[PATCH 4.14 19/62] arm64: percpu: Initialize ret in the default case

Greg Kroah-Hartman
2018-11-26T10:59:22Z

[ Upstream commit b5bb425871186303e6936fa2581521bdd1964a58 ]

Clang warns that if the default case is taken, ret will be
uninitialized.

./arch/arm64/include/asm/percpu.h:196:2: warning: variable 'ret' is used
uninitialized whenever switch default is taken
[-Wsometimes-uninitialized]
default:
^~~~~~~
./arch/arm64/include/asm/percpu.h:200:9: note: uninitialized use occurs
here
return ret;
^~~
./arch/arm64/include/asm/percpu.h:157:19: note: initialize the variable
'ret' to silence this warning
unsigned long ret, loop;
^
= 0

This warning appears several times while building the erofs filesystem.
While it's not strictly wrong, the BUILD_BUG will prevent this from
becoming a true problem. Initialize ret to 0 in the default case right
before the BUILD_BUG to silence all of these warnings.

Reported-by: Prasad Sodagudi <psodagud@codeaurora.org>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm64/include/asm/percpu.h | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/arm64/include/asm/percpu.h b/arch/arm64/include/asm/percpu.h
index 43393208229e..d79eaa816f29 100644
--- a/arch/arm64/include/asm/percpu.h
+++ b/arch/arm64/include/asm/percpu.h
@@ -93,6 +93,7 @@ static inline unsigned long __percpu_##op(void *ptr, \
: [val] "Ir" (val)); \
break; \
default: \
+ ret = 0; \
BUILD_BUG(); \
} \
\
@@ -122,6 +123,7 @@ static inline unsigned long __percpu_read(void *ptr, int size)
ret = READ_ONCE(*(u64 *)ptr);
break;
default:
+ ret = 0;
BUILD_BUG();
}

@@ -191,6 +193,7 @@ static inline unsigned long __percpu_xchg(void *ptr, unsigned long val,
: [val] "r" (val));
break;
default:
+ ret = 0;
BUILD_BUG();
}

--
2.17.1