(2013/12/24 15:39), Jovi Zhangwei wrote: > On Mon, Dec 23, 2013 at 6:59 PM, Masami Hiramatsu > <masami.hiramatsu.pt@xxxxxxxxxxx> wrote: >> (2013/12/23 13:51), Jovi Zhangwei wrote: >>> On Fri, Dec 20, 2013 at 5:21 PM, Masami Hiramatsu >>> <masami.hiramatsu.pt@xxxxxxxxxxx> wrote: >>>> (2013/12/20 17:31), Jovi Zhangwei wrote: >>>>> On Fri, Dec 20, 2013 at 12:42 PM, Masami Hiramatsu >>>>> <masami.hiramatsu.pt@xxxxxxxxxxx> wrote: >>>>>> (2013/12/20 12:07), Jovi Zhangwei wrote: >>>>>>> On Fri, Dec 20, 2013 at 10:37 AM, Masami Hiramatsu >>>>>>> <masami.hiramatsu.pt@xxxxxxxxxxx> wrote: >>>>>>>> Hi Jovi, >>>>>>>> >>>>>>>> (2013/12/19 18:37), Jovi Zhangwei wrote: >>>>>>>>> Hi Masami, >>>>>>>>> >>>>>>>>> On Thu, Dec 19, 2013 at 5:04 PM, Masami Hiramatsu >>>>>>>>> <masami.hiramatsu.pt@xxxxxxxxxxx> wrote: >>>>>>>>>> memcpy/memset functions are fundamental functions and >>>>>>>>>> those are involved in kprobe's exception handling. >>>>>>>>>> Prohibit probing on them to avoid kernel crash. >>>>>>>>>> >>>>>>>>> Would you please let me know the LKML link of that bugfix, I cannot >>>>>>>>> find it in my LKML fold. >>>>>>>> >>>>>>>> Yeah, that was found in my testing environment. >>>>>>>> >>>>>>>>> No objection on this patch. :) just want to know more, It seems there >>>>>>>>> have no problem to probe memcpy in my box, maybe I didn't hit the >>>>>>>>> crash code path. >>>>>>>> >>>>>>>> Ah, I see. Originally the problem happened when I put a probe on >>>>>>>> __memcpy. And it looks the instances of memcpy and __memcpy are >>>>>>>> same on x86-64. Thus I decided to blacklist both. (memset/__memset too) >>>>>>>> Have you ever tried to probe __memcpy on your box? >>>>>>>> >>>>>>> Hmm, still no crash, __memcpy and __memset are both tested. >>>>>>> >>>>>>> I use below kprobe related config: >>>>>>> >>>>>>> CONFIG_KPROBES=y >>>>>>> CONFIG_JUMP_LABEL=y >>>>>>> CONFIG_OPTPROBES=y >>>>>>> CONFIG_KPROBES_ON_FTRACE=y >>>>>> >>>>>> Hmm, I've added some debugging options. >>>>>> >>>>>> CONFIG_SLUB_DEBUG=y >>>>>> CONFIG_X86_DEBUGCTLMSR=y >>>>>> CONFIG_PNP_DEBUG_MESSAGES=y >>>>>> CONFIG_DEBUG_INFO=y >>>>>> CONFIG_DEBUG_FS=y >>>>>> CONFIG_DEBUG_KERNEL=y >>>>>> CONFIG_DEBUG_STACK_USAGE=y >>>>>> CONFIG_DEBUG_MEMORY_INIT=y >>>>>> CONFIG_DEBUG_STACKOVERFLOW=y >>>>>> CONFIG_DEBUG_SPINLOCK=y >>>>>> CONFIG_DEBUG_MUTEXES=y >>>>>> CONFIG_DEBUG_LOCK_ALLOC=y >>>>>> CONFIG_DEBUG_LOCKDEP=y >>>>>> CONFIG_DEBUG_BUGVERBOSE=y >>>>>> CONFIG_DEBUG_RODATA=y >>>>>> CONFIG_DEBUG_BOOT_PARAMS=y >>>>>> >>>>>> I guess some of them might cause it. >>>>>> >>>>> I recompiled the kernel with those config enabled, unfortunately still no crash, >>>>> I tested on 3.13.0-rc4, a fedora kvm box. >>>> >>>> Hmm, it's very odd. I'm running 3.13.0-rc4 x86-64 on the fedora >>>> kvm box too. here is the full of my kconfig. >>>> >>> That configuration is still working for me, no crash for memcpy kprobe test. >> >> Would you do __memcpy test? or memcpy test? I only had a crash on the >> __memcpy(__memset). >> > Still no crash, use your kernel config. > memcpy and __memcpy have same address in /proc/kallsyms. > > Looks like a interesting problem. Agreed. In my case, those have same address, but only probing __memcpy caused a kernel crash. I'm not sure why, but it is safe to disable probing on it. Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@xxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
