From: Linus Torvalds Date: Sun, 16 Nov 2014 19:00:42 +0000 (-0800) Subject: x86-64: make csum_partial_copy_from_user() error handling consistent X-Git-Tag: submit/tizen/20160607.132125~3542 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3b91270a0a2fe00b7aa1ce16b3ecf055315c64e3;p=sdk%2Femulator%2Femulator-kernel.git x86-64: make csum_partial_copy_from_user() error handling consistent Al Viro pointed out that the x86-64 csum_partial_copy_from_user() is somewhat confused about what it should do on errors, notably it mostly clears the uncopied end result buffer, but misses that for the initial alignment case. All users should check for errors, so it's dubious whether the clearing is even necessary, and Al also points out that we should probably clean up the calling conventions, but regardless of any future changes to this function, the fact that it is inconsistent is just annoying. So make the __get_user() failure path use the same error exit as all the other errors do. Reported-by: Al Viro Cc: David Miller Cc: Andi Kleen Signed-off-by: Linus Torvalds --- diff --git a/arch/x86/lib/csum-wrappers_64.c b/arch/x86/lib/csum-wrappers_64.c index 7609e0e..1318f75 100644 --- a/arch/x86/lib/csum-wrappers_64.c +++ b/arch/x86/lib/csum-wrappers_64.c @@ -41,9 +41,8 @@ csum_partial_copy_from_user(const void __user *src, void *dst, while (((unsigned long)src & 6) && len >= 2) { __u16 val16; - *errp = __get_user(val16, (const __u16 __user *)src); - if (*errp) - return isum; + if (__get_user(val16, (const __u16 __user *)src)) + goto out_err; *(__u16 *)dst = val16; isum = (__force __wsum)add32_with_carry(