FAILED: patch "[PATCH] panic: flatten nmi_panic control flow" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] panic: flatten nmi_panic control flow" failed to apply to 5.15-stable tree

[Sasha Levin]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 75eb687ff2bcec9fba31bbe266e5f91e5c283efe
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107060543-failed-5.15-75eb687ff2bc@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From 75eb687ff2bcec9fba31bbe266e5f91e5c283efe Mon Sep 17 00:00:00 2001
From: Bradley Morgan <brads@mainlining.org>
Date: Wed, 16 Sep 2026 18:29:53 +0000
Subject: [PATCH] panic: flatten nmi_panic control flow

panic() is __noreturn, so the else after panic_try_start() is dead.  Drop
it so the force_cpu path can be added cleanly on top.

Link: https://lore.kernel.org/20260916182957.7788-3-brads@mainlining.org
Signed-off-by: Bradley Morgan <brads@mainlining.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Guenetr Roeck <linux@roeck-us.net>
Cc: Sashiko <sashiko-bot@kernel.org>
Cc: Wang Jinchao <wangjinchao600@gmail.com>
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: <stable@vger.kernel.org>
---
 kernel/panic.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/panic.c b/kernel/panic.c
index 08072bfae4221..5646d4fb82b7d 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -517,7 +517,8 @@ void nmi_panic(struct pt_regs *regs, const char *msg)
 {
 	if (panic_try_start())
 		panic("%s", msg);
-	else if (panic_on_other_cpu())
+
+	if (panic_on_other_cpu())
 		nmi_panic_self_stop(regs);
 }
 EXPORT_SYMBOL(nmi_panic);
-- 
2.53.0

[PATCH 5.15.y] panic: flatten nmi_panic control flow

[Sasha Levin]

From: Bradley Morgan <brads@mainlining.org>

[ Upstream commit 75eb687ff2bcec9fba31bbe266e5f91e5c283efe ]

panic() is __noreturn, so the else after panic_try_start() is dead.  Drop
it so the force_cpu path can be added cleanly on top.

Link: https://lore.kernel.org/20260916182957.7788-3-brads@mainlining.org
Signed-off-by: Bradley Morgan <brads@mainlining.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Guenetr Roeck <linux@roeck-us.net>
Cc: Sashiko <sashiko-bot@kernel.org>
Cc: Wang Jinchao <wangjinchao600@gmail.com>
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: <stable@vger.kernel.org>
[ sashal: used existing old_cpu comparisons instead of panic_try_start() and panic_on_other_cpu() ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/panic.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/panic.c b/kernel/panic.c
index 3b14c6d123ddc..2db714911168b 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -195,7 +195,8 @@ void nmi_panic(struct pt_regs *regs, const char *msg)
 
 	if (old_cpu == PANIC_CPU_INVALID)
 		panic("%s", msg);
-	else if (old_cpu != cpu)
+
+	if (old_cpu != cpu)
 		nmi_panic_self_stop(regs);
 }
 EXPORT_SYMBOL(nmi_panic);
-- 
2.53.0