[Kgdb-bugreport] KGDB problem at first breakpoint

Tue May 31 04:51:27 EDT 2011

No luck. Atleast, I am interested to know, if it is working for anyone or
there is a bug in kgdb implementation in the kernel. If so, I can cool off
for some more days until it gets rectified.

Thanks,
Prabhu

On Fri, May 27, 2011 at 10:06 PM, Dongdong Deng <libfetion at gmail.com> wrote:

> On Fri, May 20, 2011 at 12:23 PM, Prabhu nath <gprabhunath at gmail.com>
> wrote:
> > Enabling CONFIG_DEBUG_RODATA also didn't work.
>
>
> I am sorry, the CONFIG_DEBUG_RODATA should be disabled...
>
>
> Could you try to pass full parameters to kgdboc module?
> "kgdboc=ttyS0,115200 kgdbwait"
>
>
> Dongdong
>
>
>
> >
> > -Prabhu
> >
> >
> > On Thu, May 19, 2011 at 6:45 AM, Dongdong Deng <libfetion at gmail.com>
> wrote:
> >>
> >> On Wed, May 18, 2011 at 7:23 PM, Prabhu nath <gprabhunath at gmail.com>
> >> wrote:
> >> > Dear All,
> >> >
> >> >       There is a problem with the KGDB at the very first break point
> >> > after
> >> > executing the gdb command "target remote /dev/ttyS0" from the host.
> >> >       I have verbatim, followed the KGDB document
> >> > http://kernel.org/pub/linux/kernel/people/jwessel/kdb/
> >> >
> >> > Problem Logs:
> >> > ---------------------
> >> >
> >> > Details  of my hardware and system software:
> >> > -------------------------------------------------------------------
> >> >
> >> > *Host (Development machine): *
> >> >                      Intel Pentium IV Machine with Fedora Core 12
> >> >                      Linux Version : 2.6.31.5-127.fc12.i686.PAE
> >> >                      gdb version : GNU gdb (GDB) Fedora (7.0-3.fc12)
> >> >
> >> > *Target:*
> >> >                 Intel Pentium IV Machine with Fedora Core 12
> >> >                 Customized Linux Version :  2.6.38
> >> >
> >> > Host is connected to Target via a null modem cable
> >> >
> >> > *Snapshot of .config of linux version 2.6.38 on the target *
> >> > *
> >> > *
> >> > # CONFIG_DEBUG_RODATA is not set
> >>
> >>
> >> Hi Prabhu,
> >>
> >> The CONFIG_DEBUG_RODATA was suggested to set at KGDB,
> >> Could you enable it?
> >>
> >> CONFIG_DEBUG_RODATA = y
> >>
> >> Dongdong
> >>
> >
> >>
> >> >
> >> > CONFIG_HAVE_ARCH_KGDB=y
> >> > CONFIG_FRAME_POINTER=y
> >> > CONFIG_DEBUG_INFO=y
> >> > CONFIG_KGDB=y
> >> > CONFIG_KGDB_SERIAL_CONSOLE=y
> >> > CONFIG_KGDB_LOW_LEVEL_TRAP=y
> >> >
> >> > *Grub config on the target machine*
> >> > *
> >> > *
> >> > title Fedora (2.6.38)
> >> >        root (hd0,0)
> >> >        kernel /boot/vmlinuz-2.6.38 ro
> >> > root=UUID=fb7800fb-cfe7-438d-bc7f-c153ba4353d1  LANG=en_US.UTF-8
> >> > SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc
> >> > KEYTABLE=us*console=ttyS0,115200n8
> >> > kgdboc=ttyS0 kgdbwai*t
> >> >        initrd /boot/initrd-2.6.38.img
> >> >
> >> >
> >> > On power on of the target, linux kernel boots and the logs are seen on
> >> > the
> >> > minicom console of the host and it will wait for the gdb on the host
> to
> >> > connect. Here is the last 4 lines of the logs seen on the minicom
> >> >
> >> > Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
> >> > serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
> >> > 00:06: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
> >> > kgdb: Registered I/O driver kgdboc.
> >> > kgdb: Waiting for connection from remote gdb..
> >> >
> >> > *--- Now I close the minicom console (Ctrl-A X) and start the gdb on
> the
> >> > host. Here is the steps I follow. *
> >> > *
> >> > *
> >> > *On the host machine:*
> >> > *
> >> > *
> >> >
> >> > [root at localhost kgdb]# gdb vmlinux
