at fork.c:127
 > #2  0x081affdf in Popen (
 >     command=0x8218370 "\"/opt/debrix/bin/xkbcomp\" -w 1  
 > \"-R/opt/debrix/share/X11/xkb\" -xkm \"-\" -em1 \"The XKEYBOARD keymap  
 > compiler (xkbcomp) reports:\" -emp \"> \" -eml \"Errors from xkbcomp  
 > are not fatal to the X server\" \"/opt/d"..., type=0x81be16f "w") at  
 > utils.c:1766
 > #3  0x08191b2d in XkbDDXCompileKeymapByNames (xkb=0x78,  
 > names=0xb7a36980,
 >     want=120, need=120, nameRtrn=0xbf8a3d40 "T=\212?|=\212??\001",
 >     nameRtrnLen=4096) at ddxLoad.c:379
 > ...
 > 
 > maybe a bad glibc?
 
 We're in __libc_fork.  We've, presumably, just forked.  Your kernel has
 somehow reported event 4, when it ought to have reported event 1
 (fork).
 
 I don't have the faintest idea how this could happen.  It's possible
 the event is somehow coming from the forked child; could you please
 strace gdb for me?  That'll show more clearly what processes we're
 tracing.
 
 -- 
 Daniel Jacobowitz
 CodeSourcery, LLC



More information about the Gdb-prs mailing list