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From:   Arnd Bergmann <arnd@arndb.de>
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Subject: [PATCH] mm/kasan: fix kasan_check_read() compiler warning
Date:   Tue,  9 Jul 2019 20:35:40 +0200
Message-Id: <20190709183612.2693974-1-arnd@arndb.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The kasan_check_read() is marked 'inline', which usually includes
the 'always_inline' attribute. In some configuration, gcc decides that
it cannot inline this, causing a build failure:

In file included from include/linux/compiler.h:257,
                 from arch/x86/include/asm/current.h:5,
                 from include/linux/sched.h:12,
                 from include/linux/ratelimit.h:6,
                 from fs/dcache.c:18:
include/linux/compiler.h: In function 'read_word_at_a_time':
include/linux/kasan-checks.h:31:20: error: inlining failed in call to always_inline 'kasan_check_read': function attribute mismatch
 static inline bool kasan_check_read(const volatile void *p, unsigned int size)
                    ^~~~~~~~~~~~~~~~
In file included from arch/x86/include/asm/current.h:5,
                 from include/linux/sched.h:12,
                 from include/linux/ratelimit.h:6,
                 from fs/dcache.c:18:
include/linux/compiler.h:280:2: note: called from here
  kasan_check_read(addr, 1);
  ^~~~~~~~~~~~~~~~~~~~~~~~~

While I have no idea why it does this, but changing the call to the
internal __kasan_check_read() fixes the issue.

Fixes: dc55b51f312c ("mm/kasan: introduce __kasan_check_{read,write}")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 include/linux/compiler.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index f0fd5636fddb..22909500ba1d 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -277,7 +277,7 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
 static __no_kasan_or_inline
 unsigned long read_word_at_a_time(const void *addr)
 {
-	kasan_check_read(addr, 1);
+	__kasan_check_read(addr, 1);
 	return *(unsigned long *)addr;
 }
 
-- 
2.20.0