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perf/x86: Fix broken LBR fixup code

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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 <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Arun Sharma <asharma@fb.com>
Link: http://lkml.kernel.org/r/20120611134426.GA7542@quad
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Stephane Eranian 2012-06-11 15:44:26 +02:00 committed by Ingo Molnar
parent 9ee6ddc9da
commit 25f4298582
1 changed files with 1 additions and 1 deletions
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2
arch/x86/lib/usercopy.c
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@ -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 {