On Wed, Jul 20, 2022 at 11:47:02PM +0200, Peter Zijlstra wrote: > On Wed, Jul 20, 2022 at 12:57:26PM -0500, Justin Forbes wrote: > > On Wed, Jul 20, 2022 at 10:28:33AM -0700, Linus Torvalds wrote: > > > [ Adding PeterZ and Jiri to the participants. ] > > > > > > Looks like 5.18.13 added that commit 9bb2ec608a20 ("objtool: Update > > > Retpoline validation") but I don't see 3131ef39fb03 ("x86/asm/32: Fix > > > ANNOTATE_UNRET_SAFE use on 32-bit") in that list. > > > > It should be noted that the build doesn't fail, it just warns. > > I am guessing the 32bit failure is what promoted someone to look at > > the logs to begin with and notice the warn initially. I just verified > > that it exists in our builds of 5.18.13-rc1, but not on mainline builds. > > I am gueesing it is because commit 9bb2ec608a20 ("objtool: Update Retpoline > > validation") should be followed up with at least commit f43b9876e857c > > ("x86/retbleed: Add fine grained Kconfig knobs") > > Still updateing the stable repro to see what the actual code looks like, > but that warning seems to suggest the -mfunction-return=thunk-extern > compiler argument went missing. > > For all the files objtool complains about, does the V=1 build output > show that option? Ok, I'm now looking at stable-rc/linux-5.18.y which reports itself as: VERSION = 5 PATCHLEVEL = 18 SUBLEVEL = 13 EXTRAVERSION = -rc1 and I'm most terribly confused... it has the objtool patch to validate return thunks, *however*, I'm not seeing any actual retbleed mitigations *anywhere*. How, what, why!?