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 -- 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
