On Wed, 8 Jan 2025 at 04:00, Paul Moore <paul@xxxxxxxxxxxxxx> wrote: > > On Dec 16, 2024 =?UTF-8?q?Christian=20G=C3=B6ttsche?= <cgoettsche@xxxxxxxxxxxxx> wrote: > > > > Avoid using nontransitive comparison to prevent unexpected sorting > > results due to (well-defined) overflows. > > See https://www.qualys.com/2024/01/30/qsort.txt for a related issue in > > glibc's qsort(3). > > > > Signed-off-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx> > > --- > > security/selinux/ss/policydb.c | 18 ++++++++++-------- > > 1 file changed, 10 insertions(+), 8 deletions(-) > > > > diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c > > index 3ba5506a3fff..eb944582d7a6 100644 > > --- a/security/selinux/ss/policydb.c > > +++ b/security/selinux/ss/policydb.c > > @@ -37,6 +37,8 @@ > > #include "mls.h" > > #include "services.h" > > > > +#define spaceship_cmp(a, b) (((a) > (b)) - ((a) < (b))) > > I'll admit that it took me a while to figure out why you decided to > name this macro "spaceship_cmp", and then I had a little laugh when > I realized why it was called the "spaceship" operator :) > > Anyway, while the spaceship operator is likely familiar to people who > have a Perl background, the kernel is still mostly a C project so I > don't think we can expect a base understanding of Perl, especially > these days as Perl isn't as popular as in the past. Can we rename > this to something else that makes more sense in the context of C? There seem to be 4 similar macros already in the kernel, 3 named cmp_int() and one instance named cmp_ptr(). So I am going with cmp_int() in v3 for now, but I am open for other suggestions. > > -- > paul-moore.com
