[PATCH 4.4 101/115] powerpc/perf/hv-24x7: Fix incorrect comparison in memord

From: Greg Kroah-Hartman
Date: Mon Dec 18 2017 - 12:54:34 EST

4.4-stable review patch. If anyone has any objections, please let me know.


From: Michael Ellerman <mpe@xxxxxxxxxxxxxx>

[ Upstream commit 05c14c03138532a3cb2aa29c2960445c8753343b ]

In the hv-24x7 code there is a function memord() which tries to
implement a sort function return -1, 0, 1. However one of the
conditions is incorrect, such that it can never be true, because we
will have already returned.

I don't believe there is a bug in practice though, because the
comparisons are an optimisation prior to calling memcmp().

Fix it by swapping the second comparision, so it can be true.

Reported-by: David Binderman <dcb314@xxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
arch/powerpc/perf/hv-24x7.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -514,7 +514,7 @@ static int memord(const void *d1, size_t
if (s1 < s2)
return 1;
- if (s2 > s1)
+ if (s1 > s2)
return -1;

return memcmp(d1, d2, s1);