Date:   Fri, 10 Mar 2023 20:54:49 -0000
From:   "tip-bot2 for Josh Poimboeuf" <tip-bot2@linutronix.de>
Sender: tip-bot2@linutronix.de
Reply-to: linux-kernel@vger.kernel.org
To:     linux-tip-commits@vger.kernel.org
Subject: [tip: objtool/core] x86/cpu: Make sure play_dead() doesn't return
Cc:     Josh Poimboeuf <jpoimboe@kernel.org>, x86@kernel.org,
        linux-kernel@vger.kernel.org
In-Reply-To: <11e6ac1cf10f92967882926e3ac16287b50642f2.1676358308.git.jpoimboe@kernel.org>
References: <11e6ac1cf10f92967882926e3ac16287b50642f2.1676358308.git.jpoimboe@kernel.org>
MIME-Version: 1.0
Message-ID: <167848168944.5837.18023341418882320171.tip-bot2@tip-bot2>
Robot-ID: <tip-bot2@linutronix.de>
Robot-Unsubscribe: Contact <mailto:tglx@linutronix.de> to get blacklisted from these emails
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Precedence: bulk

The following commit has been merged into the objtool/core branch of tip:

Commit-ID:     a02f50b573b3c90a3633a5ab67435fe4c0de144d
Gitweb:        https://git.kernel.org/tip/a02f50b573b3c90a3633a5ab67435fe4c0de144d
Author:        Josh Poimboeuf <jpoimboe@kernel.org>
AuthorDate:    Mon, 13 Feb 2023 23:05:51 -08:00
Committer:     Josh Poimboeuf <jpoimboe@kernel.org>
CommitterDate: Wed, 08 Mar 2023 08:44:26 -08:00

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.

Link: https://lore.kernel.org/r/11e6ac1cf10f92967882926e3ac16287b50642f2.1676358308.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.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 b4dbb20..8f628e0 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)