Re: [Qemu-devel] [PATCH] spapr_pci: Fix unsafe signed/unsigned comparisons

[Alexander Graf <agraf@suse.de>]

On 19.03.15 05:14, David Gibson wrote:
> spapr_pci.c contains a number of expressions of the form (uval == -1) or
> (uval != -1), where 'uval' is an unsigned value.
> 
> This mostly works in practice, because as long as the width of uval is
> greater or equal than that of (int), the -1 will be promoted to the
> unsigned type, which is the expected outcome.
> 
> However, at least for the cases where uval is uint32_t, this would break
> on platforms where sizeof(int) > 4 (and a few such do exist), because then
> the uint32_t value would be promoted to the larger int type, and never be
> equal to -1.
> 
> This patch fixes these errors.  The fixes for the (uint32_t) cases are
> necessary as described above.  I've made similar fixes to (uint64_t) and
> (hwaddr) cases.  Those are strictly theoretical, since I don't know of any
> platforms where sizeof(int) > 8, but hey, it's not that hard so we might
> as well be strictly C standard compliant.
> 
> Reported-by: Markus Armbruster <armbru@redhat.com>
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

Thanks, applied to ppc-next-2.4.


Alex