[PATCH] tty: serial: ucc_uart: use WARN_ON() instead of BUG()

[Akhilesh Patil]

On Mon, Jul 28, 2025 at 06:07:22AM +0200, Greg KH wrote:
> On Mon, Jul 28, 2025 at 07:14:25AM +0530, Akhilesh Patil wrote:
> > Replace BUG() with WARN_ON() as recommended in
> > Documentation/process/deprecated.rst
> > Fix system entering into unstable/break/undebuggable state due to use
> > of BUG(). Follow strict suggestions as per [1] [2].
> > 
> > Link: https://lore.kernel.org/lkml/CA+55aFy6jNLsywVYdGp83AMrXBo_P-pkjkphPGrO=82SPKCpLQ@mail.gmail.com/ [1]
> > Link: https://lore.kernel.org/lkml/CAHk-=whDHsbK3HTOpTF=ue_o04onRwTEaK_ZoJp_fjbqq4+=Jw@mail.gmail.com/ [2]
> > Signed-off-by: Akhilesh Patil <akhilesh at ee.iitb.ac.in>
> > ---
> >  drivers/tty/serial/ucc_uart.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/tty/serial/ucc_uart.c b/drivers/tty/serial/ucc_uart.c
> > index 0613f8c11ab1..6214ab1b67cb 100644
> > --- a/drivers/tty/serial/ucc_uart.c
> > +++ b/drivers/tty/serial/ucc_uart.c
> > @@ -223,7 +223,7 @@ static inline dma_addr_t cpu2qe_addr(void *addr, struct uart_qe_port *qe_port)
> >  
> >  	/* something nasty happened */
> >  	printk(KERN_ERR "%s: addr=%p\n", __func__, addr);
> > -	BUG();
> > +	WARN_ON(1);
> >  	return 0;
> >  }
> >  
> > @@ -242,7 +242,7 @@ static inline void *qe2cpu_addr(dma_addr_t addr, struct uart_qe_port *qe_port)
> >  
> >  	/* something nasty happened */
> >  	printk(KERN_ERR "%s: addr=%llx\n", __func__, (u64)addr);
> > -	BUG();
> > +	WARN_ON(1);
> >  	return NULL;
> >  }
> 
> You can't just do a search/replace for these types of things, otherwise
> we would have done so a long time ago.
> 

Hi greg, Agree. Let me dive deep to understand this BUG() -> WARN()
recommendation and come back after detailed analysis for this change.
> How did you test this patch?  The BUG() here assumes that if this ever

I have done only build check with NXP p1025rdb configuration as I do not
have this particular hardware handy.
> fires, the system is really broken, how have you recovered from that
> broken state?
> 
> thanks,
> 
> greg k-h

Thanks for the review :) 

Regards,
Akhilesh