* [PATCH] powerpc/perf/hv-24x7: Fix incorrect comparison in memord
@ 2017-10-09 10:52 Michael Ellerman
2017-10-24 8:08 ` Michael Ellerman
0 siblings, 1 reply; 2+ messages in thread
From: Michael Ellerman @ 2017-10-09 10:52 UTC (permalink / raw)
To: linuxppc-dev; +Cc: bauerman
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@hotmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/perf/hv-24x7.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c
index 9c88b82f6229..72238eedc360 100644
--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -540,7 +540,7 @@ static int memord(const void *d1, size_t s1, const void *d2, size_t s2)
{
if (s1 < s2)
return 1;
- if (s2 > s1)
+ if (s1 > s2)
return -1;
return memcmp(d1, d2, s1);
--
2.7.4
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: powerpc/perf/hv-24x7: Fix incorrect comparison in memord
2017-10-09 10:52 [PATCH] powerpc/perf/hv-24x7: Fix incorrect comparison in memord Michael Ellerman
@ 2017-10-24 8:08 ` Michael Ellerman
0 siblings, 0 replies; 2+ messages in thread
From: Michael Ellerman @ 2017-10-24 8:08 UTC (permalink / raw)
To: Michael Ellerman, linuxppc-dev; +Cc: bauerman
On Mon, 2017-10-09 at 10:52:44 UTC, Michael Ellerman wrote:
> 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@hotmail.com>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Applied to powerpc next.
https://git.kernel.org/powerpc/c/05c14c03138532a3cb2aa29c296044
cheers
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