I think the problems were in the way the line information was structured in the kernel module ELF. The line information of all the objects were clubbed together when compiling for x86_64 but the starting numbers were not taken into account. This how the line no.s in the resulting ko ELF objects looks like for x84_64: addr line file 0x1 1 super.c 0x2 2 super.c 0x3 3 super.c 0x1 4 balloc.c 0x2 5 balloc.c As you can see, from balloc.c onwards, the addresses are reset to 1 (instead of 0x4). On the other hand I've compiled for different architectures like (UML) and the resulting ko have continugous addresses across different .o : 0x1 1 super.c 0x2 2 super.c 0x3 3 super.c 0x4 4 balloc.c 0x5 5 balloc.c Looks like gdb 6.8 gets confused when the addresses are reset, but gdb 7.0 doesn't. Further, gdb 6.8 works and can interpret line numbers properly when compiling kernel modules for different architectures (other than x86_64) so the problem is in the way line number debug info is structured in the ko and not in gdb. Thanks, -Joel On Wed, Jan 27, 2010 at 5:23 AM, Peter Teoh <htmldeveloper@xxxxxxxxx> wrote: > this is interesting....i learning something new again... > > pardon me if i may disagree :-). > > i don't think it is a bug for gdb6.8 - it is a very simple > feature....and gdb6.8 must have got right....some point in time in the > past --> for a particular version of gcc in the past (which create the > debuginfo). but when u move forward your gcc version, and gdb lacks > behind too far.....there will be a mismatch problem.....developer > cannot possibly test so many version combination....well this is > controversial....i may be wrong..... > > On Fri, Jan 22, 2010 at 10:04 PM, Mulyadi Santosa > <mulyadi.santosa@xxxxxxxxx> wrote: >> On Fri, Jan 22, 2010 at 12:20 PM, Joel Fernandes <agnel.joel@xxxxxxxxx> wrote: >>> Incase it helps some one else, I upgraded from gdb-6.8 to gdb 7.0 and >>> the line numbers show up fine. >> >> hmffffff, bug in DWARF reading.... >> >> -- >> regards, >> >> Mulyadi Santosa >> Freelance Linux trainer and consultant >> >> blog: the-hydra.blogspot.com >> training: mulyaditraining.blogspot.com >> >> -- >> To unsubscribe from this list: send an email with >> "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx >> Please read the FAQ at http://kernelnewbies.org/FAQ >> >> > > > > -- > Regards, > Peter Teoh > -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
