Re: [PATCH] objtool: prefer memory clobber & %= to volatile & __COUNTER__

From: Borislav Petkov
Date: Tue Jan 25 2022 - 13:50:29 EST


On Mon, Jan 24, 2022 at 03:38:38PM -0800, Nick Desaulniers wrote:
> $ wget https://download.01.org/0day-ci/archive/20220119/202201190702.XNSXrMTK-lkp@xxxxxxxxx/config
> -O .config
> $ make -j72 -s olddefconfig drivers/net/wireless/mac80211_hwsim.o
> drivers/net/wireless/mac80211_hwsim.o: warning: objtool:
> mac80211_hwsim_tx()+0x9aa: unreachable instruction
> $ gcc --version
> gcc (Debian 11.2.0-12) 11.2.0

Yap, I got mine with:

gcc (Debian 10.2.1-6) 10.2.1 20210110

but since you hit it with gcc11, I don't see why I won't hit it with
gcc10.

> :(

You said it.

> Let me see if I can come up with a reduced test case that I will
> report upstream to https://gcc.gnu.org/bugzilla/.

Sounds good.

Please send the bug # once you have that so that I can add myself to Cc.

Thx.

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette