From 25f42985825dd93f0593efe454e54c2aa13f7830 Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Mon, 11 Jun 2012 15:44:26 +0200 Subject: [PATCH] perf/x86: Fix broken LBR fixup code I noticed that the LBR fixups were not working anymore on programs where they used to. I tracked this down to a recent change to copy_from_user_nmi(): db0dc75d640 ("perf/x86: Check user address explicitly in copy_from_user_nmi()") This commit added a call to __range_not_ok() to the copy_from_user_nmi() routine. The problem is that the logic of the test must be reversed. __range_not_ok() returns 0 if the range is VALID. We want to return early from copy_from_user_nmi() if the range is NOT valid. Signed-off-by: Stephane Eranian Signed-off-by: Peter Zijlstra Acked-by: Arun Sharma Link: http://lkml.kernel.org/r/20120611134426.GA7542@quad Signed-off-by: Ingo Molnar --- arch/x86/lib/usercopy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c index 677b1ed..4f74d94 100644 --- a/arch/x86/lib/usercopy.c +++ b/arch/x86/lib/usercopy.c @@ -22,7 +22,7 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n) void *map; int ret; - if (__range_not_ok(from, n, TASK_SIZE) == 0) + if (__range_not_ok(from, n, TASK_SIZE)) return len; do { -- 2.7.4