Re: [PATCH v3] bitops: Fix shift overflow in GENMASK macros

From: Peter Zijlstra
Date: Tue Nov 04 2014 - 08:27:45 EST


On Tue, Nov 04, 2014 at 11:58:17AM +0100, Maxime COQUELIN wrote:
> On some 32 bits architectures, including x86, GENMASK(31, 0) returns 0
> instead of the expected ~0UL.
>
> This is the same on some 64 bits architectures with GENMASK_ULL(63, 0).
>
> This is due to an overflow in the shift operand, 1 << 32 for GENMASK,
> 1 << 64 for GENMASK_ULL.
>
> Fixes: 10ef6b0dffe404bcc54e94cb2ca1a5b18445a66b
> Cc: <stable@xxxxxxxxxxxxxxx> #v3.13+
> Reported-by: Eric Paire <eric.paire@xxxxxx>
> Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@xxxxxx>


There doesn't appear to be a clear maintainer for this file, so I'll try
and stick in in tip.

Thanks!

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