Am 11.05.2015 um 10:59 schrieb Richard Weinberger: > Am 11.05.2015 um 02:24 schrieb Masami Hiramatsu: >> On 2015/05/11 4:42, Richard Weinberger wrote: >>> While debugging issues I often add (trace_)printks to strategic positions. >>> Dealing with user provided string is complicated as an extra buffer a >>> copy_from_user() is needed. >>> This adds a new format string to allow direct printing of such strings. >>> >>> My initial plan was to use %pU but 'U' is already taken, therefore >>> I used the next letter which comes in mind when one thinks of userpace, >>> 'L'. >>> The %pL format string works exactly like %s. >> >> BTW, if you need to do this for debug, you can also use ftrace's >> kprobe-tracer >> (and perf probe) which allows you to dump userspace strings :) > > Sounds promising! > > But I fail to use it: > $ perf probe -vv -L do_sys_open:0-3 -k > /boot/vmlinux-4.1.0-rc2-3.g3541e77-vanilla > Line range is 0 to 3 > Use vmlinux: /boot/vmlinux-4.1.0-rc2-3.g3541e77-vanilla > Failed to find path of kernel module. > Error: Failed to show lines. Reason: No such file or directory (Code: -2) > > Any idea what's the issue?
Okay, works now as expected. :-) Had the wrong debuginfo package installed. Thanks, //richard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
