| Message ID | d0c3ff5349adfe8fd227acc236ae2c278a05eb4c.1676358308.git.jpoimboe@kernel.org (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | cpu,sched: Mark arch_cpu_idle_dead() __noreturn | expand |
On 14/2/23 08:05, Josh Poimboeuf wrote: > play_dead() doesn't return. Make that more explicit with a BUG(). > > BUG() is preferable to unreachable() because BUG() is a more explicit > failure mode and avoids undefined behavior like falling off the edge of > the function into whatever code happens to be next. > > Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> > --- > arch/sh/include/asm/smp-ops.h | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/sh/include/asm/smp-ops.h b/arch/sh/include/asm/smp-ops.h > index e27702130eb6..63866b1595a0 100644 > --- a/arch/sh/include/asm/smp-ops.h > +++ b/arch/sh/include/asm/smp-ops.h > @@ -27,6 +27,7 @@ static inline void plat_smp_setup(void) > static inline void play_dead(void) > { > mp_ops->play_dead(); > + BUG(); > } Shouldn't we decorate plat_smp_ops::play_dead() as noreturn first?
On Tue, Feb 14, 2023 at 08:57:39AM +0100, Philippe Mathieu-Daudé wrote: > On 14/2/23 08:05, Josh Poimboeuf wrote: > > play_dead() doesn't return. Make that more explicit with a BUG(). > > > > BUG() is preferable to unreachable() because BUG() is a more explicit > > failure mode and avoids undefined behavior like falling off the edge of > > the function into whatever code happens to be next. > > > > Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> > > --- > > arch/sh/include/asm/smp-ops.h | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/sh/include/asm/smp-ops.h b/arch/sh/include/asm/smp-ops.h > > index e27702130eb6..63866b1595a0 100644 > > --- a/arch/sh/include/asm/smp-ops.h > > +++ b/arch/sh/include/asm/smp-ops.h > > @@ -27,6 +27,7 @@ static inline void plat_smp_setup(void) > > static inline void play_dead(void) > > { > > mp_ops->play_dead(); > > + BUG(); > > } > > Shouldn't we decorate plat_smp_ops::play_dead() as noreturn first? I guess it really depends on how far we want to go down the __noreturn rabbit hole. To keep the patch set constrained yet still useful I stopped when I got to a function pointer, as I think it still needs a BUG() afterwards either way. That said, there would still be benefits of adding __noreturn to function pointers, I just wanted to keep the patch set down to a manageable size ;-)
diff --git a/arch/sh/include/asm/smp-ops.h b/arch/sh/include/asm/smp-ops.h index e27702130eb6..63866b1595a0 100644 --- a/arch/sh/include/asm/smp-ops.h +++ b/arch/sh/include/asm/smp-ops.h @@ -27,6 +27,7 @@ static inline void plat_smp_setup(void) static inline void play_dead(void) { mp_ops->play_dead(); + BUG(); } extern void register_smp_ops(struct plat_smp_ops *ops);
play_dead() doesn't return. Make that more explicit with a BUG(). BUG() is preferable to unreachable() because BUG() is a more explicit failure mode and avoids undefined behavior like falling off the edge of the function into whatever code happens to be next. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> --- arch/sh/include/asm/smp-ops.h | 1 + 1 file changed, 1 insertion(+)