> > On Wed, 5 Jun 2002 13:23:12 -0500, > Robin Holt <[EMAIL PROTECTED]> wrote: > >Dean Roe and I were discussing kdb. We both wondered if there was any way > >of getting the .c line numbers from within kdb or some other util > >(objdump). This would greatly increase our use of kdb. > > Reply copied to kdb list. > > To get line numbers you have to compile the kernel with -g and use > objdump. You will have to exit kdb or put the kernel image and source > on a different machine from the one you are debugging in order to run > objdump. Given a failing function, identify the object it lives in. > Example: xlog_state_do_callback which is in fs/xfs/xfs_log.o > > cd linux > rm fs/xfs/xfs_log.o > make CFLAGS_xfs_log.o=-g vmlinux > s=$(sed -ne '/xlog_state_do_callback/s/ .*//p' System.map | tr '[a-z]' '[A-Z]') > e=$(echo -e "obase=16\nibase=16\n$s+500" | bc) > objdump -S --start-address=0x$s --stop-address=0x$e vmlinux
Any idea how to get this to work with kernel modules? I haven't been able to get any source intermixed with the instructions of any kernel modules (built with -g of course). > >On a different note, we notice that occasionally the 'bt' gives us either > >truncated or repeating results. We were wondering if you had seen this > >behavior or should we open a bug with more details. > > > If it is ia64 then the backtrace should be clean, ia64 has a well > defined ABI for unwinding the call trace. However if the error > occurred in code without unwind data (PAL or SAL do not have unwind > data) or with incorrect unwind then you are SOL. IA64 return registers > are not held in the data stack, they are held in the register stack > which starts at the bottom of the stack pages and grows upwards. Get > the value of rds from regs, subtract 0x200 and mds from that value, > looking for return addresses. So if we do have unwind data and things look pretty normal, we should start filing bugs then? It seems we are able to get truncated and/or looping stack traces somewhat frequently on both dig and sn2 machines. Thanks, Dean --- Dean Roe Silicon Graphics, Inc. [EMAIL PROTECTED] (651) 683-5203