> >> >
> >> > GNU gdb (GDB) Fedora (7.0-3.fc12)
> >> > Copyright (C) 2009 Free Software Foundation, Inc.
> >> > License GPLv3+: GNU GPL version 3 or later
> >> > <http://gnu.org/licenses/gpl.html
> >> >>
> >> > This is free software: you are free to change and redistribute it.
> >> > There is NO WARRANTY, to the extent permitted by law.  Type "show
> >> > copying"
> >> > and "show warranty" for details.
> >> > This GDB was configured as "i686-redhat-linux-gnu".
> >> > For bug reporting instructions, please see:
> >> > <http://www.gnu.org/software/gdb/bugs/>...
> >> > Reading symbols from /root/kgdb/vmlinux...done.
> >> >
> >> > (gdb) set remotebaud 115200
> >> > (gdb) set debug remote 1
> >> > (gdb) target remote /dev/ttyS0
> >> > Remote debugging using /dev/ttyS0
> >> > Sending packet: $qSupported#37...Ack
> >> > Packet received:
> >> > Packet qSupported (supported-packets) is NOT supported
> >> > Sending packet: $Hg0#df...Ack
> >> > Packet received: OK
> >> > Sending packet: $?#3f...Ack
> >> > Packet received: S05
> >> > Sending packet: $Hc-1#09...Ack
> >> > Packet received: OK
> >> > Sending packet: $qC#b4...Ack
> >> > Packet received: QC01
> >> > Sending packet: $qAttached#8f...Ack
> >> > Packet received:
> >> > Packet qAttached (query-attached) is NOT supported
> >> > Sending packet: $qOffsets#4b...Ack
> >> > Packet received:
> >> > Sending packet: $g#67...Ack
> >> > Packet received:
> >> >
> >> >
> 36000000ffffffff0abaffff20d98bc06c3f86de783f86de803ac8dd803f86de885747c00202000060000000680000007b00c8dd7b0086deffff0000ffff0000
> >> > Sending packet: $mc0475788,1#a4...Ack
> >> > Packet received: 0f
> >> > Sending packet: $mc0475788,8#ab...Ack
> >> > Packet received: 0faef889f6ff0d08
> >> > Sending packet: $mc0475788,7#aa...Ack
> >> > Packet received: 0faef889f6ff0d
> >> > 0xc0475788 in ?? ()
> >> > Sending packet: $qSymbol::#5b...Ack
> >> > Packet received:
> >> > Packet qSymbol (symbol-lookup) is NOT supported
> >> > (gdb) s
> >> > Cannot find bounds of current function
> >> > (gdb)
> >> >
> >> >
> >> > *Observation:*
> >> >                     *1.* Ideally the kernel being debugged should
> break
> >> > at
> >> > legitimate address and the corresponding line number should
> >> >                         be displayed instead of " 0xc0475788 in ??
> ()".
> >> >
> >> >                     2. On inspecting section header in vmlinux
> >> > executable,
> >> > I found the .text section address range is from
> >> >                         0xC1000000 to 0xC1326e58  and no section's
> >> > contents
> >> > associate with the address 0xC0475788.
> >> >
> >> >                     *3.* Hence on single stepping, gdb logs the error
> >> > as* "Cannot
> >> > find bounds of current function"*
> >> > *
> >> > *
> >> >  Humbly request you to help me in addressing this issue.
> >> >
> >> > Thanks and Regards,
> >> > Prabhu
> >> >
> >> >
> ------------------------------------------------------------------------------
> >> > What Every C/C++ and Fortran developer Should Know!
> >> > Read this article and learn how Intel has extended the reach of its
> >> > next-generation tools to help Windows* and Linux* C/C++ and Fortran
> >> > developers boost performance applications - including clusters.
> >> > http://p.sf.net/sfu/intel-dev2devmay
> >> > _______________________________________________
> >> > Kgdb-bugreport mailing list
> >> > Kgdb-bugreport at lists.sourceforge.net
> >> > https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport
> >> >
> >
> >
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20110531/4beec230/attachment-0001.html 