Re: fix u32 printf specifier

[Martin KaFai Lau <kafai@fb.com>]

On Thu, Jun 03, 2021 at 12:41:57AM +0200, Benedict Schlueter wrote:
> On 02/06/2021 19:41, Martin KaFai Lau wrote:
> 
> > On Wed, Jun 02, 2021 at 05:23:19PM +0200, Benedict Schlueter wrote:
> > > Hi,
> > > 
> > > I assume its clear what this patch does.
> > > 
> > > 
> > >  From 9618e4475b812651c3fe481af885757675fc4ae2 Mon Sep 17 00:00:00 2001
> > > From: Benedict Schlueter <benedict.schlueter@rub.de>
> > > Date: Wed, 2 Jun 2021 17:16:13 +0200
> > > Subject: use correct format string specifier for unsigned 32 Bit
> > >   bounds print statements
> > > 
> > > Signed-off-by: Benedict Schlueter <benedict.schlueter@rub.de>
> > > ---
> > >   kernel/bpf/verifier.c | 4 ++--
> > >   1 file changed, 2 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> > > index 1de4b8c6ee42..e107996c7220 100644
> > > --- a/kernel/bpf/verifier.c
> > > +++ b/kernel/bpf/verifier.c
> > > @@ -690,11 +690,11 @@ static void print_verifier_state(struct
> > > bpf_verifier_env *env,
> > >                           (int)(reg->s32_max_value));
> > >                   if (reg->u32_min_value != reg->umin_value &&
> > >                       reg->u32_min_value != U32_MIN)
> > > -                    verbose(env, ",u32_min_value=%d",
> > > +                    verbose(env, ",u32_min_value=%u",
> > >                           (int)(reg->u32_min_value));
> > "%u" and (int) cast don't make sense.
> Yep, changed to unsigned int for consistency with the other cases. Is this
> necessary? Since reg->u32_min_value is already a unsigned 32 bit number.
cast is unnecessary.

> > It needs a proper commit message to explain why the change is needed
> > and also a Fixes tag.  Please refer to Documentation/bpf/bpf_devel_QA.rst.
> 
> Sorry should have read this more carefully before. Everything should be
> included right now.
> 
> From fd076dc5f2bd5ec4e9cb49530e77cf2d3e4f42c2 Mon Sep 17 00:00:00 2001
> From: Benedict Schlueter <benedict.schlueter@rub.de>
> Date: Wed, 2 Jun 2021 21:42:39 +0200
> Subject: [PATCH bpf-next]
>  use correct format string specifier for unsigned 32 bounds
> 
> when printing an unsigned value, it should be a positive number
> 
> verifier log before the patch
> ([...],s32_max_value=-2,u32_min_value=-16,u32_max_value=-2)
> 
> verifier log after the patch
> ([...],s32_max_value=-2,u32_min_value=4294967280,u32_max_value=4294967294)
> 
> 
> fixes 3f50f132d840 (bpf: Verifier, do explicit ALU32 bounds tracking)
Fixes: 3f50f132d840 ("bpf: Verifier, do explicit ALU32 bounds tracking")

which can be obtained by:
git log -1 --format='Fixes: %h ("%s")' 3f50f132d840