On Wed, May 18, 2011 at 12:23 PM, Prabhu nath <gprabhunath@xxxxxxxxx> 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 > 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=usconsole=ttyS0,115200n8 > kgdboc=ttyS0 kgdbwait > initrd /boot/initrd-2.6.38.img Do you have other serial line that you can connect to ? If you have you could try to connect the console or the kgdboc to other serial line. This way you can have each on it's private serial line. I don't know if it can multiplex the signal. > > 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@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 > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies@xxxxxxxxxxxxxxxxx > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > -- Nuno Martins _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
