linux-kernel - [PATCH] kexec: drop dependency on ARCH_SUPPORTS_KEXEC from CRASH

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Message-Id: <20231129220409.55006-1-ignat@cloudflare.com>
Date:   Wed, 29 Nov 2023 22:04:09 +0000
From:   Ignat Korchagin <ignat@...udflare.com>
To:     linux-kernel@...r.kernel.org
Cc:     Ignat Korchagin <ignat@...udflare.com>, kexec@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, akpm@...ux-foundation.org,
        eric_devolder@...oo.com, agordeev@...ux.ibm.com, bhe@...hat.com,
        kernel-team@...udflare.com, stable@...r.kernel.org
Subject: [PATCH] kexec: drop dependency on ARCH_SUPPORTS_KEXEC from CRASH_DUMP

In commit f8ff23429c62 ("kernel/Kconfig.kexec: drop select of KEXEC for
CRASH_DUMP") we tried to fix a config regression, where CONFIG_CRASH_DUMP
required CONFIG_KEXEC.

However, it was not enough at least for arm64 platforms. While further testing
the patch with our arm64 config I noticed that CONFIG_CRASH_DUMP is unavailable
in menuconfig. This is because CONFIG_CRASH_DUMP still depends on the new
CONFIG_ARCH_SUPPORTS_KEXEC introduced in commit 91506f7e5d21 ("arm64/kexec:
refactor for kernel/Kconfig.kexec") and on arm64 CONFIG_ARCH_SUPPORTS_KEXEC
requires CONFIG_PM_SLEEP_SMP=y, which in turn requires either CONFIG_SUSPEND=y
or CONFIG_HIBERNATION=y neither of which are set in our config.

Given that we already established that CONFIG_KEXEC (which is a switch for kexec
system call itself) is not required for CONFIG_CRASH_DUMP drop
CONFIG_ARCH_SUPPORTS_KEXEC dependency as well. The arm64 kernel builds just fine
with CONFIG_CRASH_DUMP=y and with both CONFIG_KEXEC=n and CONFIG_KEXEC_FILE=n
after f8ff23429c62 ("kernel/Kconfig.kexec: drop select of KEXEC for CRASH_DUMP")
and this patch are applied given that the necessary shared bits are included via
CONFIG_KEXEC_CORE dependency.

Fixes: 91506f7e5d21 ("arm64/kexec: refactor for kernel/Kconfig.kexec")
Cc: stable@...r.kernel.org # 6.6+: f8ff234: kernel/Kconfig.kexec: drop select of KEXEC for CRASH_DUMP
Cc: stable@...r.kernel.org # 6.6+
Signed-off-by: Ignat Korchagin <ignat@...udflare.com>
---
 kernel/Kconfig.kexec | 1 -
 1 file changed, 1 deletion(-)

diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec
index fc38f1ae3a30..946dffa048b7 100644
--- a/kernel/Kconfig.kexec
+++ b/kernel/Kconfig.kexec
@@ -96,7 +96,6 @@ config KEXEC_JUMP
 config CRASH_DUMP
 	bool "kernel crash dumps"
 	depends on ARCH_SUPPORTS_CRASH_DUMP
-	depends on ARCH_SUPPORTS_KEXEC
 	select CRASH_CORE
 	select KEXEC_CORE
 	help
-- 
2.39.2