Re: gdb/2238: assertion failure in linux_nat_attach() when attachingto a hung Xorg instance

[Bernardo Innocenti <bernie at codewiz dot org>]

The following reply was made to PR gdb/2238; it has been noted by GNATS.

From: Bernardo Innocenti <bernie@codewiz.org>
To: Daniel Jacobowitz <drow@false.org>
Cc: gdb-gnats@sources.redhat.com
Subject: Re: gdb/2238: assertion failure in linux_nat_attach() when attaching
 to a hung Xorg instance
Date: Wed, 07 Mar 2007 18:29:21 +0100

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 Daniel Jacobowitz wrote:
 
 > Do you get the same results if you use an FSF GDB?  I don't know if
 > any of the patches Red Hat applies affect this.
 
 Yes, I've rebuilt from gdb's CVS HEAD, hit the same assertion
 failure, then removed the assertion to see if gdb could run
 anyway (and it did).
 
 
 >> Maybe Xorg also does something weird with signal masks.  This is the stack backtrace I get if I rebuild gdb
 >> without the assertion:
 > 
 > Could you check which bit of the assertion failed, and how so?
 > Probably the wait status is something unusual.
 
 I can't restart the debug session now because the X server
 is now running fine, but I did some tests and I remember
 these facts:
 
   pid == GET_PID (inferior_ptid)
 
 This bit was definitely true
 
   && WIFSTOPPED (status)
 
 This was also true
 
 
   && (WSTOPSIG (status) == SIGSTOP
 
 I think this wasn't true, but I don't know what the signal
 number was in the debug session for which I provided the
 stack trace.
 
 In a different debug session, its value was 29 (SIGIO),
 which the X server actually uses to handle protocol
 requests.
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