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Sender: Guenter Roeck <groeck7@gmail.com>
From:   Guenter Roeck <linux@roeck-us.net>
To:     Heiko Carstens <hca@linux.ibm.com>
Cc:     Vasily Gorbik <gor@linux.ibm.com>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
        Guenter Roeck <linux@roeck-us.net>
Subject: [PATCH] s390: Add WARN_DYNAMIC_STACK dependencies
Date:   Tue, 14 Sep 2021 21:40:10 -0700
Message-Id: <20210915044010.640499-1-linux@roeck-us.net>
MIME-Version: 1.0
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s390:allmodconfig fails to build with the following errors.

arch/s390/kernel/syscall.c: In function '__do_syscall':
arch/s390/kernel/syscall.c:168:1: error:
	'__do_syscall' uses dynamic stack allocation

lib/test_kasan.c: In function 'kasan_alloca_oob_right':
lib/test_kasan.c:782:1: error:
	'kasan_alloca_oob_right' uses dynamic stack allocation

lib/test_kasan.c: In function 'kasan_alloca_oob_left':
lib/test_kasan.c:767:1: error:
	'kasan_alloca_oob_left' uses dynamic stack allocation

The first error is seen if RANDOMIZE_KSTACK_OFFSET_DEFAULT,
WARN_DYNAMIC_STACK, and WERROR are enabled. The other problems
are seen if KASAN_KUNIT_TEST, WARN_DYNAMIC_STACK, and WERROR
are enabled.

It does not make sense to abort a build in that situation.
If either RANDOMIZE_KSTACK_OFFSET_DEFAULT or KASAN_KUNIT_TEST
is enabled, dynamic stack allocation is on purpose and should
not fail the build. Add dependencies to reflect that situation.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 arch/s390/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 2bd90c51efd3..776b730e2d15 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -688,6 +688,7 @@ config STACK_GUARD
 config WARN_DYNAMIC_STACK
 	def_bool n
 	prompt "Emit compiler warnings for function with dynamic stack usage"
+	depends on !WERROR || (!RANDOMIZE_KSTACK_OFFSET_DEFAULT && !KASAN_KUNIT_TEST)
 	help
 	  This option enables the compiler option -mwarn-dynamicstack. If the
 	  compiler supports this options generates warnings for functions
-- 
2.33.0