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Date:   Mon, 21 Mar 2022 16:28:05 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Stephen Rothwell <sfr@canb.auug.org.au>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux Next Mailing List <linux-next@vger.kernel.org>,
        mhiramat@kernel.org, rostedt@goodmis.org, ast@kernel.org,
        hjl.tools@gmail.com, rick.p.edgecombe@intel.com, rppt@kernel.org,
        linux-toolchains@vger.kernel.org, Andrew.Cooper3@citrix.com,
        ndesaulniers@google.com
Subject: Re: linux-next: build warnings after merge of the tip tree
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On Mon, Mar 21, 2022 at 02:45:16PM +0100, Peter Zijlstra wrote:
> On Mon, Mar 21, 2022 at 02:08:23PM +0100, Peter Zijlstra wrote:
> > On Mon, Mar 21, 2022 at 02:04:05PM +0100, Peter Zijlstra wrote:
> > > On Mon, Mar 21, 2022 at 01:55:49PM +0100, Peter Zijlstra wrote:
> > > > On Mon, Mar 21, 2022 at 02:03:27PM +1100, Stephen Rothwell wrote:
> > > > > Hi all,
> > > > > 
> > > > > After merging the tip tree, today's linux-next build (x864 allmodconfig)
> > > > > produced these new warnings:
> > > > > 
> > > > > vmlinux.o: warning: objtool: arch_rethook_prepare()+0x55: relocation to !ENDBR: arch_rethook_trampoline+0x0
> > > > > vmlinux.o: warning: objtool: arch_rethook_trampoline_callback()+0x3e: relocation to !ENDBR: arch_rethook_trampoline+0x0
> > > > > vmlinux.o: warning: objtool: unwind_next_frame()+0x93e: relocation to !ENDBR: arch_rethook_trampoline+0x0
> > > > > vmlinux.o: warning: objtool: unwind_next_frame()+0x5f2: relocation to !ENDBR: arch_rethook_trampoline+0x0
> > > > > vmlinux.o: warning: objtool: unwind_next_frame()+0x4a7: relocation to !ENDBR: arch_rethook_trampoline+0x0
> > > > > vmlinux.o: warning: objtool: __rethook_find_ret_addr()+0x81: relocation to !ENDBR: arch_rethook_trampoline+0x0
> > > > > vmlinux.o: warning: objtool: __rethook_find_ret_addr()+0x90: relocation to !ENDBR: arch_rethook_trampoline+0x0
> > > > > vmlinux.o: warning: objtool: rethook_trampoline_handler()+0x8c: relocation to !ENDBR: arch_rethook_trampoline+0x0
> > > > > vmlinux.o: warning: objtool: rethook_trampoline_handler()+0x9b: relocation to !ENDBR: arch_rethook_trampoline+0x0
> > > > 
> > > > Hurmph, lemme go figure out where that code comes from, I've not seen
> > > > those.
> > > 
> > > Ahh, something tracing. I'll go do some patches on top of it.
> > 
> > Also, that x86 patch has never his x86@kernel.org and doesn't have an
> > ACK from any x86 person :-(((
> 
> Worse, it adds a 3rd return trampoline without replacing any of the
> existing two :-(
> 
> Why was this merged?

It additionally gets ret wrong:

  vmlinux.o: warning: objtool: arch_rethook_trampoline()+0x4a: missing int3 after ret

and afaict regs->ss is garbage (much like kretprobes it appears).

Can we please unmerge this stuff and try again later?