linux-kernel - [PATCH v2 17/24] x86/cpu: Make sure play

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Message-Id: <11e6ac1cf10f92967882926e3ac16287b50642f2.1676358308.git.jpoimboe@kernel.org>
Date:   Mon, 13 Feb 2023 23:05:51 -0800
From:   Josh Poimboeuf <jpoimboe@...nel.org>
To:     linux-kernel@...r.kernel.org
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Subject: [PATCH v2 17/24] x86/cpu: Make sure play_dead() doesn't return

After commit 076cbf5d2163 ("x86/xen: don't let xen_pv_play_dead()
return"), play_dead() never returns.  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@...nel.org>
---
 arch/x86/include/asm/smp.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index b4dbb20dab1a..8f628e08b25a 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -96,6 +96,7 @@ static inline void __cpu_die(unsigned int cpu)
 static inline void play_dead(void)
 {
 	smp_ops.play_dead();
+	BUG();
 }
 
 static inline void smp_send_reschedule(int cpu)
-- 
2.39.1