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Re: kgdb on arm for 2.6: msg#00111
linux.kernel.debugging.kgdb.bugs
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Subject: |
Re: kgdb on arm for 2.6 |
Lance Spaulding wrote:
George Anzinger wrote:
There is something very wrong here. The old code did not even attempt
a $s command where as the new kgdb did get a $s. I suspect that there
is history that we need to know to understand this. Could you try
this again with set debug remote 1 on from the start (put it in you
.gdbinit file). Then make the first command the "si".
I assume you are using the same gdb for each of these. Right?
George
Hi George,
You are right that I was using different versions of gdb for the two
traces as I use different toolchains to compile 2.4 vs 2.6. The 2.4
trace was using gdb 6.0 while the 2.6 trace was using gdb 6.1. After
your email, I tried single-stepping on both 2.4 and 2.6 using both gdb
6.0 and 6.1. Gdb 6.0 works fine on both platforms but gdb 6.1 only
single-steps correctly using the old kgdb and 2.4. The following shows
the full trace of an attempted step on both 2.4 and 2.6 using gdb 6.1.
In both cases, I compiled in a call to breakpoint() and then connected
gdb and simply ran 'si'.
Hm... Looks like a gdb bug then. The trace you did not show is the 6.0 gdb
on the 2.6 kgdb. That would be most interesting. What I am seeing below is
the 2.4 kgdb is doing the full single step on its own. What I would expect
to see the 6.0 gdb on the 2.6 kgdb doing is fetching the instruction, doing
what ever side effects the instruction generates such as changing the PC and
registers and, possibly memory.
George
--
Here's the successful single-step on 2.4 w/ gdb 6.1:
GNU DDD 3.3.11 (i686-pc-linux-gnu), by Dorothea Lütkehaus and Andreas
Zeller.
Copyright © 1995-1999 Technische Universität Braunschweig, Germany.
Copyright © 1999-2001 Universität Passau, Germany.
Copyright © 2001 Universität des Saarlandes, Germany.
Copyright © 2001-2004 Free Software Foundation, Inc.
(gdb) target remote lcsdebug6:4013
Sending packet: $Hc-1#09...Ack
Packet received: OK
Sending packet: $qC#b4...Ack
Packet received:
Sending packet: $qOffsets#4b...Ack
Packet received:
Sending packet: $?#3f...Ack
Packet received: S05
Sending packet: $Hg0#df...Ack
Packet received: OK
Sending packet: $g#67...Ack
Packet received:
13000000044005f0010000000000000000000000a4760a0160760a010501000001ff00ff000000000000000080baff1f1300000074baff1f130000002c3101000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000013000060
0x0001312c in breakpoint () at kgdb-stub.c:1123
in kgdb-stub.c
(gdb) si
Sending packet: $m130fc,4#2a...Ack
Packet received: 0dc0a0e1
Sending packet: $m13100,4#c2...Ack
Packet received: 00d82de9
Sending packet: $m13104,4#c6...Ack
Packet received: 24209fe5
Sending packet: $m13108,4#ca...Ack
Packet received: 003092e5
Sending packet: $m1310c,4#f5...Ack
Packet received: 04b04ce2
Sending packet: $m13110,4#c3...Ack
Packet received: 000053e3
Sending packet: $m13114,4#c7...Ack
Packet received: 0130a003
Sending packet: $vCont?#49...Ack
Packet received:
Packet vCont (verbose-resume) is NOT supported
Sending packet: $Hc0#db...Ack
Packet received: OK
Sending packet: $s#73...Ack
Packet received: OK
Packet received: S05
Sending packet: $g#67...Ack
Packet received:
13000000044005f0010000000000000000000000a4760a0160760a010501000001ff00ff000000000000000014bbff1f1300000084baff1f130000000ca604000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000013000060
Sending packet: $m49c30,4#00...Ack
Packet received: 0dc0a0e1
Sending packet: $m49c34,4#04...Ack
Packet received: f0df2de9
Sending packet: $m49c38,4#08...Ack
Packet received: 04b04ce2
Sending packet: $m49c3c,4#33...Ack
Packet received: 0090a0e1
Sending packet: $m49c40,4#01...Ack
Packet received: 68d04de2
Sending packet: $m49c44,4#05...Ack
Packet received: 0c4099e5
Sending packet: $m49c48,4#09...Ack
Packet received: 0000a0e3
Sending packet: $m49c4c,4#34...Ack
Packet received: 3c000be5
Sending packet: $m49c50,4#02...Ack
Packet received: 18e099e5
Sending packet: $m49c54,4#06...Ack
Packet received: 34100be5
Sending packet: $m49c58,4#0a...Ack
Packet received: ffcc04e2
Sending packet: $m49c5c,4#35...Ack
Packet received: 0cc4a0e1
Sending packet: $m49c60,4#03...Ack
Packet received: 04cc8ce1
Sending packet: $m49c64,4#07...Ack
Packet received: ff0804e2
Sending packet: $m49c68,4#0b...Ack
Packet received: 20c48ce1
Sending packet: $m49c6c,4#36...Ack
Packet received: 244c8ce1
Sending packet: $m1fffbae0,4#88...Ack
Packet received: 94bdff1f
Sending packet: $m1fffbadc,4#ba...Ack
Packet received: 00000000
load_flat_file (bprm=0x0, libinfo=0x1fffbd94, id=0, extra_stack=0x1) at
binfmt_flat.c:773
in binfmt_flat.c
(gdb)
Here's the attempted single-step on 2.6 using gdb 6.1:
GNU DDD 3.3.11 (i686-pc-linux-gnu), by Dorothea Lütkehaus and Andreas
Zeller.
Copyright © 1995-1999 Technische Universität Braunschweig, Germany.
Copyright © 1999-2001 Universität Passau, Germany.
Copyright © 2001 Universität des Saarlandes, Germany.
Copyright © 2001-2004 Free Software Foundation, Inc.
(gdb) target remote lcsdebug6:4013
Sending packet: $Hc-1#09...Ack
Packet received: OK
Sending packet: $qC#b4...Ack
Packet received: QC0000000000000001
Sending packet: $qOffsets#4b...Ack
Packet received:
Sending packet: $?#3f...Ack
Packet received: S05
Sending packet: $Hg1#e0...Ack
Packet received: OK
Sending packet: $g#67...Ack
Packet received:
20f1d01f20f1d01f0100000024631e00cc631e000301000001000000010000000000d01f040000003c100000503ea400543ea400403ea40000400800b051040000000000000000000000000000000000000000000000000000000000000000000000000013000060
0x000451b0 in $d () at kernel/kgdb.c:1795
/home/lance/cpb/arm/os/linux-2.6.x/kernel/kgdb.c:1795:47442:beg:0x451b0
(gdb) si
Sending packet: $vCont?#49...Ack
Packet received:
Packet vCont (verbose-resume) is NOT supported
Sending packet: $Hc0#db...Ack
Packet received: OK
Sending packet: $s#73...Ack
Packet received:
warning: Invalid remote reply:
For reference, here the output from gdb --version for both versions:
GNU gdb 6.0
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 "--host=i686-pc-linux-gnu --target=arm-linux".
and
GNU gdb 6.1
Copyright 2004 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 "--host=i686-pc-linux-gnu --target=arm-uclinux".
The 6.1 version that isn't working correctly with the new kgdb came from
uclinux.org. For now, I'll try to use 6.0 to debug with.
Thanks again,
Lance
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--
George Anzinger george@xxxxxxxxxx
HRT (High-res-timers): http://sourceforge.net/projects/high-res-timers/
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