On Sat, May 13, 2023 at 12:21:07PM +0200, Borislav Petkov wrote: > On Sat, May 13, 2023 at 05:17:13PM +0900, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > > > > The patch below does not apply to the 5.15-stable tree. > > If someone wants it applied there, or to any other stable or longterm > > tree, then please email the backport, including the original git commit > > id to <stable@xxxxxxxxxxxxxxx>. > > > > To reproduce the conflict and resubmit, you may use the following commands: > > > > git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y > > git checkout FETCH_HEAD > > git cherry-pick -x 9a48d604672220545d209e9996c2a1edbb5637f6 > > # <resolve conflicts, build, test, etc.> > > git commit -s > > git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023051313-wrangle-brick-b43d@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. > > > > Possible dependencies: > > > > 9a48d6046722 ("x86/retbleed: Fix return thunk alignment") > > a149180fbcf3 ("x86: Add magic AMD return-thunk") > > d9e9d2300681 ("x86,objtool: Create .return_sites") > > 15e67227c49a ("x86: Undo return-thunk damage") > > 0b53c374b9ef ("x86/retpoline: Use -mfunction-return") > > 369ae6ffc41a ("x86/retpoline: Cleanup some #ifdefery") > > a883d624aed4 ("x86/cpufeatures: Move RETPOLINE flags to word 11") > > 22922deae13f ("Merge tag 'objtool-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip") > > Right, so that looks like this: > > The patch which causes the misalignment is > > c4691712b546 ("x86/linkage: Add ENDBR to SYM_FUNC_START*()") > > which came in 5.18 (v5.17-rc8-21-gc4691712b546) and the one which adds > the actual untraining sequence: > > a149180fbcf3 ("x86: Add magic AMD return-thunk") > > came in 5.19. > > So adding a Fixes: tag pointing to a patch which goes before the actual > patch didn't make any sense to me last night. > > HOWEVER, Thadeu did backport it here as > > a9c0926fc754 ("x86: Add magic AMD return-thunk") > > but the other patch wasn't backported. > > So the 5.15 build looks good: > > ffffffff81c01f7f <zen_untrain_ret>: > ffffffff81c01f7f: f6 .byte 0xf6 > > ffffffff81c01f80 <__x86_return_thunk>: > ffffffff81c01f80: c3 ret > ffffffff81c01f81: cc int3 > ffffffff81c01f82: 0f ae e8 lfence > ffffffff81c01f85: eb f9 jmp ffffffff81c01f80 <__x86_return_thunk> > ffffffff81c01f87: cc int3 > > So 5.15 doesn't need it. Great, thanks for looking into this, much appreciated. greg k-h
