From: Lennert Buytenhek Date: Fri, 22 Feb 2008 23:23:48 +0000 (+0100) Subject: [ARM] 4837/1: make __get_unaligned_*() return unsigned types X-Git-Tag: v2.6.25-rc4~128^2~7 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=94a3f78566ef98a48814d82892f28bb741624cb8;p=linux-2.6-omap-h63xx.git [ARM] 4837/1: make __get_unaligned_*() return unsigned types Eric Sandeen tracked an XFS on ARM corruption bug down to a function under fs/xfs/ involving some get_unaligned() calls on u64 pointers. As it turns out, calling ARM's get_unaligned() on a u64 pointer pointing to the following byte sequence: 80 81 82 83 84 85 86 87 would return ffffffff83828180 (LE mode.) This turns out to be because of implicit u8 -> int promotion in ARM's implementation of various helpers for get_unaligned(), causing them to accidentally return signed instead of unsigned values, which in turn caused the subsequent casts to unsigned long long in __get_unaligned_8_[bl]e() to sign-extend the lower words. Fix by casting the return values of __get_unaligned_[24]_[bl]e() to unsigned int. Cc: Eric Sandeen Cc: Rabeeh Khoury Cc: Nicolas Pitre Signed-off-by: Lennert Buytenhek Signed-off-by: Russell King --- diff --git a/include/asm-arm/unaligned.h b/include/asm-arm/unaligned.h index 8431f6eed5c..5db03cf3b90 100644 --- a/include/asm-arm/unaligned.h +++ b/include/asm-arm/unaligned.h @@ -40,16 +40,16 @@ extern int __bug_unaligned_x(const void *ptr); */ #define __get_unaligned_2_le(__p) \ - (__p[0] | __p[1] << 8) + (unsigned int)(__p[0] | __p[1] << 8) #define __get_unaligned_2_be(__p) \ - (__p[0] << 8 | __p[1]) + (unsigned int)(__p[0] << 8 | __p[1]) #define __get_unaligned_4_le(__p) \ - (__p[0] | __p[1] << 8 | __p[2] << 16 | __p[3] << 24) + (unsigned int)(__p[0] | __p[1] << 8 | __p[2] << 16 | __p[3] << 24) #define __get_unaligned_4_be(__p) \ - (__p[0] << 24 | __p[1] << 16 | __p[2] << 8 | __p[3]) + (unsigned int)(__p[0] << 24 | __p[1] << 16 | __p[2] << 8 | __p[3]) #define __get_unaligned_8_le(__p) \ ((unsigned long long)__get_unaligned_4_le((__p+4)) << 32 | \