Michael, fentry is required (and mcount won't work).
On Wed, Feb 10, 2016 at 01:42:37AM +0000, Michael Liu (zuwliu) wrote: > Hi Josh, > > When I run kpatch-build tool for the memnfo-string.patch on our 3.4 kernel, I > got an error of > > meminfo.o: function meminfo_proc_show has no fentry call, unable to patch > > It seems the fentry support is added in > d57c5d51a30152f3175d2344cb6395f08bf8ee0c, which I didn’t backport yet. Should > I backport it and maybe some other commits? > > Or there is a kpatch version which only use mcount instead of fentry? > > > commit d57c5d51a30152f3175d2344cb6395f08bf8ee0c > Author: Steven Rostedt <[email protected]<mailto:[email protected]>> > Date: Wed Feb 9 13:32:18 2011 -0500 > > ftrace/x86: Add support for -mfentry to x86_64 > > > > Thanks > Michael > > > > > On Jan 27, 2016, at 7:55 PM, Josh Poimboeuf > <[email protected]<mailto:[email protected]>> wrote: > > Michael, > > The 06aeaaeabf69da4a3e86df532425640f51b01cef commit seems to be just a > cosmetic change so I don't think you need it (unless it's a dependency > for another needed change). > > Otherwise I'm not sure what else you need. > > On Wed, Jan 27, 2016 at 04:16:39AM +0000, Michael Liu (zuwliu) wrote: > Hi Josh, > > Wondering to which stage of ftrace I need to backport to 3.4 kernel? I > already back ported commits: > > 08f6fba503111e0336f2b4d6915a4a18f9b60e51 (ftrace/x86: Add separate function > to save regs) > 647664eaf4033501739ac1f42dd52ce8c9266ccc (ftrace: add ftrace_set_filter_ip() > for address based filter) > > Now I can compile kmod/core KLM in kpatch on 3.4 kernel. Wondering do I need > also backport the commit of > > 06aeaaeabf69da4a3e86df532425640f51b01cef (ftrace: Move > ARCH_SUPPORTS_FTRACE_SAVE_REGS in Kconfig) > > to make kpatch really work on 3.4 kernel? > > Really appreciate your help! > > Thanks > Michael > > > > > On Jan 20, 2016, at 7:39 AM, Josh Poimboeuf > <[email protected]<mailto:[email protected]><mailto:[email protected]>> > wrote: > > On Tue, Jan 19, 2016 at 04:15:10PM +0000, Michael Liu (zuwliu) wrote: > I joined the member and try to send it again. > > Hello Kpatch, > > I’m in a project which requires running kpatch on our 3.4 kernel, wondering > how much effort is needed to do so? > > We currently using GCC 4.6.3, but I think we can move to GCC 4.8 if needed. > However we cannot move our kernel to 3.9. > > In 3.4 kernel I saw there is already ftrace, although there is no > CONFIG_DYNAMIC_FTRACE_WITH_REGS feature. Wondering whether > CONFIG_DYNAMIC_FTRACE_WITH_REGS is the only feature missing on 3.4 to support > kpatch? Are there other things we need to backport to run kpatch on 3.4 > kernel? > > Thank you for your time! > > Hi Michael, > > CONFIG_DYNAMIC_FTRACE_WITH_REGS is the biggest required feature I know > about that's missing on 3.4. > > Also, there are at least some minor kernel API differences that affect > the kpatch core module, described here: > > https://github.com/dynup/kpatch/issues/257 > > GCC 4.6 may have issues: > > https://github.com/dynup/kpatch/issues/246#issuecomment-46615292 > > Those are just the problems I know about. You might run into other > issues... > > -- > Josh > > > -- > Josh > -- Josh _______________________________________________ kpatch mailing list [email protected] https://www.redhat.com/mailman/listinfo/kpatch
