On 01/26/2012 12:03 AM, Mayank Kaushik wrote: > Hi, > > (Apologies if this is a repost. I sent an earlier, similar mail to > this list but I think it got dropped.) > > I'm trying to setup kernel debugging for my Pandaboard, which has a TI > OMAP4460 (ARMv7 ISA/ dual-core Cortex A9). > I'm able to do an "echo g > /proc/sysrq-trigger" and have gdb connect > to the�target board over a USB to serial cable, view backtraces, set > and stop at breakpoints; but as soon as I try to single step, the > session hangs. > Even nexti, stepi etc hang. I'm able to do a "finish" though. > > The target is running Ubuntu, kernel 2.6.38-1209-omap4: > Linux 2.6.38-1209-omap4 #16 SMP PREEMPT Sat Nov 5 15:53:03 CDT 2011 > armv7l armv7l armv7l GNU/Linux > > The gdb-version I'm using from the host is 7.3.1, I compiled with > support for arm-elf targets: > > $ sudo ./arm-gdb ./vmlinux-arm > GNU gdb (GDB) 7.3.1 > This GDB was configured as "--host=x86_64-unknown-linux-gnu --target=arm-elf". > > Connecting to the target: > (gdb) bt > #0 �kgdb_breakpoint () at /sources/ubuntu-natty/kernel/debug/debug_core.c:959 > #1 �0xc0325ce4 in __handle_sysrq (key=0x67, check_mask=<optimized > out>) at /sources/ubuntu-natty/drivers/tty/sysrq.c:522 > #2 �0xc0325db4 in write_sysrq_trigger (file=<optimized out>, > buf=<optimized out>, count=0x2, ppos=<optimized out>) at > /sources/ubuntu-natty/drivers/tty/sysrq.c:870 > (...) > > I turned on "set debug remote 1" just before issuing a single-step > command, and here's the spew: > > (gdb) set debug remote 1 > (gdb) n > 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: > (...session hangs...) > > At this point I am able to hit Ctrl-C, and attach to the target again. > The target is still at the same instruction as before when I > re-attach. > Does linux/KGDB have trouble with single stepping this target? > > Any help would be appreciated.
My experience is that single-stepping doesn't work on ARM in KDB. I'm not sure if KGDB is uses the same single-stepping infrastructure as KDB or not. If so, it's completely non-functional from what I can tell. -- Tim ============================= Tim Bird Architecture Group Chair, CE Workgroup of the Linux Foundation Senior Staff Engineer, Sony Network Entertainment ============================= ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Kgdb-bugreport mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport
