Re: [PATCH] replace BUG_ON to WARN_ON

Hyunmin Lee
2023-02-01T10:03:31Z

On Tue, Jan 31, 2023 at 03:47:05PM +0200, Mike Rapoport wrote:
> On Tue, Jan 31, 2023 at 07:56:29PM +0900, Hyunmin Lee wrote:
> > On Mon, Jan 30, 2023 at 12:14:04PM +0200, Mike Rapoport wrote:
> > > Hi,
> > >
> > > On Fri, Jan 27, 2023 at 08:58:44PM +0900, Hyunmin Lee wrote:
> > > > Replace unnacessary BUG_ON to WARN_ON. These BUG_ONs verify aruguments of a function. Thus, the WARN_ONs return an EINVAL error when their condition is true.
> > >
> > > Some users enable panic_on_warn, so for them WARN_ON will still crash a
> > > machine.
> > >
> > > I think a simple if() will be sufficient.
> > >
> > Hi Mike,
> >
> > Thank you for your advice.
> > Would you please give feedback about the below opinion?
> > - Printing warning messages is helpful to inform what happened in the system to the users.
> > - When a simple if() is used instead of WARN_ON, the if() should print a warning message.
> > - The condition of the simple if() should also have unlikely() for optimization of system performance.
> > - WARN_ON is a macro doing like thoes easily. It has a notifying function and unlikely optimization.
> > - Eventhough WARN_ON will still crash like BUG_ON by some users who enable panic_on_warn, it is their intention. They should accept the crash by WARN_ON.
> > - Therefore, using WARN_ON looks like natural and efficient.
>
> As this is a validation of the function parameters, there is no need in
> warning messages and if(unlikely()) will do. There is really no point in
> WARN_ON() for something that's totally recoverable and very unlikely to
> happen.
>
> > Best,
> > Hyunmin
>
> --
> Sincerely yours,
> Mike.
Hi Mike,

According to your guidance, I will send a v3 patch.
Thanks a lot.

Best,
Min