Messages in this thread | | | Date | Wed, 23 Nov 2022 11:12:42 -0800 | From | "Paul E. McKenney" <> | Subject | Re: objtool warning for next-20221118 |
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On Wed, Nov 23, 2022 at 10:19:41AM -0800, Josh Poimboeuf wrote: > On Wed, Nov 23, 2022 at 09:49:51AM -0800, Paul E. McKenney wrote: > > > > > Perhaps the best way would be to stick a REACHABLE annotation in > > > > > arch_cpu_idle_dead() or something? > > > > > > > > When I apply this on -next, I still get the objtool complaint. > > > > Is there something else I should also be doing? > > > > > > Silly GCC is folding the inline asm. This works (but still doesn't seem > > > like the right approach): > > > > > > diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c > > > index 26e8f57c75ad..128e7d78fedf 100644 > > > --- a/arch/x86/kernel/process.c > > > +++ b/arch/x86/kernel/process.c > > > @@ -702,7 +702,7 @@ static void (*x86_idle)(void); > > > #ifndef CONFIG_SMP > > > static inline void play_dead(void) > > > { > > > - BUG(); > > > + _BUG_FLAGS(ASM_UD2, 0, ASM_REACHABLE); > > > } > > > #endif > > > > I tried this, and still get: > > > > vmlinux.o: warning: objtool: do_idle+0x156: unreachable instruction > > > > Maybe my gcc is haunted? > > Weird, it worked for me. I have > > gcc version 12.2.1 20220819 (Red Hat 12.2.1-2) (GCC)
Me, I have these, so quite a bit older:
gcc version 8.5.0 20210514 (Red Hat 8.5.0-15) (GCC) gcc version 9.4.0 (Ubuntu 9.4.0-1ubuntu1~20.04.1)
> and I can't really fathom why that wouldn't work. Maybe it's a > different issue? The "unreachable instruction" warning is limited to > one, so when a first warning gets fixed, a second warning might suddenly > become visible. > > Can you attach arch/x86/kernel/process.o?
Attached!
Thanx, Paul [unhandled content-type:application/x-object] | |