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Date: Mon, 03 Dec 2007 20:14:09 -0800
From: Julian Elischer <julian@elischer.org>
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Subject: remote gdb failures in recent builds (last 6 months or so.)
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Here's a trace of kgdb attempting to sync with a kernel over the serial 
port..

--->    "+"

--->    "$Hc-1#09"

   <--- "$T058:e3375ac0;thread:186c5;#b5$T058:e3375ac0;thread:186c5;#b5"

--->    "$Hc-1#09"

   <--- "$T058:e3375ac0;thread:186c5;#b5$T058:e3375ac0;thread:186c5;#b5"

--->    "$Hc-1#09"

   <--- "$T058:e3375ac0;thread:186c5;#b5$T058:e3375ac0;thread:186c5;#b5"

--->    "$Hc-1#09"

   <--- "$T058:e3375ac0;thread:186c5;#b5$T058:e3375ac0;thread:186c5;#b5"

--->    "-"

   <--- "$T058:e3375ac0;thread:186c5;#b5$"

--->    "+"

--->    "$qC#b4"

   <--- "T058:e3375ac0;thread:186c5;#b5$T058:e3375ac0;thread:186c5;#b5"

--->    "$qC#b4"

   <--- "$T058:e3375ac0;thread:186c5;#b5$T058:e3375ac0;thread:186c5;#b5"

--->    "$qC#b4"

   <--- "$T058:e3375ac0;thread:186c5;#b5$T058:e3375ac0;thread:186c5;#b5"

--->    "$qC#b4"

   <--- "$T058:e3375ac0;thread:186c5;#b5$T058:e3375ac0;thread:186c5;#b5"

--->    "-"

   <--- "$T058:e3375ac0;thread:186c5;#b5$"

--->    "+"

--->    "$qOffsets#4b"

   <--- "T058:e3375ac0;thread:186c5;#b5$T058:e3375ac0;thread:186c5;#b5"

--->    "$qOffsets#4b"

   <--- "$T058:e3375ac0;thread:186c5;#b5$T058:e3375ac0;thread:186c5;#b5"

--->    "$qOffsets#4b"

   <--- "$T058:e3375ac0;thread:186c5;#b5$T058:e3375ac0;thread:186c5;#b5"

--->    "$qOffsets#4b"

--->    "-"

   <--- "$T058:e3375ac0;thread:186c5;#b5$"

--->    "+"

"Couldn't establish connection to remote target 

"

"Malformed response to offset query, T058:e3375ac0;thread:186c5;"

note that:
1/ gdb CAN read the damned data.. this is obtained from ktrace.
2/ it prints out the packet in the error message.
3/ teh kernel is sending each message twice, in pairs.
4/ after kgdb finally sends a '-' (NAK) teh kernel sends ONE MORE
which seems to be accepted

Anyone have any clues?




~