On 2015/05/11 19:57, Richard Weinberger wrote: > 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.
Ah, the message is not good... If you give "-vv" (double -v options), you'll see below reason. symsrc__init: build id mismatch for /boot/vmlinux-4.1.0-rc2-3.g3541e77-vanilla I'll fix that. Thank you for reporting! -- Masami HIRAMATSU Linux Technology Research Center, System Productivity Research Dept. Center for Technology Innovation - Systems Engineering Hitachi, Ltd., Research & Development Group E-mail: masami.hiramatsu...@hitachi.com -- 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/
