> On Jul 15, 2015, at 21:24, Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote: > > On Wed, Jul 15, 2015 at 05:02:19PM +0800, Minfei Huang wrote: >> On 07/15/15 at 10:53P, Miroslav Benes wrote: >>> On Tue, 14 Jul 2015, Josh Poimboeuf wrote: >>> >>>> On Tue, Jul 14, 2015 at 10:57:46PM +0200, Jiri Kosina wrote: >>>>> On Tue, 14 Jul 2015, Josh Poimboeuf wrote: >>>>> >>>>>> Here's another issue [1] which Jessica found. It affects the livepatch >>>>>> sysfs API, so we should probably fix it soon before we get actual users. >>>>>> >>>>>> Here's our current sysfs layout for displaying patched function names: >>>>>> >>>>>> /sys/kernel/livepatch/<patch>/<object>/<func> >>>>>> >>>>>> A problem occurs when patching two distinct functions which have the >>>>>> same name: >>>>> >>>>> ... and are both built-in. >>>> >>>> True. >>> >>> I think we even discussed this issue a while ago. Can't find it now in the >>> archives and don't remember the outcome... >>> >>>>>> sysfs: cannot create duplicate filename '/kernel/livepatch/kpatch_s_next_ambig/vmlinux/s_next' >>>>>> >>>>>> Does anybody rely on the "func" sysfs entry? >>>>> >>>>> Well, our sysfs ABI is documented in testing/, so if worse comes to worst, >>>>> we should be able to fix it in a backwards incompatible way without being >>>>> called the bad guys breaking userspace. >>>> >>>> Ok. Hopefully it doesn't come to that :-) >>>> >>>>> >>>>>> I suppose our options are to either remove "func" completely or replace >>>>>> it with something more unique like the function address. >>>>> >>>>> How about extending the attribute to consist of both name and the address. >>>>> That will automatically provide disambiguation, and would still maintain >>>>> human readability. >>>> >>>> Sounds fine to me. Something like: >>>> >>>> "cmdline_proc_show,0xffffffff812904c0" ? >>> >>> Unfortunately this would be shown even to non-root users and is >>> information leak (if kptr_restrict is set to non-zero). >> >> How about append the patched function name in the sysfs. It may be more >> clear to show the relationship between function and patched function. > > But that still doesn't guarantee a unique name if all the functions are > static. > > -- > Josh Hi, Josh. I think this approach can fix this issue, since function name is unique in one module. The func name may be like this livepatch_s_next-s_next which consists of function name livepatch_s_next and patched function name s_next. Thanks Minfei-- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
