On Thu, 2014-02-27 at 03:45 +0000, Ken Moffat wrote: > On Thu, Feb 27, 2014 at 04:26:35AM +0100, Mike Galbraith wrote: > > > > I would start with strace to see if a task is looping in userspace, then > > move on to perf top -g -p <pid> (or perf record/report) to peek at what > > it's up to in the kernel. Once you have the where, trace_printk() is > > the best thing since sliced bread (which ranks just below printk()). > > > > -Mike > Thanks. I'll need to build perf.
You may want to build the kernel with frame-pointers too, for easy gdb list *0x(hexnum) of *func()+0x(hexoffset) use. Crash is also pretty handy both for rummaging live via crash vmlinux /proc/kcore, and for leisurely postmortem analysis if you set the box up to crashdump in advance, and force a dump (poke sysrq-c or echo c > /proc/sysrq-trigger) when you see the bad thing happen. Crash has all kinds of goodies, including invocation of gdb. -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
